Instructions to change fuel maps on 14CUX Griffith, Chimaera

[CGCobra]

Hi Mark

Thanks for that, I'll grab a copy.

[spikep]

Have check the voltage and it settles at 0.34v. Would not having a carbon canister in the fuel return affect it?

blitzracing said:

If its one of my 3.9 maps the white map is TVR unmodified, the green non cat map is the one I've worked on so I would not be looking at the map as the first point of call. Do you recollect why we where trying another chip? Its worth checking the AFM standby voltage, as if it drifts upwards the engine will over fuel. To do this put a test meter and Insert the negative probe into the Red/Black wire (sensor ground), and the positive into the Blue/Green wire (Airflow signal). Now turn on the ignition, and the voltage should spike to near 5 volts as the hot wire heats up, then settle to 0.3-0.34 Volts. I had not realised how important this voltage was with no airflow, but now i've had a few faulty AFMs to play with it has shown if this voltage is wrong, the whole output is wrong up the scale. Fuel pressure is another thing, if the vacuum pipe is not connected to the regulator the fuel pressure is too high. and so it over fuels.

Edited by blitzracing on Wednesday 24th March 18:16

[KiwiRRC]

KiwiRRC said:

stevesprint said:

If you do give the Aussie and Saudi fuel maps a spin let us know how they run.

Thanks Steve,
I really appreciate the help. Apologies for the slow reply - as a newbie I get blocked occasionally. Will let you know how I get on. I built a little rotary switch to swap between tune resistors. So far I couldn't spot a difference in the maps code - and haven't noticed a performance difference after a quick play. Might also borrow the original chip. And fortunately I live in New Zealand - so never that cold!

Cheers
Dave

Hi All,

I have managed to get my hands on a 2nd 14CUX to have more of a go with and I love how easy it is to swap in and out so have a few more questions.
1) It turns out I should have been using low compression R3362 and my RRC does have Cats!. Is there a file available for that for download.
2) A mate is looking to put a 4.6l V8 in his RRC running off a 14CUX. Is there a recommended tune for that?
3) Finally - if I really what to play - is there one of your racing tuning that pep up a 3.9l low compression V8? Or is that just silly?

Cheers
Dave

[stevesprint]

KiwiRRC said:

Hi All,

I have managed to get my hands on a 2nd 14CUX to have more of a go with and I love how easy it is to swap in and out so have a few more questions.
1) It turns out I should have been using low compression R3362 and my RRC does have Cats!. Is there a file available for that for download.
2) A mate is looking to put a 4.6l V8 in his RRC running off a 14CUX. Is there a recommended tune for that?
3) Finally - if I really what to play - is there one of your racing tuning that pep up a 3.9l low compression V8? Or is that just silly?

Cheers
Dave

Dave,

Sorry for the delayed reply and sorry I don’t have R3362, I’ve got R3360, R3361 and R3365 but not R3362, the Aussie map above was 3.5L.

I don’t have any low compression tunes and would be interesting to see the differences, do you have any? Maybe you should try R3652 http://www.remap-14cux.uk/bins/LR_R3652_3.9_HighCR... .

I’m not sure if you realise TVR Chimaera 450 are in fact 4.6 with 4L pistons to raise the C/R so your friend could use the standard TVR 450 map to get him up and running.

[KiwiRRC]

Hi Steve

Thanks for the help, it is much appreciated! I do have a copy of the latest operation pride tune on a chip so will give that a go. I should also have down loaded the 2666 tune originally on my RRC, that would be low compression. And I will follow your suggestion for the 4.6. Once again, thanks for the help!

Regards
Dave

[Bmanetd]

stevesprint said:

I’m not sure if you realise TVR Chimaera 450 are in fact 4.6 with 4L pistons to raise the C/R so your friend could use the standard TVR 450 map to get him up and running.

I've got 2 projects in the works right now. One is a 4.2L and the other is a 4.6L and both owners want to run 14cux systems with O2 sensors. Would your "TVR 430 Precat and 450 CAT based on LR R3652 with Extended Fuel Table to 6250RPM" prom be adequate for them? I'm assuming different tune resistors for the 430 and 450 maps?

Thanks!

[blitzracing]

I think the two maps are the same, so you don't use a tune resistor change. Dont forget an AFM based system is far more tolerant in dealing with different air flows, it will simply move to the correct point in the map if the engine breathes a bit more as long as you dont hit the top of the map airflow wise. The extended RPM mapping allows for drop off of volumetric efficiency as the engine struggles to fill the cylinders at peak RPM, so the fuelling is reduced per engine cycle. This give you every last available horsepower, but leaves no safety margin, as by default the map runs rich, so both cools the pistons and reduces BHP at around 6000 rpm.

