Whats Your MaP (kPa)?

[ChimpOnGas]

A quick question as per the title and probably only for those with aftermarket ECUs who have access to this information easily, well two questions actually . I recently noticed a Griff 5.0 litre that belongs to a mate produces noticeably different Map figures to my 4.0 Chimaera, I should also say at this point he runs a Kent 885 cam.

My mate's Griff 500 is like this:

• Idles at just 35 kPa

• When pulling away and his engine initially loads up his kPa momentarily peaks at only 55 kPa

These figures in contrast to my 4.0HC that runs a Stealth cam and a lightened 18lbs flywheel:

• Idles quite a bit higher at 50 kPa

• When pulling away my engine initially loads up a lot higher peaking momentarily at 80 kPa

Admittedly I do idle around 50/100rpm higher than the Griff so I appreciate this will have an impact on the idle MaP figures, but feel I need that fraction extra engine speed for the engine to idle equally smoothly.

Question One: I appreciate a cam will play a big part here but is there really such a big difference between the V8 Development Stealth cam I have and the 885 in my mates Griffith?

Obviously the other big difference is my mate has a 5.0 litre and I have the baby 4.0, but even so I'm still quite surprised at the differences, overall my mates Griff MaP figures are significantly lower than mine except as you would expect under hard acceleration where the two engines produce the same figures, but his idle kPa's do also seem more stable than mine too .

Question Two: Are these differences more a result of the different camshaft profiles used or does the capacity difference play a bigger role in all this than I'd assumed?

Discuss

Edited by ChimpOnGas on Monday 17th September 12:02

[ChimpOnGas]

Steve_D said:

Not sure we should respond to this as the shortness of the post leads me to believe you are not who you say you are.

Steve

very funny Steve, should I make it longer?










Now how about your thoughts on my questions mate

I value you opinion, and I'd be especially keen to see the MaP figures from others running a V8 Developments Stealth cam

Perhaps the Kent 885 is just a more streetable profile than the Stealth cam I run?

I'm not complaining about my Stealth by the way, I actually love it, I'm just interested in better understanding if the lower MaP figures I saw on my mate's 500 are more down to cam differences, the extra engine capacity... or maybe something else I hadn't considered

[ChimpOnGas]

I'm not so sure, both cars in this case are using the exact same MaP sensor and both are on the same engine management system, so I'd say the comparison is fair.

I'm interested in naturally aspirated cars really, what I'm looking to establish is what vacuum different RV8 TVRs idle at on different cams.

There was definitely a big difference between my mates 5.0 litre Griffith running an 885 and my 4.0 Chimaera on a Stealth cam, and it's not just numbers on a screen, its noticeable to the ear and in the minimum idle speed each engine will tolerate to remain smooth.

Its a shame I can't now compare the detailed specifications of each camshaft as I expect this would be quite revealing, I suspect my Stealth has quite a bit more overlap than the 885.

Anyone else want to share their figures, idle and peak load MaP in kPa as you pull away would be great as this is where the Griff 500 fitted with an 885 differed most from my 4.0 Chimaera running a V8 Developments Stealth cam.

I too was amazed my mate's Griff managed 35 kPa at idle, it was however remarkably smooth so I feel confident we can trust the number.

[ChimpOnGas]

OleVix said:

4.6 10-1 comp stage3 stealth cam NA now, turbo sold

on ms3extra 45kpa idle 950 rev and from 95-100 at absolutely full chat, 100.2kpa at 3750.

Why no turbo Ole

[ChimpOnGas]

SuperApeInGoodShape said:

SILICONEKID 357HP said:

Throttle response is much slower ,well that's what I've been told .

MAP with TPS for Acceleration Enrichment is a good combo.

Alpha-N /TPS on its own is a bad predictor of load at anything but full throttle.

^^^This^^^

True engine load is what you need to know, and what you and your ECU really should be working with.

