Any ideas

[steve1]

Went out for a blast today, (sun was out), drove some lovely 'b' roads, all well, then went onto a dual carriageway, everything appeared to be ok until I accelerated hard whilst in sixth gear from about 90ish, it just felt like something had rear-ended me, an almighty miss-fire or back-fire of some sort, and it just didn't feel comfortable accelerating.
Tried a few times at different speeds and in different gears, but it was only when in sixth and accelerating hard from about 90-100.
Have tried a different grade of fuel, but still the same.
Will get it to the garage on Monday, but it would be nice to have some ideas.
Steve.

[JLSELAN]

That sounds very much like a fuel delivery problem--not enough fuel getting to the cylinders to sustain high engine demands.
Suggest checking fuel filter, pump, injectors, etc.

[snuffy]

I've had a terrible misfire on several occasions but in all gears ( but the same as you, when accelerating ). Has the car been stood in the rain ( it did piss down on Friday night ! ) or have you recently washed it with a hose ? When I've it it was after it had been stood in the rain or washed. It did not happen straight away but after a miles.

[leadboot]

I had something similar - quickly traced to a duff plug.

[joust]

Check your vacuum hoses. If air leaks it can cause this sort of thing. Failing that sounds like a breaking down plug coil.

J

[steve1]

Yes I did wash it, but am very careful with the hose, also i allowed it to stand for quite a while with the rear clam open to dry off, ( but I will check for any water where it shouldn't be ).
The plugs were changed on the service last week, could be a duff one, or indeed a bad gap on one I suppose, ( again, will get it back to them so as they can check this ).
Also, all the pipes were checked, and indeed one was perished, I think it was the fuel return line, so hopefully they would have spotted if any others were knackered, ( as above ).
Does the ECU log any faults, or is it not that type, ( just a thought, as it would be easy to see if anything was breaking down under load ).
Steve.

[GTO400]

Steve,
Sounds like plug gaps, if they are too wide it will misfire on full boost either that or it could be hitting over boost and the Ecu cuts the ignition, you should be able to tell this from the boost guage.
The Ecu doesn't store any faults etc.
Kevin

[RobP]

Steve -sounds like plugs to me. When were they last changed?

[Mike Tuckwood]

It sounds like the spark being blown out to me get the plugs pulled out and close the gaps down slightly on them.

Either that or there is a boost cut being hit? Is it a standard car or has the exhaust or intake been modified in any way? Was it especially cold weather when it happened?


Mike

Edited by Mike Tuckwood on Sunday 2nd March 14:13

[steve1]

The plugs were changed as above, last week, so will definately get them checked by the place that seviced it.
As for the exhaust, it's a Hayward and scott de-cat.
Of out now to do some more testing.
Steve.

[EddieC]

Steve,

May be worth checking that the car was remapped when the exhaust was fitted and also that it has an upgraded fuel pump to deal with the possible extra demand.

Eddie

[steve1]

Car has not been re-mapped, am thinking of getting this done, not so much for power gains, but purely to make sure the car is running at it should be.
Have just re-gapped all the plugs, they were all around 50thou. so re-set to 40thou.
Went out for a test drive, and all appears to be ok. Result.
Thanx for all suggestions.
Steve.

[Jenx]

steve1 said:

Car has not been re-mapped, am thinking of getting this done, not so much for power gains, but purely to make sure the car is running at it should be.
Have just re-gapped all the plugs, they were all around 50thou. so re-set to 40thou.
Went out for a test drive, and all appears to be ok. Result.
Thanx for all suggestions.
Steve.

I have no tie with Rousch, I don't have thier exhaust system...However, I have met, and talked to, Trevor (Yellowshed) who does the mapping there, have talked to almst all the UK owners who have a Rousche system, and have read every thread on PH and our US cousin's "Noble Forums" over the past 4 and 1/2 years. If I could give you, or anyone else, one piece of advise, it would be to take your car to Trevor after any modification and get it rolling road re-mapped. If you value your car, then a couple of hundred quid getting it to run properly is peanuts...and the gains far outwiegh mere money.


Martin.

[steve1]

That's probably what I shall do, just trying to find the time to get to him.
Steve.