[stevesprint]

Bmanetd said:

I've got 2 projects in the works right now. One is a 4.2L and the other is a 4.6L and both owners want to run 14cux systems with O2 sensors. Would your "TVR 430 Precat and 450 CAT based on LR R3652 with Extended Fuel Table to 6250RPM" prom be adequate for them? I'm assuming different tune resistors for the 430 and 450 maps?

Thanks!

Hi Bmanetd

For the 4.2 with CAT's I would suggest they run map 5 (white) with LR OEM http://www.remap-14cux.uk/bins/LR_R3384_4.2_1995_U...

4.6 with CATs they should also use map 5 (White) but try http://www.remap-14cux.uk/bins/TVR_R2967_450.bin as TVR 450 are in fact 4.6.

Good Luck and let us know how it goes.

Steve

[Bmanetd]

Thanks for the information! Very helpful!

Last question: Have you guys ever tried using the Moates 2Timer to have 2 separate tunes on 1 chip? I'm imaging it could be used to create a tune designed to maximize fuel economy and one used to maximize power and you could flip a switch on the dash while driving to switch between programs. Is it possible?

[blitzracing]

You don't need two maps to get the best of both world- simply make sure the mixture is lean under light load when you don't want full power for economy and rich enough at full power. Its a fallacy to think two maps are the answer. You could do one that leans off so much to make some nice noises in the exhaust on the over run if you want to call it your "race" map :-) , and one less extrovert for road use. Physically you can switch maps with a switch and tune resistor, but it does make the ECU throw a fault code to say the tune resistor is faulty but It does switch maps ok however. You dont need the Moats as you have multiple maps in the chip already just need to switch the tune resistor.

Edited by blitzracing on Tuesday 4th May 10:21

[davep]

Blitz, the Tune Resistor out of range fault must be flagged up when the tune resistor selection switch is thrown, giving an indeterminate sensing value. When such a fault occurs the code will select the Limp Home Map, Map 0, and closed loop fuelling.

So is it the case that when the Tune Resistor value is sensed again at some point after the switch throw the code selects the desired 2nd choice map but without resetting the associated fault bit?

Because of this I think the practise of live tune resistor switching is a 'bit iffy'. Have you road tested live tune resistor switching and confirmed that the map selection is correct?

[spitfire4v8]

Word of caution with running the moates full time. I did this for a cerbera customer as a way of getting multiple maps into the ecu, but the moates failed when he was driving the car .. the thought of that happening on a busy road or during an overtake made my blood run cold so I put that car back to a proper prom ..

the moates is an excellent tool but i use it only when i need to and i'm always mindful of that failure for my customer so never try any overtakes or anything that would put me or the car in danger should it fail whilst out on road test.

it might have been a one-off (and my moates i use for mapping has been super reliable and i wouldn't hesitate in buying another should it eventually ever fail, it's a great piece of kit) but i wouldn't run it on my car full time. I treat it as a mapping tool and nothing else.

[davep]

spitfire4v8 said:

... the moates failed when he was driving the car .. the thought of that happening on a busy road or during an overtake made my blood run cold ...

[blitzracing]

davep said:

Blitz, the Tune Resistor out of range fault must be flagged up when the tune resistor selection switch is thrown, giving an indeterminate sensing value. When such a fault occurs the code will select the Limp Home Map, Map 0, and closed loop fuelling.

So is it the case that when the Tune Resistor value is sensed again at some point after the switch throw the code selects the desired 2nd choice map but without resetting the associated fault bit?

Because of this I think the practise of live tune resistor switching is a 'bit iffy'. Have you road tested live tune resistor switching and confirmed that the map selection is correct?

You cant do it live for sure, but from memory if you turn off the ignition and throw the switch it changes as as it should, but logs a fault code in the process that needs a power reset clear if you dont have RG or ECUmate. It certainly does not stay stuck in map 0. The odd thing is I thought an open circuit tune resistor went into map 5 (being the nearest resistor value to an open circuit) as my car ran quite nicely whatever map it was running- stories about limping home never seemed to equate. Its possible map 0 is near enough not to be noticed, but Ill double check next time im abusing my ECU.

[davep]

I've gotten bored with the Moates, Tunerpro + RoverGauge approach, so I'm seriously looking at an alternative method:



Works OK on K-Jetronic, so 14CUX should be a doddle.

[stevesprint]

Bmanetd

You shouldn’t really need multiple maps as explained by Blitz but if required I would suggest replacing the 14CUX tune resistor with a rotary switch with soldered on resistors for each map, works a treat for me. You don’t need a Moates 2Timer.

Speaking from my experience, you can successfully change 14CUX tunes with the ignition off or the ignition on but not running and does NOT throw a tune resistor fault code. You can not change tunes while running which throws the tune resistor error on some proms, but not all, and stays on the current map, it does not switch to map 0 on any prom.

