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bzguy

Stumbling engine - Troubles again :(

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I've been having similar engine stumble lately.

The cars had a new turbo, exhaust manifold, cat bypass and new through silencer, service amounting to a C service with all belts, fluids, plugs leads etc.

Car was fine for a while then started missfiring stumbling and zero power under load. No engine check lights though

I took the car to Sportomotive and they changed the coil pack, and it's a different car, more responsive, smoother drive.

Maybe you have the same problem, only trouble is, the coil packs aint cheap.

Check all the connections to the coil pack as well, mine were very corroded.

Just a thought.

Coil packs ARE going cheap on the factory clearance website...around


Proud recipient of the LEF 'Car of the Month Award' February 2008

"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming: "Wow, what a ride!!"

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Coil packs ARE going cheap on the factory clearance website...around
Edited by lrg_machine

Jez

Mean Green S4s

I think therefore I am - Descartes

I'm pink therefore I'm spam - Eric Idle

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Went for some other test drives again, remarked the following :

1st run : no stumbling, just once "heck engine light" on, less boost (degraded mode)

Before 2nd run, I re-installed the stock chip (instead of the current #3 chip), rook it for a run of about 50 km's : no problem at all !

I've read somewhere on this forum (article about test of SE) that there's a built in mechanism that the knock sensor will detect the onset of detonation and retard the spark timing when lower grade of fuel is used. Boost pressure is then reduced to ensure that the system doesn't cycle in and out of detonation.

Reminds of of having filled up my car the very last time (just before the roblems began) at another gas station that I used to do. Maybe lower fuel quality ? Anyhow, fuel ank is almost empty now, so next time I'll refuel again at my regular gast station.

Don't know if it will solve definitively the problem, but remarkably problems get less every run ... If no problems occur anymore, I'll switch again to the #3 chip, take it for a big run (what 's best to learn : highway or mixed roads ?)

In any case, I'll order an usb aldl - interface for freescan ... too bad about the wheather nnow, Esprit's are VERY addicitive :D

Thanx for all reactions, I'll keep you updated :D


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Did some testing again to sort out the problem(s).

First, changed the spark plugs, went for a 25 km test ride : car drove PERFECT : temps ok, boost ok, no problems at all !

Came back after couple of hours, problems started again :)

Good news : got my Frreescan-stuff today, so hooked up to the car, did a little testing (on idle, sometimes a bit of throttle to avoid engine going down)

I've uploaded the Freescan CSV fil, so if anyone can help me sort out the problem, I'd be very very very glad ...

CSV File

Any help is EXTREMELY welcome !

Thanx in advance

//edit : don't know anything about interpreting Freescan data, but I noticed some weird "Spark" readings ; strange, they're brand new (old ones were not black)

Edited by bzguy

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Did some testing again to sort out the problem(s).

First, changed the spark plugs, went for a 25 km test ride : car drove PERFECT : temps ok, boost ok, no problems at all !

Came back after couple of hours, problems started again :)

Good news : got my Frreescan-stuff today, so hooked up to the car, did a little testing (on idle, sometimes a bit of throttle to avoid engine going down)

I've uploaded the Freescan CSV fil, so if anyone can help me sort out the problem, I'd be very very very glad ...

CSV File

Any help is EXTREMELY welcome !

Thanx in advance

//edit : don't know anything about interpreting Freescan data, but I noticed some weird "Spark" readings ; strange, they're brand new (old ones were not black)

Spark changes often upon load and boost/detonation. Are your cooling fans working? Your file is not long but after a short period your water temps are above 90C. Are you sure you aren't getting too hot and the ECU is going into limp home mode? I didn't see any discenable knock counts so that's good, but you also aren't really getting any boost, map reading remains fairly constant. WEre you driving as normal? Really need a long file with lots of different driving to assess the values properly and read what's happening over a period of time.

Artie


89 White Esprit SE

...a few little upgrades....

93 RX7.....Silverstone

....slightly modded...Muahaha...

New Addition:

1990 300ZX TT......Hmmm

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Hi,

I had a quick look at your file.

In line 27 the problem starts (actually it already starts in line 3). Do you see the very odd (actually WRONG) rpm readings ! Along with this you get irrational load and spark figures.

