Misfire

Ive got a rather annoying missfire that shows at about 4000rpm when the turbo is really beginning to spin. Ive had it for a while but its just got slightly worse. This morning when the turbo got going it took a fit and was going so badly it was quicker to back off. This afternoon it was back to its normal hesitation at 4000rpm. Its got new leads and plugs. Its going in for a proper diagnostic before Donnington but is there any common GTA problem that I may not have thought of that might solve it before then?

I had a similar problem with my Saab 9000 Aero. After replacing all the usual suspects a Saab specialist advised me to put some redex in every orifice.

To my surprise it actually worked, (a bit like the household cleaning agent Clit Bang!!)

It flattened out the misfire the more I drove it, the problem then vanished after about 30 miles. Must have been a spider in the ignition lead.

If only Redex would fix my blown headgasket....

Is it the point in the rev range where the turbo is holding boost (not climbing up to it?) If so it sounds fuel pump or regulator related, so that its having trouble holding a steady fuel pressure.

Also, has it done it since you fitted the plugs, which ones did you use?

Not exactly the same but since I upped the boost on mine it hesitates slightly at 4k, in third mostly ,no misfire but a slight lack of power ,was thinking it was fuel related .The cars running a bit hotter cos of the extra boost as well

[simontaylor]

I had a mis fire a while ago, and so one evening I decided to have a look at it.

Well it was obvious which cyclinder it was, due to the flashing from one of the plug tops, it turned out to be a cracked plug on the ceramic part.

If I were you, when you get back from the pub tonight, just a have a quick look at it in the dark, you may see something???

Its had new leads and plugs......certainly none of them are as bad that they would show a spark! The fuel thing sounds about right....there ia a faint smell nect to the fuel filter.....which hasnt been changed for god knows how long. Couldnt get it undone when I last tried....perhaps its time to try harder!!!! I cant remember which plugs I used..why?

Its had new leads and plugs......certainly none of them are as bad that they would show a spark! The fuel thing sounds about right....there ia a faint smell nect to the fuel filter.....which hasnt been changed for god knows how long. Couldnt get it undone when I last tried....perhaps its time to try harder!!!! I cant remember which plugs I used..why?

The plugs you have may not be suitable. Wrong heat range, especially as you are running alot more power. NGK's are tried and tested and the best to use.

They were Champions....the correct ones for the car.

Mr Jon....where did you put Redex other than in the fuel tank??

[Alpineandy]

Mr Jon....where did you put Redex other than in the fuel tank??

Usually dribble a bit down the throats of the carbs (one hand on throttle linkage to stop it stalling - lots of revs) and in the tank.

Or maybe Mr Jon does it a different way

I had misfiring and poor starting problems with recommended champion spark plugs. I think it was to do with the gap as there was a discrepancy between the manufacturer's gap spec and the renault gap spec and also something to do with resistors. I set them to the lower gap setting and they were OK for a while but I ended up chucking them for some NGKs.

See this for the full gory details:
http://www.renaultalpine.co.uk/PHPBB/phpBB2/viewtopic.php?t=137&start=0&postdays=0&postorder=asc&highlight=spark+plug

I may change my plugs anyway but I didnt get the resistor plugs as you had....I did check carefully that they were the right ones for the car. I have (over)filled the tank with Redex and it may just have been the fact I was coming off night shift, but I think it has cured it
Andy, I spent most of yesterday looking for the intakes on the carbs but without luck......are they hidden behind the turbo???

Fuel filter changed today.....the date stamped on it was 13/08/.....wait for it.....95!!!!!!!!!!!!!!!!!!!! Its 10 years old.....and almost totally clogged. The car is running noticably better now.

[Alpineandy]

Fuel filter changed today.....the date stamped on it was 13/08/.....wait for it.....95!!!!!!!!!!!!!!!!!!!! Its 10 years old.....and almost totally clogged. The car is running noticably better now.

A very common situation