My '93 wrx is occasionally cutting when boosting hard!

If I drive real steady for ages then cog and foot down it's pretty much guarenteed to cut but if I slowly build up revs/boost for a couple of mins then nail it it's fine (for a while).

Diagnostics is only coming up with map sensor, changed this, but the problem is still there!!!

any ideas guys????

 

Coil pack???

 

wouldn't coilpack come up with fault code?

and why the map sensor fault code?

 

What boost are you reaching?
You may be hitting boost cut which is there to protect your engine. Remove the boost cut at your peril.
Has the car been altered in any way with the addition of a bleed valve for instance.

 

I'm currently running a chipped ecu (boost cut raised/removed) 1 bar

have run this ecu in past with no problems!

have had several standard ecu's on car - all do the same......

all started after fitting......then removing because it was knackered a apexi afc

 

anyone?

 

Sounds like fuel cut
don't foget the weather is cooler than it were a few weeks back ,so the air is more dense which can make your car over boost

 

no its not fuel cut,

 

why not.


Andy

 

chip removes the fuel cut,

have tried fuel cut defender on there as well

 

anyone???

none of me mates can figure it out

 

requires professionals, not mates


Andy

 

try your spark plugs. make sure they are gapped at 0.7mm. I had the same problem. Took quite a while to figure out it was spark plugs that were gapped at over 1mm. Changed em and the car rev'd freely all the way to the redline.

 

it does sound just like fuel cut.. If you build up gently the boost doesn't spike as much and so wouldn't cut. But if you just floor it, it will spike and cut! I would get it checked by a reputable garage like api or scoobyclinic.

 

thanks for response

......when I said build up gently, I meant slowly driving harder and harder and then pin it through the gears it's usually ok for several blasts untill I start driving steady again for a while and then pin it and it'll cut (think that makes sense)

thanks again

Mark.

 

How did you connect the apexi afc? Is this spliced into the ecu loom? (not familiar with the afc but I know the avcr is), If so and you say it was faulty maybe it was wired up incorrectly as I know the wiring instructions can be a little bit upside down in the apexi manuals. Then depending on how you had the afc connected there could be a short going to the ecu. Worth a check imo

 

Try changing the plugs

 

yep the apexi was wired into the loom (pretty sure it was correct) - all removed and tidied up now!

why do you think the problems are down to plugs? (gotta be worth a try though) and why the 45 fault code????

cheers guys

 

Because it sounds like an ignition problem