N3WwrxB0Y

Need some more help peeps, car had a jerking problem when driven hard, have just replaced plugs and coil packs on advice and the problem is still there, its not as bad as before but in the higher gears it will jerk quite badley.

Also i dont seem to get any turbo 'kick' just a slow increase in power.

Car is 93 WRX run on optimax

Any help appreciated

nom

Sounds like fueling to me (too lean mixture), which is not a ggod thing!
Any guages measuring stuff?

wanted

I agree with nom as youv'e already changed the obvious. The fuel pumps on the early cars are crap to start with and if it is the fuel pump thats the problem, driving the car will only cause damage.

N3WwrxB0Y

Ok thanks, iv got a lamdalink waiting to be fitted, il do that later and see what that says

Forgot to say as well, iv checked the boost solonoid and the maf sensor and they both looked pretty clean

Mods iv got are hks panel filter and full exhaust system including full decat, other than that standard.

Anything else i can check ?

nom

Not really - once the AFR meter is in, they'll be, I think, confirmation of the weak mixture. Then it's time to track it down!
Could be low fuel pressure, ie the pump on the way out (can't think of any obvious check for that that doesn't need some sort of at least vaguely special kit ), or possibly a squished fuel tube somehow (wouldn't need to be some serious squishing, though!). Faulty MAF - I don't think common on that model (how's your idle?). Confused ECU? (disconnect the battery & see what happens - this is a good way to check for many faults as the ECU can 'learn' its way round failing components - disconnecting the battery overnight makes it forget this stuff so the problem manifests itself big time!).
That's all I can think of for now...

N3WwrxB0Y

thanks again,

idle is fine, car is great through most of the rev range, il go fit the AFR now and post how i get on

N3WwrxB0Y

Fitted the AFR,
it reads red/orange flickering on idle
and the last green led when its being driven (just on boost) and all the way to the redline.
The display is never 'smooth' it is always jumping around, are they all spose to do this?
i would say the readings say im probably a bit rich ie no fuel prob. What do ya reckon ?

nom

Sounds right, yes. Should be jumping about 'on cruise' - well, swinging rather than jumping
Hmm...

N3WwrxB0Y

Forgot to add, did an ecu reset last nite as well, car feels much quicker now, but does still cut out, any other stuff to try ?

nom

Ok, a bit of clarification on the work 'jerk'
Is this good acceleration, then power cuts totally for a second (feels like the brakes have been slammed on), or stuttery?

N3WwrxB0Y

yeah it totaly cuts, quite violently, its ok in first and second but know does in third as well as 4th and 5th.
Fuel cut maybe, over boost ?
anyway to test ?

monkeyboy

Mate I had this on my MY98 over the past couple of weeks.

The car would pull away fine untill i got to about 3500 or 4000 rpm then it would throw me towards the windscreen as though id jumped on the brakes!

I found that the wired plug connecting to the MAF was not clipping on properly and sliding about under hard acceleration. I wedged the plug on with a little help with some superglue!! and all seems to be a bit better though still not 100% so im still playing with it. I will let you know my findings

MB

N3WwrxB0Y

Iv had the airbox/maf off a couple of days ago to change coil packs and plugs, checked it all over then, looked ok 2 me.
Thanks anyways il double check it when i get home

mmm silver

dont know if this is of any assistance have exactly the same problem on N/A sport 1st through 2nd fine hit third to 5th between 3500/4500 and feels like some ****'s just pulled up the handbrake, then all off a sudden will pick up and will rev fine to the red line???? WTF!!! tried new leads/plugs/ total clean of k&n filter.. new coil packs and the stupid thing is it dont do it all the time maybe 1in10 times the car is driven.

ARRGGHHH car was running so well till now!!!

nom

Ah.
Well, it's overboost leading to fuel cut.
Sorry, have no idea what goes on in a N/A car - or rather why it would be affected in the same way!

There is a fix for this, but never having done it myself, I'm not too sure what it is... Something to do with the boost solenoid getting oil in it. Tubes need to be unplugged, carb/brake cleaner (or similar) squirted in, all plugged back together again & there you are Or, at least, if it's still doing it, it's time to move on to something else...
Ha-ha, pinching someone else's words :
Hope that helps!

N3WwrxB0Y

I havent cleaned the solonoid but it looked fine when i inspected it, there was no oil contamination anywhere i could see includinng the pipes

sg72

Check the hose from Boost solenoid to Turbo .

Mines had been having these symtoms lately.

Hose was split. Causing overboost and fuel cutout.

Just a thought.