So what's this Alpha-N thingy anyway

Well, Alpha is just throttle angle and N is just RPM (engine speed)

So with Alpha-N injector duration (opening times) and ignition timing can only be a calculation based on those two parameters.... neither of which are a true refection of engine load. Even with the two it doesn't matter how clever the calculation is you could never say what you end up with is true engine load

Vacuum on the other hand is a far a more accurate representation of true engine load because an engine is just a big vacuum pump pulling against a restriction valve (the throttle butterfly), as you open the throttle the vacuum (or depression to use the correct term) falls in the inlet manifold/plenum chamber, conversely if engine speed is high and the engine is pulling hard against an almost closed throttle butterfly the depression will increase considerably.

So if you know your depression you actually don't need your throttle position because depression is a reflection of the throttle position and to some degree engine speed, it's important to remember at this point that the principle of using depression to measure engine load was used to great effect long before throttle position sensors, electronic fuel injection and distributorless ignition systems, it's also completely proven.

A manifild absolute pressure sensor is really nothing more than an electronic vacuum advance unit, rather than physically translating manifold depression into mechanical movement acting on the base plate of the distributor to advance the ignition timing, the MaP sensor translates manifold depression into tiny variations in voltage which of course is something a ECU can work with.

Clearly an engine management system using a MaP sensor to determine engine load will be measuring true engine speed and throttle position too, this is critical additional information. But to do away with the MaP sensor and just rely on engine speed and throttle position (Alpha-N) is missing a massive trick as far as I'm concerned, doing so on a race car may be fine but for a car used on the road that must be as smooth as possible under a myriad of driving conditions and so true engine loads you really would be mad not to use MaP.

It may be what you've heard Daz is that throttle response is better using Alpha-N but this really shouldn't be the case, a good system using MaP should still have a TPS and use it along with the ECU software and the ECU itself to implement transient enrichment (snap acceleration) strategies and other clever tricks too.

[ChimpOnGas]

SILICONEKID 357HP said:

So what am I loosing out on ?

Will mpg be effected ?

So you do (or dont) have a MaP sensor Daz

[ChimpOnGas]

SILICONEKID 357HP said:

Maybe I ask too many questions

Not really Daz, in this case your question helped me learn some new stuff from spitfire4v8

The post from spitfire4v8 was really interesting and informative, there were a number of points that (when I really thought about it) made a lot of sense to me

The way I see it we should thank him for taking the time to share his knowledge, and you for asking the question that stimulated his response.

[ChimpOnGas]

ianwayne said:

I have Canems fitted and had my laptop plugged into it this morning, partially due to the revs being very slow to drop to idle under no load. I resealed the plenum and don't think I have an air leak. I thought maybe the TPS output was incorrect but it isn't.

Anyway, my manifold pressure is 38 kPa at idle immediately rising to about 90 kPa with throttle opening (warm engine). There is an outlet pipe in the stepper motor housing used for the sensor, at least where the stepper motor used to be.

Standard 4.0 engine and cam.

Edited by ianwayne on Sunday 30th September 12:17

Hi Ian

I was forced to disconnect the idle air control valve on my Canems system because it was causing the priming pulse to constantly loop, with the key on in position one and the idle valve connected... the fuel pump will buzz - stop - buzz and just keeps cycling like that over and over until you crank the engine, obviously like this the Canems system is also dosing the inlet manifold with fuel every time I hear the fuel pump buzz which at best means a flooded engine and at worse... well lets not go there!

It shouldn't do this either



And the above without me even touching the throttle, it would be nice to think I've created the first Rover V8 that will rev to 26,785rpm but the truth is it was cold cranking at 300rpm tops!

As soon as the ECU sees a engine cranking signal or the engine is running I believe the looping issue becomes a non-issue, but my Canems ECU most definitely shouldn't loop the fuel pump & priming pulse with the key just sat in position one (ignition on), what it should do of course is run the priming pulse strategy for a second or two then turn it off.

The thing is this is my fourth (or is it fifth) Canems ECU, and none of the earlier versions did the looping priming pulse thing, nothing has changed with my car's wiring since I fitted my latest Canems ECU, the only thing thats changed is apparently my latest replacement ECU came with the new supposedly improved more sensitive crank sensor arrangement, MORE SENSITIVE being quite the most laughable understatement!

The outcome being (for whatever reason) my new ECU just doesn't like the idle valve anymore.... or the rad fans for that matter as they've been proven to stimulate the priming pulse too if the engine is hot enough for the fans to chime in when you switch the key to position one...

