S1 JOHN

anybody got any ideas heres whats been changed

2 sets of plugs
2 sets of leads
dizzy cap
rotor arm
dizzy

absolutley stumped i need help

Its missing slightly on idle then as you rev it up it misses till about 2500revs then goes away , when under load its seems to miss even more , but as soon as you come on boost its fine

ideas?????

DazC

iTrader: (1)

John, have you checked the cam lobes, compression, valve springs and that all the square rockers are fitted under the rocker arms? (if the car was running fine before and has just started doing it, forget the last bit)

Rick

I'd check both the cam and ignition timing.

SafeChav

Tiny air leaks can make it sound like its miss-firing, for example, not having your mixture screw blocked on the air box/metering head assembly. The early ones IIRC have a screw in them to block the hole, i experienced this problem on my first RS due to the screw being substituted for a piece of masking tape

S1 JOHN

engine was taken from my mates car running fine when removed now its in this and missing

metering head is blocked off

and it doesnt just sound like its missing it actually is

DazC

iTrader: (1)

Did you swap the metering head and injectors as well John?

S1 JOHN

the metering head we had was tossed so its had another 2nd hand one injectors were not the same ones from the engine

SafeChav

Yeah i know what your saying, mine we tried everything to cure what appeared to be a miss fire but after all the expense and changing parts we found the real fault. extremely difficult to tell the 2 apart though if the air leak is tiny.

What parts of the engine and running gear arent from your mates car then. i would elimate the "foreign" parts first

S1 JOHN

all that came from the other car was a bare engine and turbo

SafeChav

Well.......i know its a real pain in the arse but in such cases you have got to pain stakingly rule out all the posibilities. Quite a few possible ones in this case.

Have you got a vacuum gauge? And have you compression tested the engine since its been in your car?

DazC

iTrader: (1)

Seems a odd one this John. I don't think you are going to trace it so easily.

Are the injectors known to be in good working order?

S1 JOHN

think so