Stagea Surging?

[ants888]

just wondering if anyone can help me with a problem with my rs4 s stagea?

it's surging while driving.

i already done coil packs . changed to splitfire.

using boash double platniums with gap 1.0mm. splitfire coils should jump that gap easy. no mod's only panel filter

i'm thinking air flow meter?

it seems to drive ok when cold but then if it hit a bump it starts to surg? and once it gets warm

but saying all that it comes and go's.

i also read that the soldering joints can break inside air flow meter. which would explan why it comes and go's

thanks ant

[~R33AzzA~]

It sounds like something elecrtical, take it to your mechanic he should be able to find out whats goin on.

[Duncan]

It might just be a stagea thing, mine is similar. basically the ECU has much lower threshold for change than the equivalent 33 gtst one even on the same motor. mine started surging with only a unifilter panel filter and radiator air guide, and got much worse once i fitted a turbo back exhaust. the ecu sees an unusal voltage from the AFM for the load it is seeing and goes very rich, and retards the timing.

I fixed it temporarily using a HKS fuel cut defender, but am about to change the ECU to sort it properly long term. check out the stagea section lots of people have had similar problems

[ants888]

It might just be a stagea thing, mine is similar. basically the ECU has much lower threshold for change than the equivalent 33 gtst one even on the same motor. mine started surging with only a unifilter panel filter and radiator air guide, and got much worse once i fitted a turbo back exhaust. the ecu sees an unusal voltage from the AFM for the load it is seeing and goes very rich, and retards the timing.

I fixed it temporarily using a HKS fuel cut defender, but am about to change the ECU to sort it properly long term. check out the stagea section lots of people have had similar problems

Thanks heaps Duncan.

Every bit of info helps. I noticed it was doing the same thing even when it was stock with standard air filter, cars only done 58000kms and it looks genuine.

I,ve done a few tests cheked fuel flow at 3000 rpm and it was 2.1 litres per minute, mixtures seem to be a bit lean at light throttle but ok at full throttle.

I've removed and cleaned air flow meter (not keen on pulling it apart until i've got another one to test with, but my mate has one I can test with so will do that on the weekend) if it still does same thing then I think you might be right about the ECU.

If that's the case Ill get a HKS fuel cut defender or source another ECU as you suggest.

Would the R33 gtst ECU be the same as the Stagea, also my Stagea is a manual so obviously I would have to go for a manual computer but I have heard that you can use Auto ECUs on manual cars, mine is the RB25 Neo motor. Is there any other ECUs that will do the job??

Another mate of mine also suggested throttle position sensor can also cause same problem, but if it was the throttle position sensor I would have thought it would have only done it on light throttle not through to full throttle??

But now that you say that it richens the mixture that makes sense to me as when I first got the car I was getting 550 km per tank and even 600km out on the open highway. Now I'm getting around 480km per tank and it seems to be doing it worse now than when I first got the car.

I'm at a bit of a loss, but I think I will just have to use the process of elimination.

If you can think of anything else that it might be please let me know.

Cheers

[wolverine]

if you are in sydney and want to try another standard RS4S ECU i have one lying around.

Edited June 3, 2008 by wolverine

[Duncan]

no unfortunately the r33 gtst had the same motor but different loom. you need to try another stagea one like wolverine's one.

[ants888]

if you are in sydney and want to try another standard RS4S ECU i have one lying around.

Thanks for the offer but i'm in Adelaide. Going to test air flow meter tomorrow , Will let you know how i go.

[ants888]

It might just be a stagea thing, mine is similar. basically the ECU has much lower threshold for change than the equivalent 33 gtst one even on the same motor. mine started surging with only a unifilter panel filter and radiator air guide, and got much worse once i fitted a turbo back exhaust. the ecu sees an unusal voltage from the AFM for the load it is seeing and goes very rich, and retards the timing.

I fixed it temporarily using a HKS fuel cut defender, but am about to change the ECU to sort it properly long term. check out the stagea section lots of people have had similar problems

Gday Duncan.

just thought I would let you know what that surging problem was, turned out to be tyre size. even though both front and back were both 235/ 45/ 17.

They were a different brand and the rolling diameter was different only by 35mm.

This was throwing the 4wd system out causing the surging/hesitation/shudder.

If you know anyone with a surge/hesitation/shudder problem with there stagea, r33 or r34 check this first and also the 4wd oil reservoir located in back of wagon on right hand side, must be checked after a drive, because when cold it will show an increased amount.

[ants888]

if you are in sydney and want to try another standard RS4S ECU i have one lying around.

G'day Wolverine.

Thanks for your generous offer but just thought I would let you know I found out what that surging problem was, turned out to be tyre size even though both front and back were both 235/ 45/ 17 they were a different brand and the rolling diameter was different by 35mm. This was throwing the 4wd system out causing the surging/hesitation/shudder.

If you know anyone with a surge/hesitation/shudder problem with their stagea, r33 or r34 check this first and also the 4wd oil reservoir located in back of wagon on right hand side, must be checked after a drive, because when cold it will show an increased amount.