It wouldn't be so bad, but the priming pulse circuit on my car is also responsible for my LPG safety solenoids, so with the idle valve connected the solenoids are effectively permanently open and the injectors permanently open which just floods the plenum and inlet manifold with explosive LPG, clearly this has potentially deadly consequences so you'd think the ECU manufacturer would be keen to help... but sadly it seems he only answers my emails when I send him a good news story

I've recently reached out for help from him but the silence is deafening, Lloyd Specialist Developments did try to sort it out and made it a little better for a short while but in the end the only way I could stop the looping issue and make the car safe was to disconnect the idle air control valve, yes that's right the very same idle air control valve the Canems system is designed to control, a fact that would be laughable if it wasn't so damn dangerous!

Now for something that may help everyone with a Canems system!

After disconnecting the idle air control valve which I was clearly forced to do for safety reasons, the car ran noticeably better than it ever has, the only disadvantage seems to be I now need to tickle the throttle on cold starts and hold the revs up to save the engine from stalling for the first 20-60 seconds (depending on ambient temps) of cold start/warm up.

This is much like others describe they have to do with their MBE systems that like my current Canems setup also does not have an idle air control valve, the drivability and idle stability improvements I'm enjoying since disconnecting my idle air control valve clearly suggests the Canems system has never controlled my idle air control valve properly.

Or perhaps it's the fact Lloyd Specialist Developments keep the cost of their Canems conversion down by choosing not to use a genuine Bosch made idle air control valve?.... Either way.... for drivability and more importantly for me safety reasons I am now forced to run with no idle valve at all, obviously this is a less than ideal situation but as the manufacturer hasn't even had the courtesy to respond to my email I guess that's the way it must stay

Try your Canems equiped TVR with the idle air control valve disconnected electrically and seal it's air feed too as I discovered at rest the valve isn't actually fully closed so the engine can always draw air from that path which is counter to everything I was ever taught about setting an engine up properly as basically it's just a vacuum leak which is a classic no-no when tuning for a smooth idle and good low speed engine behavior.

Admittedly I was professionally educated on carburetor tuning (and a bit of K-Jetronic), but the basic rules of engine tuning are just the same on carbs as they are on injection.. ie ALL VACUUM LEAKS ARE TO BE ELIMINATED WHEREVER POSSIBLE!

I don't care what anyone says, an idle valve that still remains open even after you no longer need it's extra air bleed to maintain idle speed is a bad idea, it seems what you get with the fake Bosch valve you get with the Canems system is not a small bleed either, in my case it's actually huge, the kind of big ol vacuum leak the old boys who taught me carb tuning would have beaten me for missing

I also think before all my priming pulse looping woes the Canems system wasn't controlling the pattern part valve properly anyway, either that or the installer needs to consider using a genuine Bosch item, in closed loop fueling mode the ECU makes a pretty good fist of hitting the AFR targets and compensating for the inconsistent air bleed caused by the errant behavior of the idle air control valve.... but it's essentially always working at ten tenths to do so as the system is effectively fighting itself!

The bottom line is from what I've witnessed on my car and those of others running the Canems engine management system too, you are way way better off unplugging the dubious quality pattern part idle valve from the Canems ECU and blocking the valve's air supply too to create a proper old school sealed system...well as near as you can with the essential crankcase ventilation system such as it is.

Edited by ChimpOnGas on Sunday 30th September 19:00

[ChimpOnGas]

I don't mind a bit of off topic Ian, I'm the OP after all and actually there are links between what the idle valve is doing and MaP.

For the record the priming pulse feature runs your fuel pump and at the same time opens your injectors to wet the inlet manifold, however it will only do the injector opening element below a certain coolant temperature threshold that you (or your installer/mapper) has set using the Canems software. Of course my looping priming pulse is a fault, this is the point of my last post along with expressing my dissatisfaction with the ECU manufacturer who has failed to answer my email asking for help to resolve the issue, which is clearly a fault unique to my latest replacement ECU by the way.

