Wrx Surging

[RBwhatever]

Long story short.

My brothers got a MY00 WRX, it has a slight hesitation or a miss down low in the revs when its not on boost and when its cold. He's tried new plugs and leads and fuel filter to no avail.

He does however have an S15 pump in there (came in the car when he bought it). It has a FMIC, turbo-back exhaust and pod in the mod department.

Would it be better if he's throw in my Stock R33 pump in? Would this help with the hesitation?

ps, I'd be posting this on rexnet except they won't accept my email to sign up.

Cheers guys

[stolen_s15]

Check/clean the coils and ignition system.

[RBwhatever]

Ok I'll note that down. Thanks.

Its weird because the spark doesn't break down in the higher revs at all.

Edited September 27, 2007 by KeyMaker

[TTT]

walbro pump would be the smartest cheapest option for a pump for a rexy.

[blind_elk]

There might be a "flat" (wear) spot in the TPS that sends the "wrong" signal to the ECU.

[RBwhatever]

walbro pump would be the smartest cheapest option for a pump for a rexy.

Yes it would be. But we're trying to get this one down to a cheap as possible solution, but if it really came down to it and we really had to we'll get walbro. Better to do it right the first time.

But the R33 pump has got be better than the S15 pump wouldn't it? It'll be a larger sized pump than the stock wrx and s15 pump. Might be a touch harder to fit. I'm not even sure it's the problem, it probably isn't. Just another possibility maybe.

There might be a "flat" (wear) spot in the TPS that sends the "wrong" signal to the ECU.

Wear spot on the TPS? That's a new one to me. Please elaborate. How can I check the TPS?

Cheers guys

Edited September 27, 2007 by KeyMaker

[RBwhatever]

Anyone else have any ideas?

[Hijacker...]

If it's below 180rwkws which it will be the S15 pump will be fine unless it fudged! So he could try your R33 pump to see... No cost What pumps do they usually fit in the Rexy's? If an 040 fits your R33 pump will!

[S04R3R]

If i remember right 040 wont fit without mods, you can pick up walbro pump kits off ebay and formums liek rex met for around $125. I have one on the way for my liberty and they are pretty much the same set up.

AFM's f**k up on them a fair but as well.Try cleaning it out and see what happens.

[RBwhatever]

I don't think its the fuel pump. If it was it would break down even more under load.

It could be the AFM, but it only seems to happen when the cars cold, when it warms up its fine.

[tonyzx7]

I don't think its the fuel pump. If it was it would break down even more under load.

It could be the AFM, but it only seems to happen when the cars cold, when it warms up its fine.

Common problem with the MY99-00 , check airflow senser and clean............

[sl33py]

slight hesitation or a miss

Is it missing at idle or is there hesitation (or actual misfiring) in the low revs when accelerating? More info.

[Willo]

I don't think its the fuel pump. If it was it would break down even more under load.

It could be the AFM, but it only seems to happen when the cars cold, when it warms up its fine.

I had the same problem in both my GT Foresters but much worse, it was the AFM both times. How many kms has it done? It is a common problem around 150,000kms+.

If it is the same AFM as the Forester (the '00 model one I just bought was the same as the WRX) it will be around $200 for a '98/'99 model and $750 for a '00/'01/'02.

edit: Also note, if it is the AFM is it running extremely lean (Forester was running 17 AFR and pinging audibly). Get it fixed asap before it costs you a motor.

Edited October 25, 2007 by Willo

[RBwhatever]

Is it missing at idle or is there hesitation (or actual misfiring) in the low revs when accelerating? More info.

It hesitates(a single hesitation) low in the revs when accelerating.

I had the same problem in both my GT Foresters but much worse, it was the AFM both times. How many kms has it done? It is a common problem around 150,000kms+.

If it is the same AFM as the Forester (the '00 model one I just bought was the same as the WRX) it will be around $200 for a '98/'99 model and $750 for a '00/'01/'02.

edit: Also note, if it is the AFM is it running extremely lean (Forester was running 17 AFR and pinging audibly). Get it fixed asap before it costs you a motor.

So you reckon just a clean won't fix it? What if we re-solder all the points on the PCB board like when you fix skyline AFM's?

[Willo]

It hesitates(a single hesitation) low in the revs when accelerating.

So you reckon just a clean won't fix it? What if we re-solder all the points on the PCB board like when you fix skyline AFM's?

Cleaning doesn't do anything. I have no idea where the failure point is so couldn't tell if it would fix it or not.