IMHO its an electronic problem, maybe:

- flywheel sensor

or

- ECU itself

or maybe

- some gizmo with wiring or earth connection

You see, Freescan is a must ;o)

Cheers

Marcus

Did some testing again to sort out the problem(s).

First, changed the spark plugs, went for a 25 km test ride : car drove PERFECT : temps ok, boost ok, no problems at all !

Came back after couple of hours, problems started again :)

Good news : got my Frreescan-stuff today, so hooked up to the car, did a little testing (on idle, sometimes a bit of throttle to avoid engine going down)

I've uploaded the Freescan CSV fil, so if anyone can help me sort out the problem, I'd be very very very glad ...

CSV File

Any help is EXTREMELY welcome !

Thanx in advance

//edit : don't know anything about interpreting Freescan data, but I noticed some weird "Spark" readings ; strange, they're brand new (old ones were not black)


Marcus

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Spark changes often upon load and boost/detonation. Are your cooling fans working? Your file is not long but after a short period your water temps are above 90C. Are you sure you aren't getting too hot and the ECU is going into limp home mode? I didn't see any discenable knock counts so that's good, but you also aren't really getting any boost, map reading remains fairly constant. WEre you driving as normal? Really need a long file with lots of different driving to assess the values properly and read what's happening over a period of time.

Artie

Hi Artie,

I've let Freescan run for a short time, engine on idle (needed a little throttle though to prevent engine stalling) : "check engine" light was on instantly

Did not drive around (wheather was way too bad), I'll make a test drive with Freescan running beginning next week.

//edit : fans are working ; my guess goes now to the spark plug wiring ... I'll do a test ride with Freescan asap ...

Edited by bzguy

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Hi Artie,

I've let Freescan run for a short time, engine on idle (needed a little throttle though to prevent engine stalling) : "check engine" light was on instantly

Did not drive around (wheather was way too bad), I'll make a test drive with Freescan running beginning next week.

//edit : fans are working ; my guess goes now to the spark plug wiring ... I'll do a test ride with Freescan asap ...

Is the chip installed properly? No explanation for why the revs go from 1800 to 5900 in one sample!


89 White Esprit SE

...a few little upgrades....

93 RX7.....Silverstone

....slightly modded...Muahaha...

New Addition:

1990 300ZX TT......Hmmm

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Hi,

Please have a look. In line 27 the revs goto 10513 rpm !!!!!

Thats not a normal rpm number for having to rev the engine to prevent it from stalling, right ?

BTW, did you say that the fans are running !? Are the fans running right from the beginning, when you start the engine from cold ???

If your CEL is ON and the fans are running right from the beginning, then your Chip/Mem-Cal is either not properly installed or is just broken !

Cheers

Marcus

Is the chip installed properly? No explanation for why the revs go from 1800 to 5900 in one sample!

Marcus

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If it is any help, I have a spare working ecu to test.

I am in Cologne, so not too far away from you....

But it sounds like the ECU or a tempsensor.

I still believe a defective temp sensor can cause unexplicable critters in the whole system...

I will be able to tell after exchanging mine..... ( spring time )


Olaf S400 project www.esprits4.de

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I have looked at the file and agree with Marcus that there is bad RPM data at 0% TPS.

I would not drive this car until you have sorted this problem. If CEL is lit what are the storred error codes ?

Dermot

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I have looked at the file and agree with Marcus that there is bad RPM data at 0% TPS.

I would not drive this car until you have sorted this problem. If CEL is lit what are the storred error codes ?

Dermot

Check Engine Light was directly on !

I'll have a ride with it asap, I suppose monday or tuesday ... will give more extended data ...

My local dealer thinks about spark wiring, I'll have a longer Freescan check first :lol:

@esprits4de : thanx for your offer, I'll contact you if needed, is indeed not too far away, Cologne :) Nice shopping always there as well :)


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Spark changes often upon load and boost/detonation. Are your cooling fans working? Your file is not long but after a short period your water temps are above 90C. Are you sure you aren't getting too hot and the ECU is going into limp home mode? I didn't see any discenable knock counts so that's good, but you also aren't really getting any boost, map reading remains fairly constant. WEre you driving as normal? Really need a long file with lots of different driving to assess the values properly and read what's happening over a period of time.

Artie

sorry, have been busy for a while, no time to further check, but today I wanted to have another check (ie a long ride, to build up a long Freescan log) ...