I'd treat any pattern part idle valve with suspicion as they are not made to anywhere near the standards one might expect from the genuine Bosch article, I've seen them fail before and when they do they rattle like a child’s toy. When they fail the valve becomes very unpredictable, manifold vacuum which is a very strong force can act on the failed internal mechanism allowing the engine to draw way more air than the ECU is telling the valve to bleed in, this may well be your high idle fault.

The ECU manufacturer is very aware of my looping problem BTW as it came with the fifth replacement ECU he sent me in September last year and the issue was discussed extensively with him then, sadly I'm now left in a situation where the installer is either blaming their customer for my innocent misfortune or the manufacturer himself which is comical as they both work hand in glove, the manufacturer's response to all this being silence.

Of course after much fighting my point, it was looked at free of charge by the installers earlier this year, but not before I was told I needed to pay them some £600 to rewire my engine management system, this from the same installers who wired it in the first place! Sadly they failed to fix the problem which continues to this day if I reconnected my idle valve, good job I refused to pay the proposed £600 for that fix!

The truth is I've had multiple Canems failures over a five year period that averages one catastrophic failure and replacement system every 12 months, during this long period I did not reveal the issues to the TVR community as I wanted to give a chance for the manufacturer and installers to get it right.

Five years of consistent failures is a long time, it’s also a long time for a paying customer to maintain their patience, and clearly there comes a point where my generous and extremely patient approach has to end and the system should just work as advertised. In this case the tipping point came with the fifth replacement ECU that while working brilliantly in every other respect still presents a fault, I should add the looping priming pulse is a new and different fault from those before and this time is one that has safety implications.

I'm a reasonable guy, I’ve also been a dedicated promoter of Canems and the installers on these pages too, and probably the best free salesperson they ever could have dreamt of, so to be frank you'd think the support would be better.

Of course everyone has their limit, even me! My patience and optimism has run dry, the bottom line is if something doesn't work as advertised the customer should be properly supported. He most certainly should not be told the issue is of his own making and he definitely should not be asked to pay £600 to rewire the loom by the very same people who created and fitted the loom in the first place.

To be clear though, I do not believe the issue is with the wiring at all, the issue to my mind resides within the latest replacement ECU, it seems highly likely this example was simply not correctly shielded from EMI when it was built. It is my belief based on much clear evidence that manufacturer left something out of my latest replacement ECU when he built it, something like a diode or a zener diode that relates to the ECU’s ability to resist the effects of electromagnetic interference.

At this point I should share that this would not be the first time something has been left out of one of my many replacement ECU’s, on one occasion I discovered the manufacturer forgot to fit the ceramic heat pads following yet another Canems failure. Obviously that ECU blew itself up too as the ceramic heat pads are essential to take the heat generated by the injector drivers inside the ECU and transfer it to the large aluminium heat sink plate the installers screw in the passenger footwell.

With no ceramic heat pads fitted catastrophic failure of the delicate injector drivers was inevitable, the pads are a fundamental element of the ECU design so how and why the manufacturer and designer himself was able to forget to fit them is beyond me? Leaving the pads out also raised serious questions over the consistency of work and attention to detail, both absolutely essential elements fundamental to the quality manufacture of electronics.

And as it turns out the ceramic heat pads aren’t even ceramic as advertised anyway, they are aluminium with some kind of anodized coating on them designed to insulate the drives from shorting out through the pad as it pulls all the heat they generate away and into the heat sink. I have had countless injector driver failures in the last 5 years, looking at these pads and their micron thin anodized insulation coating and the way they interact with the aluminium heat sink plate it is highly likely my failures were the result of the coating rubbing off the pads through vibration so causing a short circuit and frying the delicate drivers.

With all the above facts in mind I’m currently finding it difficult to continue to recommend either Canems or the installers until at which point they do the right thing and resolve my latest issue of priming pulse looping, which is definitely not of my making. It's a shame really as the system has such potential, the software is incredibly easy to use and the 50mpg plus I get from running LPG is game changing, if only all this could be matched by decent reliability and customer support it would be a truly brilliant thing.

[ChimpOnGas]

It's not so bad Matthew.

The car runs beautifully all be it now without an idle valve, which in practice is only an issue during the warm up phase, I can solve that easily enough with a cable controlled extra air valve which can't possibly make the ECU loop.

