Power Issue

willtech · Post by **willtech** » Fri Dec 22, 2006 8:49 pm

im having power issues with my gpx, it seems to be restricted when the mivec kicks in.

getting nice acceleration up till 5500rpm but then it dies in the ass, keeps reving but no acceleration.

ive got a mivec controller and was thinking this might be causing it to throw the timing out?

any ideas on what it might be are much appreciated

payaya · Post by **payaya** » Fri Dec 22, 2006 9:35 pm

stops accelerating or slows down????

tj2709 · Post by **tj2709** » Sat Dec 23, 2006 12:33 pm

i believe he meant after the mivec kicked in, it still reving up to 8000rpm, but the car not getting any faster...so the car not stop..or not slowing down...i got the same problem before, mine one was the clutch...i change mine and so much different after.

RedlineGX · Post by **RedlineGX** » Sat Dec 23, 2006 2:12 pm

I would go with maybe the clutch too but would need to know more first.

willtech · Post by **willtech** » Sat Dec 23, 2006 2:15 pm

stops accelerating, but still revs out. surely this isnt normal?
correct me if im wrong but i thought u were ment to get more acceleration when the mivec kicks in?

im going to take put it on a dyno in the new year to try figure out whats wrong

to me it seems like a timing/tuning problem, but was also thinking it may be an exhaust issue i.e cat convertor is f*%ked and may be restricting the outflow??

if the engine was loosing compression would it do this?

willtech · Post by **willtech** » Sat Dec 23, 2006 2:20 pm

sorry ppl i should have put this in the help section

clutch has been replaced about 20000kms ago
also new timing belt

spetz · Post by **spetz** » Sat Dec 23, 2006 5:31 pm

Check that your cat is ok and exhaust flows properly

tj2709 · Post by **tj2709** » Sat Dec 23, 2006 9:45 pm

what clutch did u put...?? just a plain after market one? or original factory fto clutch...i change mine one to heavy duty sports performance by exedy. i really dont think put it into dyno would help just a waste of money...just go to a trust worthy mechanic...they will help u more.
ps : u should machine the flywheel...if u change your clutch. dunno if u ever do that...but u suppose to.

m3nG · Post by **m3nG** » Sat Dec 23, 2006 11:13 pm

Have a look to see whether the revs flow freely up past the 5500 and beyond.. if you see it drop back just a fraction then swing back up most likely its your clutch otherwise possibly and intake / outflow issue..? i had a blogged cat once and it was doing the same thing.. the honeycomb crumbled in there and was restricting the outflow.. if you notice any rattling at all then it could be the cat..

mr-charisma · Post by **mr-charisma** » Sun Dec 24, 2006 1:40 pm

I have the same problem with my car;

Put my foot down and it gets to 5500-6000RPM and just revs out, makes a really bad sound, then I have to back my foot off the accelerator before I accelerate again.
It seems to me like its revving too much for the gear its in, but it doesn't explain why it would do it sometimes and not others (Not often that it doesn't do it though) I can control it better in Tiptronic and shift up/down the gears when its revving too hard, but there has to be something that can be done to make it not do it - especially if not everyones FTO does it.

I have tried, resetting the ECU (In case it was learnt driving behaviour from the last owners) Didn't work
Letting the car warm up for half an hour of driving - cause someone suggested that it is because the MIVEC needs to warm up before you Rev it really hard. I think that it does help, but not sure to what extent.
I've also bought a MIVEC controller & will have to have it tuned right first, but I am hoping the changing the amount of AIr/FUel getting into the engine will help the situation.

I will have to have it checked by a mechanic first to see if theres anything they can do about it though.. I would suggest that you do the same.
Tuning can be more expensive.

khunjeng · Post by **khunjeng** » Sun Dec 24, 2006 4:52 pm

sounds like a slipping clutch...if it just free revs with no power.

well thats all can think of without actually looking at it...

willtech · Post by **willtech** » Tue Dec 26, 2006 11:47 am

ok im closer to figuring it out

thanks for the advice all, but its definitely not the clutch, i own a manual and have driven manuals with bad clutches before this isnt the prob.

took it for a drive yesterday and heard a slight rattle in the exaust while accelerating so i think i need a cat.(drummy kinda sound)

now too add to my problems, theres a discrepency between the mivec controller and the car tacho. the mivec reading is higher than the tacho i.e when @ idle car tacho is reading about 7-800rpm which seem to be normal, but the electronic mivec is reading 12-1300rpm, sometimes 1500.

When sitting there in idle the exhaust smells like unburnt fuel, initially i thought the person i bought the car from had it tuned to run rich(which is obviously better than lean)
what i think is happening is that the mivec controller is telling the ecu the wrong info, opening the mivec earlier in the revs, but when its reading 6000-6500rpm the controller reads around 8000rpm causing the ecu to think its redlining (and a rev limiter is kicking in, not sure if they have one?)

Seeing the mivec controller was already installed when i bought the car, i dont know what im looking for or how it was wired into the ecu?

what can i do????

Post by **Bennoz** » Tue Dec 26, 2006 7:32 pm

Sounds like the 02 sensor is shot..

SchumieFan · Post by **SchumieFan** » Tue Dec 26, 2006 10:01 pm

Bennoz wrote:Sounds like the 02 sensor is shot..

DAMN YOU!

either the o2 senser or 1 of the mivec sensers in the cam case (or both?)

athough if it was a mivec senser you would just have normal acceleration.

check the diagnostic code

payaya · Post by **payaya** » Fri Dec 29, 2006 2:11 pm

Cat Convertor could give a sense of no power up high.

willtech · Post by **willtech** » Sat Jan 20, 2007 12:43 pm

heres an update

over christmas cat overheated and crumbled blocking the exhaust

getting cat replaced on monday, then its off to the dyno tuesday to see if theres any errors
the tuner guy was saying that if it was a sensor, there shouldnt be a discrepency in the rpm readings (but running rich caused the cat to melt)
i suppose we'll see on tuesday

thanx again for the advice everyone, ill post what was actually wrong when its diagnosed

payaya · Post by **payaya** » Fri Jan 26, 2007 9:48 am

thanks me!

Also the rest of your exhuast should be fine, just replace the cat.