Need a K sries engine diagnostic in Otago

Need a K sries engine diagnostic in Otago

Author
Discussion

Richard Gee

Original Poster:

201 posts

214 months

Thursday 24th August 2006
quotequote all
Anybody know a top notch engine diagnostics place around Otago anywhere? Car is very poorly. I have that lotus mechanic who posted on here coming over next week hopefully to take a look, but without knowing what is actually the problem - seems like it will be tricky to solve and I would like if possible to find somewhere where it can be plugged in to some clever geeky gadget which says 'Mister, you're coil is knackered' or something along those lines. The words "straw" and "clutching" spring to mind.

Here's a post from the other forum I use. There is video of the engine misfire too :-)

SICK CAR - HELP

OK – the story so far:

• Car was running fine in the UK
• Car was shipped to NZ (four week journey)
• Car was running fine when it came out of the
container
• Car ran fine for about two hours – then low speed/low revs misfire set in
• Stopped car, twiddled with HT leads, car fine
• An hour later, misfire returns, looked like one of the Magecores had broken, so I botched it and it went fine for another hour until we got home.
• Car sat in garage for a week, then was driven. 20 minutes into drive, misfire returns
• Magecores replaced – car fine for 20 minutes or so then misfire returns
• Since then – new plugs and dizzy cap and ECU reset – but still the same

So the misfire seems to have been introduced by the roughish roads of the South Island and seems to come on when the car is driven for about 20 minutes, though today I ran it for 20 minutes before I left…exactly the same thing. No problem while it was idling being blipped on the drive, then a few miles into the drive, cough splutter again after being fine initially.

When it is playing up, it ‘seems’ to idle OK and once you are past 3500 revs is *much* better, though it still doesn’t seem perfect. The part in between – circa 1000 rpm to 3500rpm it’s like you are not pressing the throttle at all, though occasionally it will splutter a bit and pick up as normal. So I am now wondering is there may be some crap in the injectors or a problem with fuel?? – as it appears to be getting a spark to every plug and I *think* I have changed the usual suspects.

If you have a look at the video – with the speakers turned on, hopefully you get the idea. I am holding the throttle open a tad, and it kind of goes, stops, goes, stops etc with metronomic regularity (why I thought it might be electrical). And this was after it had stood for ten minutes after a drive – it is much more “coughy” when it had been driven. The only other things I think to mention are that when driving it back home having turned round every time the misfire appears, you do get the occasional pop out of the exhaust, which it doesn’t do normally, and after I filled it up when I got it off the container – it seemed to take absolutely ages before it went from ‘full’ to that first number, I think it’s 35 litres, but was fine after that.

Other than that, it has been bullet proof for the seven years I've had it and the two years since Dave Andrews fitted a 150 head. No HG problems before or after that, and no history of being unreliable…. Help


Putfile link: http://media.putfile.com/Misfire-88


And some stuff I added today after tinkering with it, bleeding, getting burned etc.


SICK CAR - HELP

OK - an update after a day of tinkering and calling Lotus people in New Zealand.

I used Andy R's check list first.

1. Lambda sensor - not this. Did the disconnection thing, reset ecu, went for drive, misfire returned

2. TPS - disconnected this and although the car didn't like it much at all, it made no odds to the misfire, it was still there when the revs finally picked up.

3. Crank sensor. Cleaned and checked wires, disconnected and reconnected it as advised. Misfire returned. Tried disconnecting it fully. Engine wouldn't start at all. So 'not sure' about this one.

This was basically all I could do having cleaned the terminals and put a night's charge in the battery (which is only a few months old, though it is not out of the woods yet as a sucpect). So I spent some time trying to understand it a bit more. Here are some more symptoms:

a) Comes on after almost identical periods of time being DRIVEN

b) Start engine and let it run for half an hour so until it gets very warm (fans activated). Made no odds, ran perfectly for the first 2/3 miles then misfire returned.

c) Drove it with the misfire for about half a mile. Stopped and truned engine off for about 20 seconds, turned it on and it was fine, for another 2/3 miles. The engine bay would have been hotter after sitting for a few seconds, so I don't think it is the coil - though I have no way of testing this.

d) If you turn it off and then back on instantaneously, the misfire remains. Leave it for about 20 seconds and the thing runs fine for almost exactly the same period of time until the misfire arrives.