Map 0 is the default map selected without a tune resistor and not a limp home map, for example if a temp sensor dies the ECU uses a default value and stays on the current map. I can assure you a Precat does not switch to the CAT Map 0 when the AFM dies but instead the code estimates engine load from engine speed and throttle position.

I’ve had my Moates Ostrich permanently connected for the last 5 years and never missed a beat, I’ve even used it on a track day as I forget its there, however it is carefully secured behind the battery so it doesn't move around.

Dave, love the picture especially Mercedes on the typewriter, very funny!!

[davep]

stevesprint said:

....

Speaking from my experience, you can successfully change 14CUX tunes with the ignition off or the ignition on but not running and does NOT throw a tune resistor fault code. You can not change tunes while running which throws the tune resistor error on some proms, but not all, and stays on the current map, it does not switch to map 0 on any prom.

It did on this prom, running on Map 2 (open loop):



Open circuit on tune resistor I/P resulted in Map 0 (closed loop):

stevesprint said:

Map 0 is the default map selected without a tune resistor and not a limp home map, for example if a temp sensor dies the ECU uses a default value and stays on the current map. I can assure you a Precat does not switch to the CAT Map 0 when the AFM dies but instead the code estimates engine load from engine speed and throttle position.

It'll go to Map 0 if external RAM goes bad, since saved tune resistor value is/could be corrupted:

fuelMapNumber       = $202C ;*(R) this will be 0 through 5

Also, in the event of a MAF fault, the AFM fault substitution code calculates engine load based on throttle position and engine temperature. This calculation does use one of two separate routines and sets of values according to the Map Number selected, it's because these sets of values are exactly the same for open or closed maps that Map 0 being selected in the event of a failure makes no difference.

stevesprint said:

Dave, love the picture especially Mercedes on the typewriter, very funny!!

Steve, do you know if Lucas made typewriters? If not I'll have to get an Imperial instead.

Edited by davep on Monday 10th May 12:27

[TRIUMPHBULLET]

Hello all, its been a while since I was last here, I have been looking at Tunerpro files and xdf's, just to pass the time more than anything.
Does anyone know how the 'accelerator pump' functions, I assume it is via the throttle sensor but am probably wrong.
Also what is the newest/most complete xdf available now?
Thanks in advance.

[stevesprint]

Issac
How’s your supercharged Triumph TR7 Bullet?

Here’s a link to my latest TunerPro definition file dated 22/03/2020
http://www.remap-14cux.uk/TunerPro/TunerPro14CUXCo...
Please let me know if you need anything adding or fixing and I’ll do my best.

If you mean the one table ‘accelPumpTable’ in the data.asm then sorry no, however

I have got my head around the six row ‘throttle pot direction & rate’ tables in each map which are called in TunerPro “Map (1-5) THROTTLE TABLE”.

1st Row Temperature (hot to cold, left to right) only one column comes into play at a time
2nd Row Throttle Opening Max throttle fuel added
3rd Row Throttle Closing Max throttle fuel subtracted
4th Row Throttle Open Multiplier
5th Row Throttle Closing Multiplier
6th Row Throttle Opening extra fuel decay time

Setting the decay time down to 01 the extra throttle fuel does NOT decay below 4000rpm at which point this table is ignored due to the processor running out of time between sparks, therefore reducing row 6 increases the decay time.

This a very important function of the throttle pot which you can see with afr guage when the max is set to 01 the AFR goes very lean for a split second and the engine hesitates when suddenly flooring the throttle. The Bosch AFM I use has a quicker response time so I had to reduce this throttle pot extra fuel, I believe this throttle fuel could be increased to eliminate hesitation with cheap copy 5AM AFMs.

[CGCobra]

Hi All

Don't know if this it the right place to ask the following question but as this seem so be the focus of so many knowledge on the 14CUX I thought I’d give it a try.

Although I’m trying to get into this system I’ve been diverted off on an ignition system project to convert from distributor to coil-packs. One problem I’ve got is getting the signal from the 14CUX which normally comes from the single coil from multiple coils. I’m currently managing this by linking to all 4 coils through diodes and this works OK however I’d like to get rid of these if possible as they’re another possible point of failure and I’d rather not be using this ignition ‘flyback’ pulse, much prefer to ‘talk’ to the 14 CUX with a low voltage controlled signal.

I had assumed that the input into the 14CUX would be a high impedance (or high resistance to ground) however I examined the connection and found it’s actually 12v (without the 6k8 resistor) which blows my understanding of how this signal works.

Questions.
1) Is it correct that I have 12v on this terminal?
2) Has anybody else managed this signal from another ECU, if so how was this done?
3) Does anyone have a circuit diagram to pin 39 of the 14CUX?

The ECU I’m using has a transistor (or at least it did have!) which switches to ground with each ignition pulse but I could change/adapt this if necessary.

Edited by CGCobra on Friday 25th June 13:40