currently wen im boosting or reali giving it the beans , the engine seems to jump and and cut out and imeadiatly jump back into life, this fault is onli on boost , its a 93 impreza wrx , various mods , headers, de-cat ,induction -blitz DV, runin about 1.1 bar any ideas????

 

Probably either of the below:

a) Hitting fuel cut because of overboosting i.e. exceeding the MAP sensor's 1.2bar rating. Is the cut violent like 'hitting a brickwall', which can throw you forward against the seatbelt?


b) The boost is blowing out the sparks momentarily.

Remove and check overall condition of the plugs. Clean them up if still serviceable. If not then get new ones... get the colder NGK PFR7B.. Before refitting, regap them to 0.65mm (to compensate for old coilpacks and 1.1bar of boost). Talking of which, check the state of all 4 coilpacks whilst they're removed. Any obvious hairlines, splits or cracks, then replace as necessary...

 

I had the same sort of problem, mine was dying around 5000rpm. It turned out to be one of the ht leads. So might be worth checkin your ht leads and your coil pack.

Hope this helps.

 

Sound to me like you are hitting boost cut.

Mine has done it a couple of times lately in this cold weather, the last time it did it I managed to watch the boost gauge and it had reached 1.1 as it did it.

Ady.

 

what ecu is it running? is it chipped? boost controller?

....is it like hitting a brick wall when it happens? (quite violent)


sounds like it could be fuel cut.

 

LOL just added that to my post

 

doubt it is a spark plug/coilpack issue at 1.1 bar

 

should I edit mine now.....lol



nah - bet I got it right first time

 

had this problem after fitting a chip yesterday i solved it by turning the actuator down one turn. hope this helps.

 

You'd be surprised.

Motor can 'tolerate' slightly dodgy coilpacks and/or plugs at std 0.8bar boost. But when upping to 1.1bar, it can really show up any defects in the ignition system by misfiries, etc...

EDIT: As just perfectly illustrated by scooby1508 above!

 

dont get me wrong, it is definately a possibility.

I've only ever seen issues when starting to go over 1.3.

 

was yours missfiring or hitting fuel cut?