Noticed that the coolant warning light was on, so filled up the charge cooler coolant tank, but when I looked underneath the car, saw ther's a leak ... coolant dripping @ the right hand side of the car, close to the cockpit (so not at all @ the filling point !)

So something has come loose, or ther's a real leak in the tubing ... It's the coolant from the charge cooler that's dripping, not that from the engine itself (that level is fine and remains fine)

I'll have a more intensive look tomorrow, was too dark to check properly in the engine compartment.

Edited by bzguy

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Hans,

We really don't need a longer log file at this point. Since the ECU is producing/responding to bad data at idle it will carry on doing it on the road. Sort out the origin of your check engine light and why the idle RPM data stream is over the place. If the ECU gets bad load data it will apply the wrong spark timing who knows what could happen.

Dermot

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Hans,

We really don't need a longer log file at this point. Since the ECU is producing/responding to bad data at idle it will carry on doing it on the road. Sort out the origin of your check engine light and why the idle RPM data stream is over the place. If the ECU gets bad load data it will apply the wrong spark timing who knows what could happen.

Dermot

Thanx Dermot

Today I've checked it all out : disconnected/reconnected the ECU, checked chip fittings, checked all cabling etc ...

I've replaced the leaking tubing between the charge cooler & the charge cooler coolant reservoir : no dripping anymore, temps are fine and remain fine, did another Freescan check on idle (let the engine warm up a bit and then started Freescan) ; weather too bad to do a test run ...

New Freescan run on idle

Idle seems to be much better now, no stalling, no CEL on ....

I'm a happy man for now :D

Had a quick look on the Freescan data : seems to be quite coherent now, no ?

Thanx all for your advice !


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Thanx Dermot

Today I've checked it all out : disconnected/reconnected the ECU, checked chip fittings, checked all cabling etc ...

I've replaced the leaking tubing between the charge cooler & the charge cooler coolant reservoir : no dripping anymore, temps are fine and remain fine, did another Freescan check on idle (let the engine warm up a bit and then started Freescan) ; weather too bad to do a test run ...

New Freescan run on idle

Idle seems to be much better now, no stalling, no CEL on ....

I'm a happy man for now :D

Had a quick look on the Freescan data : seems to be quite coherent now, no ?

Thanx all for your advice !

You still aren't getting over 78.5 deg C.

82deg C is the minimum running temperature (once warmed up) and anything under will cause the ECU to limit boost.

Put in a new thermostat, a proper 82C on, it's very cheap.

Also your IAC counts are too high for a warmed up ideling Esprit. Should be between 20-40 IIRC.

The high IAC counts could account for some cold engine stalling.

Your MAT is very low 9deg C?

My observations.


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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You still aren't getting over 78.5 deg C.

82deg C is the minimum running temperature (once warmed up) and anything under will cause the ECU to limit boost.

Put in a new thermostat, a proper 82C on, it's very cheap.

Also your IAC counts are too high for a warmed up ideling Esprit. Should be between 20-40 IIRC.

The high IAC counts could account for some cold engine stalling.

Your MAT is very low 9deg C?

My observations.

Thx Travis , some questions though ...

- what's IAC ? Idele Air Control ? Any reason why it reads so high ?

- can it be that MAT is very low because it's freezing overhere ? (Belgium)

- where's that thermostat situated ?

Thanx, greetz

Edited by bzguy

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Thx Travis , some questions though ...

- what's IAC ? Idele Air Control ? Any reason why it reads so high ?

- can it be that MAT is very low because it's freezing overhere ? (Belgium)

- where's that thermostat situated ?

Thanx, greetz

IAC is yes-Idle Air control, it's high because it's probably forgotten where it is, it needs to be reset

MAT is low because it's cold out, yes!

Thermostat is situated beneath the thermostat housing beside the inlet cam pulley. Pic below.

Artie

thermostatoq0.jpg


89 White Esprit SE

...a few little upgrades....

93 RX7.....Silverstone

....slightly modded...Muahaha...

New Addition:

1990 300ZX TT......Hmmm

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Hi Travis,

JFYI the boost control threshold temp minimum is exactly 75

Edited by Paula&Marcus

Marcus

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Hi Travis,

JFYI the boost control threshold temp minimum is exactly 75

Edited by bzguy

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Hey Marcus,

Ok, I see what you mean, it's right there in the manual. 75C.