I guess I'll be going back to my vintage car days where a fast idle lever worked brilliantly, I'll use my brain as an ECU like we did back in the oldun days, I have a simple brain but for sure there are no EMI issues with it

Sometimes the simple is best, although I really shouldn't be forced to go backwards with these things

[ChimpOnGas]

Interesting solution lancelin, kinda an electric version of my manual idle valve solution

Clearly a few Canems users are suffering idle air control valve issues

[ChimpOnGas]

ianwayne said:

Lloyd developments have got back to me. Apparently, they did have a bad batch of aftermarket idle control valves but for the last few years have only used Bosch. For the price of postage, they will test mine and replace it if it is defective. And it's over 2 yrs old so that is a very good response. If I can't establish an air leak anywhere else, I will do this.

Sorry to hear that the Canems aftermarket has gone a bit sour. Aside from my high idle speed, it's still great on my Chimaera. Accelerates smoothly and starts first time hot or cold.

Hmmmm, mine is definitely an old pattern part thing that came with my early Canems installation, no genuine Bosh idle valve for me

However, my issues run deeper than just the make of valve

In my case it's quite clearly an ECU shielding issue, what I'd like to be offered is a replacement ECU to test this theory, if it solves the problem as I suspect it will I'd then then send my faulty ECU back and keep the working unit which would mean 30 minutes down time for the car not weeks at Lloyds only to get it back with the exact same fault..... as happened with the last attempt to fix the problem.

An exchange dual fuel ECU is surely a perfectly reasonable request? After five years of failures I've certainly become quite adept at pulling them out and fitting the next improved version.

Every time I suffer a failure it ends in me being without the car on LPG for weeks and weeks, fortunately following the first ECU failure while I was touring France in August 2013 I was sent a petrol only ECU to get me back to the UK, over the years this ECU has kept me rolling on many many occasions, I call it my 'Petrol Only Get Me Home ECU' and keep it in the car at all times along with the tools I need to fit it at the side of the road.

• MARCH 2013 - ECU FAILURE No 1

• JUNE 2013 - ECU FAILURE No 2

• AUGUST 2013 - ECU FAILURE No 3

• JANUARY 2016 - ECU FAILURE No 4

• AUGUST 2017 - ECU FAILURE No 5

On each occasion I have to say I've been supported, usually by being supplied a replacement ECU, the latest one sent to me in September 2017 has so far proved itself to be reliable, sadly though it came with the new fault of looping the priming pulse feature, the installer told me I needed £600 of rewiring work which I found odd as the ECU was wired by them in the first place

Then it failed again, at which point I was quizzed with great suspicion on the LPG injectors currently used as I was clearly being suspected of bringing injector driver burn out issues on myself by fitting different injectors, they of course were the Hana injectors fitted by the installer themselves although I did recently discover they pinched an injector wire when installing them which they have now put right. I was also told the looping was probably my fault as I'd fitted a small electric water pump which was likely generating EMI issues, again I was able to prove the installers fitted that pump themselves as I'd fortunately retained the invoice and emails relating to it's installation. In any case how is it I've had at least three other Canems ECU with that little water pump in place and none of them caused the looping, and how is it if I go outside now and fit my old get me home ECU there will be no more looping too (I've proved this over and over again).

By this time being accused of bringing all these recent issues myself was starting to get up my very patient nose, and I was getting weary of producing evidence to the contrary, after all this and a stream of backwards and forwards exchange of emails the installer finally agreed to the car back to fix the latest failure which turned out to be all the gas building up in the plenum caused by the looping priming pulse had literally blown the MaP sensor hose clean off the back of the plenum... caused by pure pressure not an explosion thank God!

With the little hose reinstated the route cause was investigated which was clearly the looping priming pulse, so the crank signal earth wire was moved from the battery where the manufacturer had wrongly told me to connected it and was relocated to the engine block/cylinder head where it should have been. I was then told the car was ready for collection, I was clear to challenge it really was ready and fixed before taking time off work and making the long journey to collect, I was reassured it was.

