Hesitation when accelerating/decelerating
Discussion
I have a 91 S3 and when accelerating/decelerating the car seems to hesitate and slightly lurch. It also does not like sitting at 40mph at starts lurching agian. I am running it on 2 tanks unleaded and 1 leaded as advised by Peninsular. This isn't pinking is it or possibly the timing out? Anyone got any ideas?
A Very depressed Hopper (litterally)
A Very depressed Hopper (litterally)
quote:Why do they advise that? Just have the timing set up for unleaded at a ford garage (*) and use unleaded. I do that and it runs perfectly.
I have a 91 S3 and when accelerating/decelerating the car seems to hesitate and slightly lurch. It also does not like sitting at 40mph at starts lurching agian. I am running it on 2 tanks unleaded and 1 leaded as advised by Peninsular.
Regards,
Mark
(*) note it must be somewhere where they can hook up some diagnostic machine to one of the ports in the spagetti wiring above the passenger footwell to set it in timing mode (or something like that), simply pointing a timing light at it without doing this will not do the job. This cost me about 30 quid at a ford garage a couple of weeks ago.
Interesting, 
I have just developed the same problem in my S3. General running is fine, but after a while when i lift off the accelerator the engine seems to die rather than just decelerate. Also happens occasionally when I hit a bump, engine seems to cut and then fire up again. What is really annoying is that it doesn't happen all of the time. Out in the lakes with the Cumbria lot on Sunday and hardly noticed it. Coming back from work yesterday, bl**dy awful 
.
I have been running unleaded fairly exclusively for about 18 months with no problems and I have the correct ECU, as per the bible.
Any ideas greatly appreciated before I ask HHC to look at it and charge me lots of money.
Bugs
I have just developed the same problem in my S3. General running is fine, but after a while when i lift off the accelerator the engine seems to die rather than just decelerate. Also happens occasionally when I hit a bump, engine seems to cut and then fire up again. What is really annoying is that it doesn't happen all of the time. Out in the lakes with the Cumbria lot on Sunday and hardly noticed it. Coming back from work yesterday, bl**dy awful . I have been running unleaded fairly exclusively for about 18 months with no problems and I have the correct ECU, as per the bible.
Any ideas greatly appreciated before I ask HHC to look at it and charge me lots of money.
Bugs
Same old problem again eh!
Drives you round the bend this one. Now, there are several reasons why this will happen. the main one is the throttle pot (again) why? well the stupid thing seems to be affected by all sorts of things. apparently the weather can have an effect on it. If it was damp, small drops of water can get into it and several threads from the past have said that it should be sealed up as much as possilbe. This may account for your engine playing up on different days. However they are not cheap. It is possible to fit a pot from a more modern TVR which is better sealed and less likely to play up.
If you can get the dosh, have it checked before getting your wedge out!
good luck.
let us know what it was please.
gadgit.
Drives you round the bend this one. Now, there are several reasons why this will happen. the main one is the throttle pot (again) why? well the stupid thing seems to be affected by all sorts of things. apparently the weather can have an effect on it. If it was damp, small drops of water can get into it and several threads from the past have said that it should be sealed up as much as possilbe. This may account for your engine playing up on different days. However they are not cheap. It is possible to fit a pot from a more modern TVR which is better sealed and less likely to play up.
If you can get the dosh, have it checked before getting your wedge out!
good luck.
let us know what it was please.
gadgit.
quote:
Same old problem again eh!
Drives you round the bend this one. Now, there are several reasons why this will happen. the main one is the throttle pot (again) why? well the stupid thing seems to be affected by all sorts of things. apparently the weather can have an effect on it. If it was damp, small drops of water can get into it and several threads from the past have said that it should be sealed up as much as possilbe. This may account for your engine playing up on different days. However they are not cheap. It is possible to fit a pot from a more modern TVR which is better sealed and less likely to play up.
----------------------------------------------------
The problem has only been over the last week or so and I haven't seen sight nor sound of rain, or washed the car for that matter. Will check the thottle pot anyway.
quote:Mine hesitated under hard acceleration and it was 2 degrees retarded compared to what it should be.
Could it be timings, what are the symptoms if it is this?
quote:Engine ignition timing to far advanced. You'll here the engine making a kind of pinging noise under hard acceleration that isn't there normally.
What is pinking?
Mark
quote:
(*) note it must be somewhere where they can hook up some diagnostic machine to one of the ports in the spagetti wiring above the passenger footwell to set it in timing mode (or something like that), simply pointing a timing light at it without doing this will not do the job. This cost me about 30 quid at a ford garage a couple of weeks ago.
No need. Just move the plug or check the ECU number. DEtails in the bible and in the unleaded FAQ on my website. You had to reset the timing which is why you had a trip to Henry Land.
Steve
www.tvrbooks.co.uk
Hopper,
I've had this problem and the cause was two seperate things, both cheapies I'm glad to say.
The first one was a hole in the HT lead that goes to the ignition coil. The hole was letting air in, where there should be a vacuum. The hole had occured due to years of my bonnet lying on top of it. Perhaps you have the same problem?
Unfortunately, this only improved matters for one outing. The connections to the vane air flow meter were the wrong way around. I think this must have happened when the engineer was trying to locate the source of my original fault. My symptoms were exactly the same except there was loud back firing (I don't just mean the usual popping and banging) these were explosions! Also the EMU was trying to over compensate by flooding fuel into the engine, causing fuel to spray out of the exhaust and for the car to lurch all over the place. Idling was very uncomfortable.
Hope you get it fixed.
>> Edited by Heath on Sunday 13th October 11:19
I've had this problem and the cause was two seperate things, both cheapies I'm glad to say.
