recently my S has been ‘stuttering’ … I’ll be driving along quite merrily when all of a sudden the revs will drop sharply for about a second, the car will have no power, then suddenly blip back to life.
if the revs are low enough to start with, this can result in a stall.
anyhow this came to a head on Saturday when the stall happened ‘mid roll’ into a roundabout, and i nearly got taken out by an articulated lorry!
B&C will be looking into it in the coming weeks, but given it has been happening for a while, and their best solution so far has been to reflash the ECU (didnt work) I’m getting a little impatient/concerned
when it happens at motorway speed the car lunges forward as the power cuts out, and i am literally thrown forward (if i didnt have a belt on it could so some serious damage)
summary of when problem (VERY intermittent) has occurred:
heavy acceleration (at all speeds, all gears)
motorway cruising speed
slow trundle speed (20mph, resulting in stall)
slowing to a stop at a junction (resulting in stall)
mid rolling into a roundabout
i thought it might be correlated to me using the a/c - but haven’t been able to confirm or rule that out, yet
the car doesnt actually stall in the proper sense… the ignition lights dont come on, and it doesnt feel like a bump start when the power returns
the drop off in power is not the same as if i lift off fully, its more dramatic than that (almost as if the clutch has been depressed) - this makes me think throttle position sensor is not at fault
any thoughts? has anyone experienced something similar?
Besides the “old” issue(started with some '06 cars – there is a TSB on this from Lotus) that an AC module was causing electronic interference resulting in the ECU to reset/cut out, I’d also recommend having the shop check the car’s primary ground. Insufficient earthing could cause this type of problem.
anyone experience momentary engine cut out on an Exige S?
It is like someone turns the “switch” off for a second then turns it on. both light throttle and heavy load.
The response:
Posted: Sun Sep 09, 2007 8:18 am Post subject:
Thomas Praetzel wrote:
Loose ECU connection? Get it back to the dealer and buy yourself a good quality OBD2 scanner for future use. You should be throwing a code somewhere. My RSX was giving me [censored], took it into the dealer, they hooked up the scanner, printed out the report, and charged me a little over 100 bucks! Never did any mechanical work because the car is modified. Nice work if you can get it, took them about 10 minutes.
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I’m going to second the loose ECU wire/connection. My S was doing this and then it became so bad that it would shut off for 5, 10, 40, 60, 90, you name it minutes without the ability to restart. I checked the ECU connections and didn’t find anything. The DEALER found wires that weren’t seated correctly within the harness connection - 2 of them. Apparently, as things heated up and became more flexible, the wires could back out of the plug just a touch, confusing the hell out of the ECU or losing connectivity altogether.
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Check your car’s primary ground. Sometimes what appears to be fuel starvation may not be fuel starvation. If the “earthing” points are not secure/adequate (especially from ECU plate to chassis earth stud), the engine can cut out/misfire momentarily. It appears to be fuel related because it doesn’t seem to happen when the gas tank is full (or immediately after you fill it)… but that’s because the ECU is using the ground for the fuel sender since it’s primary ground is inadequate. The problem is…as the fuel level drops, resistance in the ground for the sender is created and the fuel sender ground becomes insufficient for the ECU to function properly
My ‘S’ has shown similar symptoms on a couple of occasions - most noticeable when cruising on a light throttle - sometimes the engine dies momentarily as if my foot had slipped off the throttle pedal, then bounces back to life. I’ll get mine into Merritts for a check too.
Yes, I have experienced this once or twice before. Initially attributed to the A/C usage as well, as both were being experienced in A/C ON.
But the clarity provided brings me reasonable proof for the dealership to investigate the ECU and ECU wiring harness and points should it be experienced again.
It isn’t a unique situation. I’m on an FY07 Exige S.
I had this problem, well I say that my girlfreind was driving at the time. Car sputtered, died and came to a stop twice, once whilst accelerating and the other just cruising at 50. B&C changed the Throttle position sensor and the sender at the accelerator. However after this happened the second time they changed the entire throttle body and Lotus provided B&C with some new software for it. Has been fine so far…
having driven around without air-con for about a month, and not experiencing the problem once, only to turn the air-con on and experience it pretty much straight away… the conclusion for me is pretty clear. Will have it checked out at the 10k service in a few weeks.
N.B.
air-con is the thing that cools the air blowing into the cabin, in case any S1 owners have stumbled into the wrong forum
P.S
Saw a really nice blue S1 in Guildford (i think??) earlier
so it appears this was caused by a dicky “fan control module”. When you turn the air con on (cold) there are two fans that fire up and this is controlled by a module (this is my understanding from what B&C told me). So that module has now been swapped out under warranty… lets see if the problem goes away. Apparently it has affected more than a few S2 S’s.
My S2�S has done this once about two weeks ago. The car was about 5 mins into the journey home, so temp quite cold. Air con off. Going up a hill I court up with some traffic, dipped the clutch to change down into 3rd gear and it cut out. I just put this down to the comparatively small engine permanently driving the supercharger, sometimes its bound to fluff. Normally small engine SC cars disengage there SC at low revs on a clutch a bit like an air-con system. I may have to be less pragmatic about it if it keeps doing it though!
SERVICE BULLETIN Date: 03.08.06 2006/20
Model: '06 Elise/Exige a.c.
TITLE: Momentary engine power interruption.
REASON: It has been found that on a very small number of '06 model year cars, with an unfavourable tolerance
a.c. control module, it is possible under some circumstances that sparking across the a.c.
compressor relay contacts can cause a voltage spike which results in the engine ECU resetting.
This will be experienced as a momentary interruption of engine power, and is likely to occur only
very occasionally. It is also possible that a throttle related trouble code may be set. e.g. P0638.
ACTION: If this symptom should be reported, it is recommended to replace the a.c./fan control module
A117M0038F.
Dont forget that people only talk about their car’s problems so it puts a slant on things. Normally our cars are pretty well behaved and we share this sort of info for the common good. My cars behaved well all year touch wood.(I obviously haven’t bee driving it hard enough).
Take care tommorrow, its amazing how crap an Exige is on the filthy country lanes at the moment. Use your speedo to judge your speed. I’m quite surprised to find that you can find yourself doing quite high speeds without thinking about it. Just imagine what an old hatchback would feel like in same conditions and consider what is fundamentally different from an Exige… 4 cold tyres with bugger all tread and no ESP…