Sadly when I arrived while the car was running it was not running well at all and the looping priming pulse was soon to raise its ugly head again, clearly after having the car for three weeks it was far from being fixed. I remapped the system and ditched the idle valve altogether at which point not only did the looping issue disappear but the engine ran noticably better than it ever had which leads me to believe that pattern part idle valve had never ever worked properly. This all brings us neatly to where I'm at now, the car is running brilliantly but if I reconnect the idle valve or the rad fans chime in with the key in position one.... the priming pulse will loop!

I dont think the installers are in a position to fix my faulty ECU, they are not ECU or electronics engineers, only the manufacturer can help which would be fine if only he would answer my emails and phone calls, I'm sure if he took a look at my latest replacement ECU he'd find the fault in no time, but it seems quite clear he filters his emails and calls

To be honest I'd far prefer it if my Canems system didn't keep failing and throwing up EMI looping faults in the first place, but as we can see from the above list of failures it's been rather problematic over the last five years so I'm now very concerned the manufacturer is winding down his business.... which in reality wouldn't make much difference for all the response I'm getting from him these days

Edited by ChimpOnGas on Tuesday 2nd October 00:18

[ChimpOnGas]

ray von said:

Blimey that's a tale of woe, bet it's not up here much longer
I must say though you've been an advocate of this system for years and sang its praises to anyone who'd listen/read your very detailed posts and yet all this time you've had nothing but bother with it. I will stand corrected if you have indeed mentioned it but some of your posts are very long so I could've missed it

I've always accepted the dual fuel ECU I have is something different, I understood there were some development rough edges to be knocked off as I went along. I should also say there are always details that sit behind these type of stories that may or may not have had an influence on reliability. I'm referring to the early use of low Ohm Keihin LPG injectors, although no one ever said or I suspect even knew they may cause issues as the manufacturer kept on testing the ECU with these injectors and declaring it fit for service.

Unfortunately the Keihin injector issue has been proven to be largely irrelevant now as I've suffered at least two injector driver failures on the ECU safe 1.9 Ohm Hana injectors. Fortunately the ECU for now is not burning out it's injector drivers, I've had a year of service out of it in this respect so I'm praying I've past the dreaded driver failures that have plagued my Canems dual fuel experience for may years and left me stranded a number of times.

But while the latest ECU seems robust so far in respect of driver failure it frustratingly came with the new fault of looping the priming pulse over and over again if the idle valve remains connected. Lloyd Specialist Developments have always tried to help but getting a response from David Hampshire of Canems is a bit like catching smoke

To be clear many electrical components cause the looping issue with this latest ECU, the idle valve, the radiator fans ect ect all stimulate the looping fault. Obviously the rad fans and the idle valve are integral components to the correct functioning of the car so we need to move on from blaming them, clearly the ECU should be able to cope.

All the many other ECUs I've had never ever displayed this looping priming pulse issue, if I plug in my petrol 'Get Me Home' ECU today it will not cause the issue either, and sadly Lloyds kind efforts to relocate the crank signal sensor wire earth did not solve the problem either.

Thanks to Lloyds I now have the right wiring to match my latest ECU but the ECU still loops the priming pulse, I now think we need to accept the problem is not with my wiring, electric water pump (now removed completely) or any other electrical component.... The issue to me clearly resides within the latest replacement dual fuel ECU that David Hampshire sent me in September last year.

Based on this evidence it seems clear to me the looping problem is a fault inside the latest replacement dual fuel ECU, or more specifically something that's not inside it. Just as David Hampshire left the heat pads out of one of my many replacement ECUs causing yet another injector driver failure I strongly suspect he also forgot to add a component that is responsible for shielding when he built my latest one.

Understandably I can not afford any more down time with the car due to Canems ECU issues, so I've asked Danny Lloyd if he could loan me a new and tested dual fuel ECU to try? Within the 30 minutes it takes me to swap the ECUs we would have our answer, this could all be done by post which seems a far more logical approach than sending the car away and losing it for weeks on end again.

My bet is as soon as I fit the new dual fuel ECU the looping with completely disappear, I have emailed David Hampshire a few weeks ago now asking for help but as normal he's ignored my message, and I know he checks his emails because last year when I sent him an email to say the car was running well he answered within 24 hours.

I'm now at a complete loss as to what to do so can only turn to Lloyd Specialist Development for support.

