Well, it's because in the quest to cure the 'misfire' that I am experiencing I have had the thing on a citroen elit analyser which showed up absolutely nothing. I've also swapped the coil pack and no difference.
The only thing the analyser said was intermittent O2 fault and intermittent load fault which the guy said was irrelevant.
I think it's going to come down to willy nilly replacement of sensors and hope one of them cures it.[:(]
Why am I asking all these silly questions?
Moderator: RichardW
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- Posts: 1626
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- My Cars: C5 V6 Mk1 assainated by wife
Renault Kangoo 1.6 auto, tarted up and remapped
Still missing the Xantia V6
Not missing the AX - Contact:
Xantia V6 24v. I'm not even sure if it's a misfire in the true sense of the word. The effect is jerky acceleration. When stone cold it runs how you would expect. Then, as it starts to warm the acceleration becomes erratic and you can feel it hesitating. Once you get going and up to cruising speed it seems to run fine at constant throttle.
Also if you have been stuck in traffic for a while and it gets fully hot it seems to run best of all, but after a long stretch of motorway driving, when you slow for a junction or roundabout the hesitation comes back as you accelerat away. Sometimes after braking almost to a stop, when putting your foot down to pull away again it almost dies then the power comes in with a bang.
Also if you have been stuck in traffic for a while and it gets fully hot it seems to run best of all, but after a long stretch of motorway driving, when you slow for a junction or roundabout the hesitation comes back as you accelerat away. Sometimes after braking almost to a stop, when putting your foot down to pull away again it almost dies then the power comes in with a bang.
tough one ...
If an earlier carb engine, i'd say the accelerator pump hesitating, momentarily leaning the engine.
This points to fluctuations in the fuel pressure on injection systems.
Over riching the engine may give similar symptoms, but then you should occasionally have a backfire on the intake.
The ignition vacuum advance mechanism/sensor could (mis-) behave like this too, simply by having any hose connection split or oil contaminated, even a split diaphragm.
An ignition problem would more than likely come in constantly, at a certain engine temp, so this I rule out.
If an earlier carb engine, i'd say the accelerator pump hesitating, momentarily leaning the engine.
This points to fluctuations in the fuel pressure on injection systems.
Over riching the engine may give similar symptoms, but then you should occasionally have a backfire on the intake.
The ignition vacuum advance mechanism/sensor could (mis-) behave like this too, simply by having any hose connection split or oil contaminated, even a split diaphragm.
An ignition problem would more than likely come in constantly, at a certain engine temp, so this I rule out.
Where I used to work we had 6 cavalier GSi's with that sort of problem and a couple of belmont CD's (yuk) These syptoms only emerged after about a year, tried everything dealer software updates the lot all no good.
Out of desperation had them fitted with superchips (about £300 each) that cured them instantly from then on they really were amazing to drive (even the belmonts)this might be worth a try.
Try taking it to a purely Electrics/injection specialist they always seemed 200% better than the dealers
Out of desperation had them fitted with superchips (about £300 each) that cured them instantly from then on they really were amazing to drive (even the belmonts)this might be worth a try.
Try taking it to a purely Electrics/injection specialist they always seemed 200% better than the dealers
When things are a bit too complicated, I always tends to shout commands to operators around any industrial machinery at fault !
As an engineer, you basically <i>have</i> to get your self decent working conditions. It wont help you if you're tracing faults at the can filler machinery, and then operators keeps hitting the emergency stops because of faulty cans at end of the production line ...
meaning : <i>must</i> be a way of cutting off that adaptive gearbox control. Cant be right that an adaptive gearbox ECU would stop engine, if you take out the gearbox ECU fuse, or rip it's multiplug ...
You simply have too many variables right now to get a fair chance !
As an engineer, you basically <i>have</i> to get your self decent working conditions. It wont help you if you're tracing faults at the can filler machinery, and then operators keeps hitting the emergency stops because of faulty cans at end of the production line ...
meaning : <i>must</i> be a way of cutting off that adaptive gearbox control. Cant be right that an adaptive gearbox ECU would stop engine, if you take out the gearbox ECU fuse, or rip it's multiplug ...
You simply have too many variables right now to get a fair chance !
How long can the misfire be sustained? Is it long enough for an exhaust gas analyser to get a reading?
On the powerchip question, there appears to be a tuning chip available from several vendors in Europe e.g
http://users.otenet.gr/~mwise/power-tuning/citroen.html
It is possible that the software map is marginally unstable at some point and gives these symptoms due to engine wear. I know of an example of this on mid 80s 3.6 litre Jaguar engines.
Mike
On the powerchip question, there appears to be a tuning chip available from several vendors in Europe e.g
http://users.otenet.gr/~mwise/power-tuning/citroen.html
It is possible that the software map is marginally unstable at some point and gives these symptoms due to engine wear. I know of an example of this on mid 80s 3.6 litre Jaguar engines.
Mike
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- Posts: 1626
- Joined: 26 Feb 2004, 23:21
- Location: Cloud Cuckooland
- My Cars: C5 V6 Mk1 assainated by wife
Renault Kangoo 1.6 auto, tarted up and remapped
Still missing the Xantia V6
Not missing the AX - Contact:
Well thanks to the stroke of genius by Anders I think I can eliminate any problem with the engine itself,and am now pointing the finger at the gearbox.
I pulled the fuse that supplies the autobox ecu this morning. The box duly locked itself into third gear and although obviously sluggish, there wasn't a hint of hesitation, stutter, misfire or anything, the engine ran smothly through the entire rev range from cold to hot.
So now I have to figure out exactly how much interaction there is between the ecu's and whether the gearbox ecu is telling the engine to retard the ignition or whether the stuttering comes from the hydraulics of the gearbox going into spasms.
I pulled the fuse that supplies the autobox ecu this morning. The box duly locked itself into third gear and although obviously sluggish, there wasn't a hint of hesitation, stutter, misfire or anything, the engine ran smothly through the entire rev range from cold to hot.
So now I have to figure out exactly how much interaction there is between the ecu's and whether the gearbox ecu is telling the engine to retard the ignition or whether the stuttering comes from the hydraulics of the gearbox going into spasms.