c) gentle driving or hard driving seems to make no difference to the time it takes for the misfire to return.

d) When it is misfiring, if you put your foot down harder than you would normally (let's say roughly the same kind of level you would use to overtake) - no matter what the revs and no matter what the gear - it runs normally.

e) There is a 'dead spot' where if you find it with the throttle, there seems to be no life at all - a little less and it kangaroos, a little more and it kangaroos. Find the same spot and stomp it, and it accelerates normally.

f) Chatting with the Lotus guy down here, who I think is very knowledgeable, he said after hearing all of the above that the MEMS may need reprogramming - something to do with a 'misfire' programme that will not be reset when you do the five presses on the throttle ecu reset routine.

As he is 400 miles away, is there any way to be SURE of this without plugging it into the diagnostics, it's a long way to go if it isn't the problem....and a long way to go for the sake of a 10 minute reboot. If it's 90% or more liekly to be the ECU, I'll get an Emerald and do it myself.

As also mentioned, there is a Lotus mechanic around in Queenstown next week who has said he will come and have a look at it. If you were me, which parts would you get shipped pronto for him to fit and see if it makes a difference.. I was thinking coil and crank sensor......?? His guess is the coil by the way, but I'm not so sure given the predictability and consistency fo the misfire. I also have a spare fuel rail if anyone thinks fitting that might make a difference, though I think a fuelling issue would be right the way through the rev range??

Cheers gurus.

Richard

As a footnote, New Zealand is clearly having a positive effect on me. Time was when I would have taken a hammer to the barsteward and blamed the cats. I've just been enjoying tinkering with it and have only been mildly disappointed every time I have tried something and the misfire has returned.




htsd

263 posts

241 months

Thursday 24th August 2006
quotequote all
Dodgy fuel pump power wire connection? Dodgy fuel filter? Diagnostics 101, an engine needs air spark and fuel to run. Sounds like air and spark aren't a problem so I'd be inclined to go after the fuel system next.

Esprit

6,370 posts

284 months

Thursday 24th August 2006
quotequote all
Mine did a similar thing once... just all of a sudden lost some high RPM power, and although it idled, the moment you touched the throttle it hunted for revs and then was very hesitant and down on power and very "touchy" on the throttle. Think it was the IACV playing up... I reset it with the five presses on the throttle thing and it never happened again. It wasn't long after I'd changed to the 160TB so that may have had something to do with it.

other things I'd be checking for:

Inlet air leak, possibly the gasket between the manifold and the head?

Another likely issue could be the Lambda sensor's fried as the engine will run closed loop at low RPM to help emissions, but when you're hard on the gas or high RPM it goes open loop and drops back to the ECU mapping.

Any of these seem likely?

Esprit

6,370 posts

284 months

Thursday 24th August 2006
quotequote all
Just read your footnote thingy.... ok, so it's not the lambda.... my money's possibly on an air leak, maybe a crack or something in the inlet manifold opening up when warm (you running standard plenum or alloy plenum?)

Possibly could be a sticky IACY, although you've reset it in the ECU, maybe the IACV is sticking when warm.... perhaps try pulling this off, cleaning contacts etc.?

iain a

329 posts

228 months

Thursday 24th August 2006
quotequote all
Hi

A mechanic friend gave me a copy of a magazine article titled "When the chips are down" by Chris Manton. Most mechanics don't understand electrickery so refer to guides like this.. There is a fair bit in the article.. but I copy below the main failure modes of engine management sensors, which may be a place to look.

Air intake sensor: "Check engine" light on, hesitation, strong exhaust odour, poor performance & economy

Crank angle sensor: "Check engine" light on. hard starting and poor drivability

Throttle air bypass valve: stalling surging, poor idle

EGR valve: poor or lumpy idle, poor fuel consumption, excessive emissions.

Fuel temp sensor: Poor hot starting and/or fuel consumption.

Water temp sensor: Poor performance and economy. hard starting or misfiring.

Manifold Absolute Pressure (MAP) sensor: Poor performance, black smoke, stalling, surging and cat overheating.

Well it is a few things to eliminate before you get to nasty things like ECU, coil etc!
Another suggestion is to do a search on www.blatchat.com/ - this is the Lotus 7 owners website and they have seen practically every fault on a K series.. the search engine is pretty good.
BTW how is the oil pressure?? had a problem with a friends Zetec once that was due to a sticking oil pressure relief valve. It pumped up the hydraulic tappets so they didn't close fully.. the symptoms depended on revs and oil temp as it changed the viscosity. Just a though.