Despite the many failures I've suffered in the last five years of running the Canems dual fuel system I'm of the optimistic opinion all my injector driver failures are behind me, this makes the looping priming pulse even more frustrating as I can't help feeling the system is finally close to being perfected on my TVR.

Dave.

[ChimpOnGas]

For the record I had issues with my Canems fan output, it seemed to pulse one of the fan relays installed up front on the N/S inner wing when I had the Canems sytem fitted some six years ago, the contacts would chatter and like this the same fan relay every time would last roughly 3 months before burning out it's contacts..... the failures were reapeated over and over which was getting expensive!

When the relay burnt out it's contacts would weld themselves shut so the fans would run continiously, this had the very real potential to drain my battery in short order but I was more concerned the issue may end in a fire risk so a solution needed to be found, my fix came in the form of a Divies Craig fan controller.

https://www.pistonheads.com/gassing/topic.asp?h=0&...

This was back in March last year and since then the Divies Craig fan controller has worked faultlessly, taking the fan control away from the Canems ECU proved to be a wise choice, after fitting my new stand alone fan controller I never had a days trouble and all my relay burn outs ended instantly.

On a seperate note I'm not keen on an electrcally controlled extra air valve however it's triggered because it will highly likely trigger my priming pulse looping issue that no one seems to be willing or able to help me fix once and for all My best option is probably to create a manual idle valve which I freely admit is a laughable solution when talking engine management, but failing any support to fix the issue correctly I guess thats all I'me left with

[ChimpOnGas]

ITVRI said:

5 ECU failures in 5 years must be very frustrating. I’m curious to know do they refurbish/repair the orginal ecu each time or swap for a brand new one?
If they are swapping for a brand new ECU (and assuming other people are not having similar problems) then in my mind it would point to a fault outside the manufacturers control.

I think 5 years on from the original purchase (especially electronics) the manufacturer has likely reached the end of his good will and like anything as a consumer you either cough up for the new model or buy another brand.

To be clear in each case I have been supplied a new ECU, the system was originally wired by the installer and that wiring has been tidied up by them on two occasions since the first install, once I should add at a considerable cost to myself which was gauling but I sucked it up in the hope that better reliability was at the end of it all.

On the second wiring tidy up the car was taken back by the installer a few months ago and the work was done FOC, sadly although I was told it was fixed the looping priming pulse has continued all the same so I think you'll find after five years and five failures my friend, the only person who has any right to run out of good will is me the customer!

With any complex box of hand soldered electronics there will always be room for mistakes, the way to build reliability into something like an ECU is to design a schematic on a computor and send the files to a large scale electronics manufacturer for them to build your boards with repeatable quality on a big expensive modern machine in a proper clean room manufacturing facility.

You just can't replicate that level of repeatable quality manufacture in the shed at the bottom of your garden hand soldering everything together yourself as a one man band engine management company, it's such a shame Canems operates like this because the design, ideas (dual fuel ECU) and the software David Hampshire came up with is fundimentally outstanding.

If only he would just email his schematics off to one of the super high tech facilities in Hungary which is now the European hub for the very latest technology electronics manufacture. Any number of these high tech Hungarian facilities could produce what they would see as a laughably simple box of electronics to a very high standard, and it could be done for very little money.

This is how the better Eastern European LPG ECUs are produced and in many ways they are way more complex than a Canems ECU, the quality is typically first class and you can buy such ECUs for £150 as a consumer proving just how much profit is made on the after market ECUs used on our cars.

No one making ECUs should be hand soldering their product these days, it's redicuolously time consuming and ultimately completely unnessesary, but most of all it's a process that leaves your product massively open to human error during fabrication which I believe is likely where things have been going wrong for me.

[ChimpOnGas]

spitfire4v8 said:

Try installing the N/C relay into your fan control circuit and see if the priming pulse issue remains or whether it's operation returns to correct. If so you can still use that relay to power your extra air valve. You can get relays with quite high resistances and flyback diodes. I'd recommend something in excess of 70 ohms coil resistance anyway. Worth a thought.

If the fan control (as in the temps and the on/off operation) were working to spec, and it was just that when switched to ON the relay chatters then you could try a delay off relay with the time set to much longer than the chatter frequency, ie several seconds.