The first one was a hole in the HT lead that goes to the ignition coil. The hole was letting air in, where there should be a vacuum. The hole had occured due to years of my bonnet lying on top of it. Perhaps you have the same problem?
Unfortunately, this only improved matters for one outing. The connections to the vane air flow meter were the wrong way around. I think this must have happened when the engineer was trying to locate the source of my original fault. My symptoms were exactly the same except there was loud back firing (I don't just mean the usual popping and banging) these were explosions! Also the EMU was trying to over compensate by flooding fuel into the engine, causing fuel to spray out of the exhaust and for the car to lurch all over the place. Idling was very uncomfortable.
Hope you get it fixed.
>> Edited by Heath on Sunday 13th October 11:19
I am running it on 2 tanks unleaded and 1 leaded as advised by Peninsular. This isn't pinking is it or possibly the timing out?
Why? By 91 all 2.9 engines were designed to run on unleaded with the corect timing. In fact I believe all 2.9 were capable of running on unleaded, it was only some for the S1 2.8's that couldn't run on unleaded.
Mark
Sorted, took the car to turbo Technics in Ringwood. They took it for a run and suggested the injectors needed cleaning as it had been sitting for a while and apparantly they get clogged up. They are suppose to give a fine spray, but they can get clogged and deliver droplets instead, hence the delays and bad constant speed running. 90 quid and it is back to normal and also the trottle wasn't opening properly, so they dealt with that as well. They also had some other suggestions, which I wanted to put past you lot.
Lift the throttle peddal up and lengthen the throttle arm back to how Ford originally set it up. TVR have drilled a hole closer to the end. Apparantly the injectors are set up to give a certain amount of fuel depending on how quickly the throttle is opened, Tvr has adjusted the throttle arm, but have they adjusted the rest of the set up?
I am not too technically minded (as I crunch numbers for a living), so the above may not be totally correct and any comments are welcome.
Anyway, back to the subject, drove the car back to London in the rain last night and it ran beautifully. The hesitation had all but gone, and she wasn't tripping up when at steady speeds. Absolutely Ideal!!!
Also why do I run it on a mixture of petrol? I've got the ECU for a leaded engine and I can't find any paper work to say it has been adjusted. Spoke to Peninsular and they said it would be fine to run on either, but would be best to run it on a 2:1 format. If it started pinking then to put it back on leaded. Turbo Technics agreed and said it definitely wasn't pinking.
Have rambled for ages now, but am so much happier. Big thanks to The Turbo Technics guys
Happy Hopper with a beautifully running S3.
Lift the throttle peddal up and lengthen the throttle arm back to how Ford originally set it up. TVR have drilled a hole closer to the end. Apparantly the injectors are set up to give a certain amount of fuel depending on how quickly the throttle is opened, Tvr has adjusted the throttle arm, but have they adjusted the rest of the set up?
I am not too technically minded (as I crunch numbers for a living), so the above may not be totally correct and any comments are welcome.
Anyway, back to the subject, drove the car back to London in the rain last night and it ran beautifully. The hesitation had all but gone, and she wasn't tripping up when at steady speeds. Absolutely Ideal!!!
Also why do I run it on a mixture of petrol? I've got the ECU for a leaded engine and I can't find any paper work to say it has been adjusted. Spoke to Peninsular and they said it would be fine to run on either, but would be best to run it on a 2:1 format. If it started pinking then to put it back on leaded. Turbo Technics agreed and said it definitely wasn't pinking.
Have rambled for ages now, but am so much happier. Big thanks to The Turbo Technics guys
Happy Hopper with a beautifully running S3.
Lift the throttle peddal up and lengthen the throttle arm back to how Ford originally set it up. TVR have drilled a hole closer to the end. Apparantly the injectors are set up to give a certain amount of fuel depending on how quickly the throttle is opened, Tvr has adjusted the throttle arm, but have they adjusted the rest of the set up?
This sounds like nonesense. The ECU measures the throttle position in terms of the angle of the spindle in the throttle body; it doesn't care how far you have to push the pedal to achieve that.
Lots of questions to PH'rs out there.
Can the injectors be cleaned by the average home mechanic? Do you have to strip all the plenum off to do it or can one simply rely on the petrol additive route? How do you clean the injectors?
Do injector nozzles wear out? Should the injectors themselves be replaced from time to time? If so how often?
Can the injectors be cleaned by the average home mechanic? Do you have to strip all the plenum off to do it or can one simply rely on the petrol additive route? How do you clean the injectors?
Do injector nozzles wear out? Should the injectors themselves be replaced from time to time? If so how often?
PeterC said: Lots of questions to PH'rs out there.
Can the injectors be cleaned by the average home mechanic? Do you have to strip all the plenum off to do it or can one simply rely on the petrol additive route? How do you clean the injectors?
Do injector nozzles wear out? Should the injectors themselves be replaced from time to time? If so how often?
No they need a special machine which will usually test them for flow rate and spray pattern. They can wear out/fail. The additive is a waste of time IMHO. Take them to an injector cleaner. About £15 a time. Be aware as stated int' bible very easy to break them when removing them on a V6.
Steve
www.tvrbooks.co.uk
Steve
Many thanks for that. At what point would you suggest that injectors ought to be replaced? I have an S3 thats done around 45,000 and do get some erratic running at times.
For instance I have to drive at 30 mph in 3rd and 40mph in 4th. Driving at low speed in any higher gear results in violent shunting through transmission.
Many thanks for that. At what point would you suggest that injectors ought to be replaced? I have an S3 thats done around 45,000 and do get some erratic running at times.
For instance I have to drive at 30 mph in 3rd and 40mph in 4th. Driving at low speed in any higher gear results in violent shunting through transmission.
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