In my experience I had a thermostat the wouldn't let my car get above 79C, the engine would cut boost and buck pretty badly. I replace the old 82C thermostat with a new 82C thermostat, and the Engine ran just above 82C. It was just an old wornout thermostat. The car quit bucking and cutting boost.

Normally you shouldn't see an engine with an 82C thermostat running at 78C when fully warm... IMO Since the Thermostat is inexpensive ~$4, I would replace it, personally.

Went for a test drive yeterday, same problems again ... starts very fine, but when everything's warm, stuttering starts (I have a Freescan log, I'll upload it).

Seems to be the same problem as Travis had, so I'll replace the thermostat by a 82


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I've been watching this thread with some interest because I seem to be experiencing exactly the same symptoms.

Whilst it normally idles at happily at 1000rpm, sometimes it'll idle at up to 1500 (when warm), but more often, it'll cut out on approach to a junction, usually while I'm trying to coax it into 1st (not always easy with my worn selector). Sometimes it'll "hunt" going from 500 to 1500rpm before settling down. Also, if I try to accelerate from below about 2000rpm, the engine stutters, there's no acceleration at all (not even limp-home level), then suddenly it'll pick up. Sometimes I need to dip the clutch slightly to help it out.

I've only just got FreeScan, and unfortunately the ALDL cable appears to have the pins in upside down, but if I can get that sorted, we may be able to spot some common ground in the logs and get this cracked.

Looking into the ALDL connector (on the cable, not the car) at the pins, with the clip on top, my ALDL cable has the two pins on the top right (green/yellow on the inside), and the single pin (blue) bottom left. Could you confirm that the double pins should be bottom left and the single pin top right?

Phil


More speed, less haste

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I've been watching this thread with some interest because I seem to be experiencing exactly the same symptoms.

Whilst it normally idles at happily at 1000rpm, sometimes it'll idle at up to 1500 (when warm), but more often, it'll cut out on approach to a junction, usually while I'm trying to coax it into 1st (not always easy with my worn selector). Sometimes it'll "hunt" going from 500 to 1500rpm before settling down. Also, if I try to accelerate from below about 2000rpm, the engine stutters, there's no acceleration at all (not even limp-home level), then suddenly it'll pick up. Sometimes I need to dip the clutch slightly to help it out.

I've only just got FreeScan, and unfortunately the ALDL cable appears to have the pins in upside down, but if I can get that sorted, we may be able to spot some common ground in the logs and get this cracked.

Looking into the ALDL connector (on the cable, not the car) at the pins, with the clip on top, my ALDL cable has the two pins on the top right (green/yellow on the inside), and the single pin (blue) bottom left. Could you confirm that the double pins should be bottom left and the single pin top right?

Phil

I'll check that out Phil, got a picture of that somewhere ...


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SALVATION AT LAST !!!!

Had an appointment tomorrow to bring my car to the garage (lack of dry workspace in my garage, way too tight to work on the car), but before doing that, I spent my day on having another desperate look onto the problem, with SUCCCES ! :P

Double checked all wiring etc, checked on the ecu, which was looking fine, at least I thought ....

Putting back the ecu gave me an instant CEL, Freescan gave no data at all, so removed the ecu again and checked on the memcal module in the ecu ...

Another option was cancelling my garage appointment and asking Olaf Krone (thanx Olaf for the offer of the spare ECU !) to test with his spare ecu ...

Guess what ... a tiny pin of the ecu module (the esc part, that small piece covered with gel) was cracked, seemed to make contact and then not, as I can imagine those bumpy Belgian roads : no contact = CEL on, otherwise no roblem ...

In fact, when installing my #3 chip, I had to lift the esc part a bit to be able to install the new chip ; by that, that small pin leg must have cracked ... in fact, very hard to see !!!

So, "reinforced" the pin's leg by soldering with a smd soldeirng iron, put it all back together and went for a rtest ride ; idle was a bit high, so set it to 1200 rpm with Freescan ; and yes, NO PROBLEMS at all !

finally solved ! Maybe ErnieHillard can check his car as well, seems he has the same problem, and as it is is very hard to see ... might be wort the effort I guess ...

I'd like to thank all of you for the big amount of info I got from you all, you can imagine I' very very glad to have my beauty back on the road again ; I was almost becoming desperate :S So thursday I'll take my girlfriend out for a good dinner, off course with the Lotus :o

THANX !


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