Any Rover mechanic should be able to help you as the K engines in Lotus's isn't that different to the standard article - well up to the 190bhp VHPD anyway...

Good luck

Iain

Richard Gee

Original Poster:

201 posts

214 months

Thursday 24th August 2006
quotequote all
George, the cracked manifold is a good thought, but this morning I let it idle for half an hour on the drive to the point where the fans kicked in and it was hot under there. Engine was running fine, until it had been driven for a couple of miles. Misfire returned. Turned off engine for 20 seconds, drove another 2/3 mikles no problem, then it came back etc etc.

It's almost like the throttle has a dead spot when the misfire is there. If you just lightly press the throttle it kangaroos all over the place, no matter what the revs or gear. Boot it as though you were accelerating hard overtaking someone and it is fine. Or sounds and feels fine.... Wondering whether it is in fact not a misfire but something else completely cutting out the fuelling for that fraction of a second.

Thinking now towards

crank sensor
battery
coil
throttle potentiometer
IAVC pipes, wires and 'trap'

Or, worst case... ECU. Guess I could take out the ECU and get it couriered up to Ken to plug in and check. That would eliminate something major I guess, or find the problem if it was there. Can you diagnose the ECU on its own by plugging it in do you know?....

Esprit

6,370 posts

284 months

Thursday 24th August 2006
quotequote all
I'd talk to ken about it.

Hmmm I'll have a think about it, my suspiscions would lie firmly with the IACV or somewhere around there as it's only happening on part-throttle..... I'd be focussing my attention there for starters anyway.

iain a

329 posts

228 months

Thursday 24th August 2006
quotequote all
Hi

Throttle pot on my Duratech failed last year.. intermittant contact at low throttle openings which made it misfire and shunt like mad until you booted it. You should be able to find / eliminate that one with a Volt / ohm meter.. or better still an oscilloscope.

Iain

Kiwi XTR2

2,693 posts

233 months

Thursday 24th August 2006
quotequote all
I think I've worked out what's wrong.

Dean, Can you confirm this ain't a problem with Honda powered Elise's.

Seriously though I feel for you mate. I had a problem where the Westie would run perfectly for 10-15 minutes and then hic, hic, splutter, dead. After it cooled down it would again run perfectly for another 10 minutes.

It turned out to be a crank sensor cooking up. Replaced and never been a problem since.

Hopefully yours will also be a quick fix once the diagnosis is complete thumbup

Richard Gee

Original Poster:

201 posts

214 months

Friday 25th August 2006
quotequote all
Well, I've got a crank sensor winging its way to me now, as well as a new coil and a throttle potentiometer

It isn't the battery. I changed that and it made no difference. Something I did however DID make a difference!!

I took of the IAVC (inlet air valve control) and cleaned it up, it was pretty grubby, and the air intake temperature sender (the green one under the TB on a K series)

Anyway - when I went for a drive and the misfire returned (almost at exactly the same spot) but when it did return, it was FAR less aggressive and the car much more driveable. Instead of kangarooing it kind of paused for a second or two, then accelerated normally....

One thing of note, and I have absolutely no idea why this should be, no amount of letting it idle, revving the engine at standstill etc etc can bring the misfire on. It will ONLY come on when driving, and it goes after a 30 second switch off. I drove it with the misfire, stopped, restarted and drove about 50 yards home then sat with the engine going at different revs for at least galf an hour with it up to temperature, and it ran perfectly. So it does seem to me to be connected with motion!!!!

Might it therefore be something to do with air into the engine and ambient air temperature and pressure changing as I am driving around as it sucks it in under acceleration?

Seems odd that tinkering with the IAVC and the green sensor improved it, but did not cure it......

Esprit

6,370 posts

284 months

Friday 25th August 2006
quotequote all
I'd say if tinkering with the IACV/IAT altered it then it's one of these that's suspect.