Thanks for the tips, but I'm trying to move on to sort the looping priming pulse issue now, the fan issue I solved with the Davies Craig stand alone controller. Other than my manual idle valve arrangement needed because I've now had to remove my pattern part idle air control valve I'm not keen on touching the system for fear of again being accused of bringing issues on myself as I was with regard to my little electric coolant pump.

I've asked the installers for another dual fuel ECU to try which I think is reasonable, as the original installers wiring has been looked at and tidied up by them on two seperate occasions now and pounced fit for purpose, and because the electrical elements that cause the looping like the idle valve are part of the very system they installed I think it's only logical and fair to assume the issue resides within the latest ECU.

This theory is even more compelling when you consider none of my other Canems ECUs presented this fault, so a quick try of a 'known good' dual fuel ECU is surely not an illogical or unreasonable request?

Within minutes we'll know if it is indeed an ECU fault as I suspect, or something else that needs investigating.

Edited by ChimpOnGas on Tuesday 2nd October 15:14

[ChimpOnGas]

spitfire4v8 said:

All understood, was just thinking of work-arounds for you but as you say it shouldn't need it. I wish you well and hope you reach an agreeable resolution.

Many thanks, I do appreciate your support.

The installers are decent guys and safety issues asside the looping priming pulse isnt the end of the world, I'm sure there's a simple fix but I do suspect we'll need the help of David Hampshire to finally get to the the bottom of it, it's just a shame he's so hard to get hold of which forces me back to the installers.

I think it's possible something like a diode got left out of my latest replacement ECU, but it could just as easily be that a component is not working correctly and needs replacing. The looping pulse might not necessarily be EMI related at all of course because my understanding is most EMI problems can usually be solved with screening of cables or optical isolation. There could be conducted power supply noise on the line or even a bad solder joint on the PCB which I'm reliably informed can cause intermittent problems like this, ast this point we should always keep in mind David Hampshire hand solders his components.

As I keep saying the system currently works brilliantly in all other respects, yes I've had a long history of failures but the period where injector drivers were failing repeatedly (even on the safe as houses 1.9 Ohm LPG injectors) does seem to have passed.... well for now at least.

Lets see if I can get a new ECU sent over which to my logical mind will conclusively prove if the issue is indeed ECU related or not, and I'll go from there.

Thanks again, Dave.

[ChimpOnGas]

Sardonicus said:

It is however the onus of the installer to chase up this Mr Hampshire Dave example scenario ....... if I fit a DSG Mechatronic unit to a Golf/Audi for example and it fails or develops a fault its my responsibility to deal with the VAG dealer or VAG uk direct and NOT for the customer direct , I feel they should be doing more and quite frankly I would want a customer with issues out of my hair rather than eating my dinner at home and mulling over how I can aatdeal with this customers issue or on going problems I would want to move on You may need to stamp your feet harder

Simon, you have to appreciate I've needed to approach this from both angles as David Hampshire diectly supplied me the latest ECU that came with the looping fualt.

We are afterall just talking about a plug and play box of electronics than can easily be posted, this 'post me a replacement' system has worked well in the past including when I was left stranden in the South of France on 5 cylinders. So if ithe post it system works with over 1,000 miles between me and the manufacturer with the French postal service in between, it shouldnt be an issue from one UK address to another right

To me the resolution to all this is no more complex than someone popping a replacement ECU in the post to me, I don't really care who posts it, I just pray for a new ECU to try which I really don't feel is an unreasonable request.

If it turns out to effect no improvement I would of course pop it straight back in the post to either David or Lloyds, whichever kindly sent it.

In the face of complex issues its often best to stop, take stock, and adopt the simple approach.... in this case we just need a new dual fuel ECU and a helpful postman, so how hard can it be

[ChimpOnGas]

Sardonicus said:

air enough moving forward I agree you need to be sent a replacement ECU

And 10 minutes ago I was informed one is on its way Simon!

I have just been informed I can expect to receive my new ECU early next week.

This may have looked easy to some, but trust me it wasn’t.

I am grateful the installers and the manufacturer are back to supporting me properly.

Dave.