boab type ra Posted February 18, 2008 Posted February 18, 2008 Can someone help me plz! Now and again my scooby feels as if it hits a brick wall when i floor it, a friend said it could be the over boost valve can anyone suggest a solution plz?
thewelsho Posted February 18, 2008 Posted February 18, 2008 Can someone help me plz! Now and again my scooby feels as if it hits a brick wall when i floor it, a friend said it could be the over boost valve can anyone suggest a solution plz? Happened to me when I installed a bigger turbo. I decided to boot it before I got it mapped to see what would happen. A very foolish thing to do. Just as you said, felt like I slammed into a brick wall. I experienced boost-cut as the ECU wasn't able to deal with the extra boost so in the interest of protecing things, it simply cuts the power. So yeah, sounds like over boosting. My CEL came on as well though, but went out about 5 hours later.
johnnyr6 Posted February 19, 2008 Posted February 19, 2008 What year of scoob is it? Do you have a boost gauge fitted, if so what is the peak boost? It could well be fuel cut due to too much boost. Also welcome m8, what car do you have, may have seen you around. Johnny
boab type ra Posted February 19, 2008 Author Posted February 19, 2008 What year of scoob is it? Do you have a boost gauge fitted, if so what is the peak boost? It could well be fuel cut due to too much boost. Also welcome m8, what car do you have, may have seen you around. Johnny thanks av no been a member for long but i hope 2 meet you guys and put faces 2 names. It`s a 1994 wrx type ra, the peak boost is about 14 psi if thats any use.
johnnyr6 Posted February 19, 2008 Posted February 19, 2008 (edited) If i've calculated correctly that's about 0.95 bar which, giving for discrepancies with the gauge is about right. 0.9 bar is the standard pressure so you shouldn't be getting fuel cut. your gauge could certainly be under reading. Does the ecu have an aftermarket chip in it?? Does the power come back in after the hesitation or do you have to back off (i.e is it a stutter or total loss of power)? Oh, if you see a silver classic with white wheels (as in the pic) give us a wave. Johnny Edited February 19, 2008 by JohnnyR6
boab type ra Posted February 20, 2008 Author Posted February 20, 2008 If i've calculated correctly that's about 0.95 bar which, giving for discrepancies with the gauge is about right. 0.9 bar is the standard pressure so you shouldn't be getting fuel cut.your gauge could certainly be under reading. Does the ecu have an aftermarket chip in it?? Does the power come back in after the hesitation or do you have to back off (i.e is it a stutter or total loss of power)? Oh, if you see a silver classic with white wheels (as in the pic) give us a wave. Johnny I don`t know about the chip, i got the car from crd they said it had been remaped. It`s a stutter but usually let off. Mines is a white type ra with a full monza kit and silver rss wheels.
johnnyr6 Posted February 21, 2008 Posted February 21, 2008 If it's a stutter, it may be the maf or one of the coilpacks. Do you run an induction kit? I doubt it's been remapped unless it has an aftermarket ecu which i'm sure they would have mentioned. You can remap the early ecu now but it's relatively new. You had your car a while? i think i saw it about a while back. Johnny
boab type ra Posted February 21, 2008 Author Posted February 21, 2008 It has an apexi induction kit. Av had it 3 years, got the kit fitted and resprayed during the summer.
wilky Posted February 21, 2008 Posted February 21, 2008 It has an apexi induction kit.Av had it 3 years, got the kit fitted and resprayed during the summer. If you take the coilpacks out take the rubber protector off the ends and check for hairline fractures on the lip of the packs where the touch the plugs, overtightening them on istallation or servicing can cause them, this causes stuttering. Also its worth getting a decent set and trying them in the car just incase the are shagged or one is shagged, this can cause the stutter. When you tighten the nuts just nip them once they tighten dont crank them down or you will cause problems like fractures. Also take you plugs out and have a look at them maybe they are gubbed???? This has also caused stuttering, replace them with NGK PFR 7B set on a gap of .68 I always found this the best when not running serious boost. If none of this solves the stutter well look at something else. Callum W
johnnyr6 Posted February 21, 2008 Posted February 21, 2008 lol, how's things sir?? Anyway as Wilky said checkout the coilpacks. The apexi ind. kit is good so shouldn't knacker the maf but it's always worth checking that to. Make sure there is no crap on the wires in the maf but be careful as they are pretty fragile. and not cheap. johnny
boab type ra Posted February 22, 2008 Author Posted February 22, 2008 Thanks guys i will check the coilpacks at the weekend.
wilky Posted February 23, 2008 Posted February 23, 2008 Thanks guys i will check the coilpacks at the weekend. Hello Johnny, things are good, lol. As Johnny says check the maf as well, this has similar effects but it can also manifest as the car running really rough on start up as well which is an indicator of the maf on its way out. MAFs are dear to buy and hard to find sometimes second hand in good nick so best way to check is find a pal with a similar car and similar MAF and try his on your car and see if it solves the dramas.
boab type ra Posted February 24, 2008 Author Posted February 24, 2008 Don`t know anybody way a scooby but i will give the maf a check. Had the car out at weekend and it ran like a wee sweety no problems so am planning new plugs for it next weekend. Thanks guys for all the help.
johnnyr6 Posted February 25, 2008 Posted February 25, 2008 What? you must be as freindly as me...lol There are loads around Law too. Johnny
turbo2000wagon Posted February 25, 2008 Posted February 25, 2008 Could be all of things mentioned, MAF, overboost fuel cut etc..MAF's seem to give different symptoms when they fail but mine was more of a misfire than like hitting a wall on boost. I did have the boost solenoid stick a few times and that was like hitting brick wall, it seemed to happen overtaking when I was really hammering it but then would almost instantly fix itself. Incidentally if the MAF is knackered it won't affect your boost so see what your gauge does when it next happens, if the boost doesn't dip it's not the MAF, coil paks or plugs.
johnnyr6 Posted February 26, 2008 Posted February 26, 2008 boab, check out the coilpacks and plugs, if it's not them give me a shout and i'll sort you with a maf you can try to rule that out. To me it sounds like the coilpacks. Johnny.
supersi Posted February 29, 2008 Posted February 29, 2008 HI. Just to throw another ball in the pitch.... Noting that its a 94 wrx and assuming that perhaps with age.... the vehicle may have some perished rubber hosing, mainly that, to and from, ure intercooler. It would be advisable to inspect the condition of these as any signs of decay will cause problems under hard acceleration/driving and may not be apparent under more sedate acceleration. Check any other such hoses that are subject to varying air pressures also. This could be the easiest thing to check before buying and or swoping parts that may not be required. Recently had experience along these lines and this proved to be the cause.
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