I actually wonder if it's vacuum related... if it's Idling then the engine's at a pretty steady state, when you're driving you're on and off the throttle gearchanging/overrunning etc. When you're snapping the throttle shut, that's going to put pressure on the bypass (IACV) which may be causing this to perhaps lift away from its seat and give a bit of an air leak which causes the rough running. This will continue to happen until the ignition's turned off and the IACV re-homes itself. This means that once it happens, the IACV is then acting like an air leak which will cause the smptoms you've described.

go toa wreckers and pillage an IACV off an MGF... should be able to get it for $20 or so... job's a good'un

Richard Gee

Original Poster:

201 posts

214 months

Friday 25th August 2006
quotequote all
George - just emailed you after a conversation with Ken - see below:

Another discovery. This one is significant I think. I was chatting with the Lotus guy down here and described the above and he suggested disconnecting the vaccum pipe and checking that as Simon had suggested. So I finally pulled it out of the ECU and blew it. There was some dampness at the ECU end, enough that you could hear it 'cackling' as it came out of the end, but not a hell of a lot when I checked the end. No other blockages though.

He then suggested disconnecting the manifold to water trap vaccuum pipe and blocking it, then giving the car a run. So I blocked it as described, and left the other end disconnected from the ECU totally.

Hey presto - the misfire is instantly there on start-up....

Put things back as they were and it goes.

Remove pipes and it's back.

So what is it guys? Dead MAP? Therefore new ECU?

Richard Gee

Original Poster:

201 posts

214 months

Saturday 26th August 2006
quotequote all
FOUND IT!!!!!!!!!!!!!!!!!!!

At least I think I have. When I took the IAVC out the other day and cleaned it when I cleaned the TB, the missing/hunting whatever it was was less harsh afterwards. Today I took the bugger out completely and shoved a cork in the hole and would you believe it, she ran like a peach, for 20k - no sign of the problem and just a smoother engine really.

Also, the temperature was rock solid at 80/81, where for the last few hundred miles it has been moving between 78-82.

So, I think the IAVC has a fault which means it lets in air when it is not supposed to.


Question now is, do I bother putting another one in?


Sooooo - WELL DONE GEORGE - you were spot on and way ahead of some of the experts in analysing my drivel!!!

You win Taupo beerage at the A1GP :-)

Esprit

6,370 posts

284 months

Saturday 26th August 2006
quotequote all
Richard Glad I could help... or rather I hope it helps as this issue seems to be an odd one that's making you chae it a bit.... until you've fitted a new IACV and put a few hundred miles on it, I'd not start throwing babies in the air just yet

I'd stick with the IACV if I were you... it'll make the car run better at low speeds and it'll go a lot of the way to reducing engine wear when cold etc. I'd have a look at how much a new one from MGRover will cost... your local MG-Rover dealer will be able to tell you this. Alternatively you could contact "The MG Service Centre" in Christchurch (they're near Jade Stadium) The old bloke in there usually has 2 or 3 MGFs in bits for spares and I'd daresay getting a new IACV would be pretty minimal cost.

Alternatively you could contact "dejoux" on here (Paul) His father is in Dunedin and has/had an MGF as well as a T-series and is pretty in with the Dunedin MG club and I'd imagine he'd be a useful contact for sourcing another one locally.

Will be keen to hear how you get on. I had a similar issue with mine, but it happened once out of the blue and has never happened again, I've done maybe 3000 miles since.

Richard Gee

Original Poster:

201 posts

214 months

Saturday 26th August 2006
quotequote all
Been out for a long drive and it's as clear as a bell now. I'm certain that's what it was.

Did some digging around and some of the guys who primarily use the cars for track (Mine 'kind of' falls into that category, don't bother with the IAVC, and the Emerald doesn;t have to use it..)

All babies thrown :-)

Esprit

6,370 posts

284 months

Saturday 26th August 2006
quotequote all
That's good news Richard Glad I could be of (some) assistance.

I guess I'd be reluctant to let the IACV go, but then again my car's not as much of a GJOBer's car.... oops I mean track-focussed car as yours Above everything else mine's a road-focussed car that sees a bit of track time rather than the other way around.... when I've got an S1 Exige parked next to my liz in the garage, the Exige may take my GJOB/Track monster role

Richard Gee

Original Poster:

201 posts

214 months

Saturday 26th August 2006
quotequote all
Guess what?

Here's a clue

furious furious furious

Edited by Richard Gee on Saturday 26th August 06:47

htsd

263 posts

241 months

Saturday 26th August 2006
quotequote all
It wasn't the IACV?