Still got a bit of a stutter on acceleration HELP!

[haddock_n_chips]

Hey all

had a problem for a while now with the car stuttering on acceleration

car is 1991 scala injection, DX engine

change plugs, leads, dizzy cap, rotor arm, fuel neck, fished out all rust from tank, cleaned the injectors utrasonically

running out of ideas! any help? PLEASE!!!

its only when you pull away but in all gears, so mainly for the first 2000 revs then its fine and pulls really well

Cheers guys

WiLL.......

[haddock_n_chips]

just thought this should really be in technical help

mods can you move it please? ta very muchly :)

[haddock_n_chips]

anyone?!

[big nick]

sticky throttle cable? sticky butterfly? duff engine mounts?...

[haddock_n_chips]

throttle cable new

whats a butterfly?

mounts ok

[christhemann]

Sounds familiar!

My old injection Scala did that for a while.
One thing that really improved it was changing the main fuel pump, and also the small "lifter" pump inside the tank.
Both need to be in good shape, if they're noisy might be an indication!

The butterfly is inside the throttle body, which is what connects to the inlet manifold and is pulled by the throttle cable.
Worth spraying some carb cleaner into this and cleaning up well inside, after taking intake pipe off.
Also the air flow meter (i think it's called), which is inside the air filter housing, this can apparently stick and needs to be clean and free.

Also, did you get the mixture checked? Might be worth a shot, although not quite as crucial as with a carb engine.
Last thing, check there are no air leaks. You can usually hear them hissing, mine split the small rubber pipe to the inlet manifold in the centre of the engine.

Sure theres some other things...

[MikeH]

Sounds like a timing issue to me - retarded ignition timing tends to make the car a bit flat at lower revs.

If the base setting is correct, it could be the vac advance is iffy. Have you checked that the dizzy vac pipe is not leaking or blocked, and that the dizzy advances the timing as you start to open the throttle? At wider throttle openings and higher RPM, the open throttle allows the vacuum to be filled, so the vac advance isn't operating - then the centrifugal advance takes over.

Dirt in the throttle body could also block the inside of the TB where the vac pipe connects. Can you feel any suction down the vac pipe with the engine running, and at light throttle openings?

[haddock_n_chips]

ooh eck i havent got a clue with timing

air flow sensor plate and everthing is centred and clean, airfilter is clean too

anyone nearby anygood with timing wanna help? or reccomend a good garage but im skint so cant reallty afford that

[Nate]

just loosen the pinch bolt on it, then turn it (clockwise? i'm sure someone will confirm) to advance the timing slightly. keep doing that until the engine pinks when you give it a bootfull, then back it off slightly. much easier han using a timing light, and usually gets you a more driveable motor

[big nick]

clockwise or anti-clockwise to advance? I got a Kjet dizzy here with a much nicer advance curve than my carb dizzy and I'm gonna have a look at fitting it and playing with it over the weekend, but I wanna know which way is which before I try to tune it by ear!

[MikeH]

Anti clockwise to advance on an 8 valve. If you're going to try and time it by ear, mark the position you started at, so you can go back to it if needed.

[scirocogtx]

Did you change the ignition coil?
Check crimp connections leading to it?

[haddock_n_chips]

changed coil so no probs there

just put new injectors in (all 4) and seems ok now so far :)