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Ticking over like a bag o' spanners - Fixed

So, 24 hours after the car running sweet as a nut on several occasions, it's now gone back to this!

At least now I know it is definitely ECU related and not an air leak or dodgy coil pack. At a guess, I'd say after the ECU reset, it's trying to retune itself and doing it wrong????? :? :? :?

In the video I'm just firing it up, no throttle or anything - all the cars doing.

 
****UPDATE****

So last Wednesday I treated the old motor to a set of Bosch coil packs (knowing that it could quite possibly be the reason for the rough idle) as it was getting due looking at the state of them and no history in the receipts of them being done.

Once done, give the ECU a reset so that everything was fresh with a clean sheet.

Car carried on as normal with a poor tickover.
Going on holiday next Tuesday in it to the South of France so want it running right.

Anyhow, had it in with my mechanic tonight, taking with me all the DME specs at tickover so we can compare with what the car's actually reading and hopefully identify where the issue is.
Get down there and car is running sweet as. All the readings are fine and now I can't getting running bad!!!

:frustrated: :frustrated: :frustrated: :frustrated: :frustrated: :frustrated: :frustrated: :frustrated:
 
Quick update and hopefully some help.

Last night spent a good couple of hours with the live data being read as it was running poo.

Looks like bank 1 is running leaner than bank 2 (as the o2 sensor readings were consistently showing lower voltage on 1 than 2) and also the STFT - short term fuel trim percentage was in minus figures on bank 1 and positive on 2???????????

Any ideas guys on what's wrong?

:dont know: :? :nooo: :-|
 
apologise if this has already been mentioned, but have you changed your knock sensor?
 
No. Isn't there 2 of them on mine? (M96.04 engine)

I was asking my mechanic last night if this could be the culprit.
 
I would put quite a bit of money on it being the knock sensor mate. im unsure whether you have two or not.
 
Hi Alex

Sounds like this is giving some grief.
Have you now ruled out that this is an ECU intermittent fault?

Since you mention there's a difference in the richness between banks I would be inclined to suspect an O2 sensor problem. I'm not sure which of the pre or post cat sensors control mixture but would certainly be tempted to try swap the sensors over side for side and see if the lean issue presents itself on the opposite bank.

I did have a ticking over issue on mine after I had the engine in bits and that turned out to be O2 sensors plugged into the wrong sockets on the loom. They are located next to the back of the airbox (4 plugs in total).

I'm assuming you don't have any logged faults (interestingly I didn't get any when I had them plugged incorrectly either)..


:thumb:
 
Cheers Chris, read something similar this morning. Will have a good read of this too.

Just gonna have some lunch then get it up on ramps and have a look round the sensors as well as reading live data again. Was thinking of swapping o2 sensors but a bit scared of breaking them whilst trying to undo them. Do they come out easy enough?

Haven't ruled out the DME being faulty yet (ECU)

My mechanic is convinced I've got an injector problem.

Seems worse at times than others though so looks like an intermittent faulty sensor reading to me.
 
The O2 sensors will be a pain in the ass to remove and you may need oxy and cold water to get them out.


The plug the wires and looms maybe be long enough to allow over crossing the left & right sides in the engine bay and so you will fool the ECU with readings off the opposite bank if you have the piwis or durametric for live data
 
Harv said:
The plug the wires and looms maybe be long enough to allow over crossing the left & right sides in the engine bay

:nooo: they're not.
 
Does it only run badly on tickover? Is it rough on WOT too? It will likely be running closed loop on tickover, so using the O2s, but generally won't use the O2s on WOT so might help with diagnosis.
 
only on tickover
 
on idle, give it a tiny amount of gas and let it drop, does it almost stall or stall completely?
 

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