mul

hi everyone
i have a really big problem with my 94 WRX .
Every time its on full throttle, at about 5500 rpm it splutters and sometimes even cuts the ignition (the rev counter needle just drops to zero very briefly).
I have changed the spark plugs and fuel filter and checked the MAF sensor connection all of which are fine and have made no difference. The only other explanation is that i recently changed the cam belt, and although all the markings were lined up, maybe the timing may be out by a tooth. But surely if the timing was out, the engine would be down on power and running roughly ALL the time. I really don't know what else to do. The next step is to take it to a specialist to see what the hell is going on.

Can ANYONE help me?

cheers

chris

Richiehash

if the rev counter drops to zero this sounds like an intermittant power failure had it once on a cav turned out to be a loose crimp on a power lead which was deflected on load (engine moving on mounts) making and breaking the connection. same applys to earth leads . hope its this simple .
richie

mul

cheers richie

i'll hunt around the engine bay to see if we have knocked/damaged a connection somewhere

AJbaseBloke

Could it be the O2 sensor?

Hope this helps.

Cheers.

cryptwalk

i had a problem similer to this, when on the motorway and i put my foot down the rev counter cut to 0 and then it would just flick back up to what it was before.
Whilst at 0 there was no response from the accelorator then after about 5 seconds it would kick back in.

Also i had it holding backoff boost most of the time, it was intermittent sometimes it would go like a rocket and other times like it had no turbo.

After 12 months of spending money (lots) taking it to people who didnt have a clue,
i tried a new ecu eurrekka problem solved.
The ecu was causing overboost and shutting down the engine, i got a second hand one for 150 and have had no problems since thank god making me very very happy again

My car is a 94 wrx so you may have the same problem, i changed the plug's aswell thinking this could be the problem.

Anyway try borrowing a ecu see if it help's.

[This message has been edited by cryptwalk (edited 21 May 2001).]

mul

thanks everyone,

hopefully i'll have it sorted soon

chris

Adam M

Can you explain the problem exactly, cos some of the symptoms sound like coil pack failure.

On mine it consisted of stuttering and misfiring when you floor it. More so in higher gears. mine didnt last long enough for the revs to fall, but they did stop climbing.

mul

i'm not sure it is coil pack failure as the spluttering isn't really consistent. Also it seems to cut the ignition (rev counter drops to zero) then cuts back in - revs continue to rise. We do have a theory - there is a sensor behind the crankshaft pulley (can't remember whats its called) that if moved or knocked in any way, could cause this problem. Considering the amount of times we had the cam-belt on and off, i think that this is the likely culprit (i hope). Otherwise i may have to look at the coil packs as a cause.

Jim Dunleavy

I think you're on the right lines re the crankshaft sensor, also check the camshaft sensor as well, it's on the rhs as you look from the front, usually though the check engine light will also flash, try reading the ecu memory.

mul

cheers jim

I've just looked at a good site

GavinP

Mul,

Have you got a boost gauge fitted ?

The symptoms sound like the "fuel cut" which the ECU uses to limit boost if it goes over 15.5 psi....

Thanks

Gavin

Jim Dunleavy

Look under the dash behind the steering wheel, you'll see two connectors, single pin black and two pin green, connect the black ones, turn on ignition, look at the engine check light, it will flash a code if there is a fault, if no fault the flashes will be constant. ie if fault code 23 you'll get two long flashes followed by 3 short ones.

mul

cheers everyone

i checked the ECU and it turns out that it is reading an error code 23 - MAF sensor. Of course i only did this after i'd checked the crankshaft sensor, cambelt sensor, wastegate solenoid, spark plugs, fuel filter and coil packs bugger !

oh well - at least i know what it is now

wallsy

could sound like your running more than 15-17lbs boost and maybe the boost cut defender might be doing this

Wallsy