nick1977

Hi all

Typically, the problem I am having has become apparent on a Saturday eve, with no hope of getting hold of someone until Monday!
I had an engine rebuild completed 2 weeks ago on my Import WRX facelift from 1996. I have been strictly sticking to the below 4000rpm guide and have given very light acceleration.
About three days ago I went over a speed hump (not fast!) and it felt like the engine cut for a sec then came back. The check engine light came on and then went out a few moments later. Thought not much of it, until today when it cut a couple of times when under light acceleration. Once when pulling away, and again when at about 2500rpm in 2nd gear (I think). It was like hitting a wall or something, almost as if the brakes suddenly came on. Again the check engine light came on and went out after a few minutes.

Only other symptoms are that it sounds slightly rattly when accelerating, but sound stops immediatley when foot comes off accelerator. I get a whining sound in a couple of gears between 3000-4000rpm when under light acceleration. Idling seems a bit off too, as it falls to anything between 1000 and 1200 if you rev it slightly in neutral - no consistency. Even when idling it seems to speed up and slow down slightly as though it's pulsing. Plus the engine seems to be shaking *very* slightly. Not madly like it was b4 rebuild tho!

Tank is almost full with Shell VPower, but was running on 95 with octane boost the night it first happened.
I'm no technical expert so not sure if all these symptoms refer to one or many problems, but if there is anything obvious to check please let me know.

At the rebuild it also had:

Sti Turbo
Sti MAF
Idle Control valve
Ported headers
Lightened flywheel
Xeedy clutch

Already had also Sti injectors. After running in, it is due to have new ecu and remap.

Don't know if any of that helps to eliminate anything but heres hoping

Thanks for any advice
Nick

banny sti

iTrader: (68)

Well your current ecu will be mapped for 380cc injectors and 97 onwards sti injectors are 440cc, so for each injector cycle now you are flowing more fuel.
This would cause the rough running and possiblly why the car is cutting out as it will be running very rich.

Banny

nick1977

Thanks Banny

Is it likely to be due to the rebuild and other parts being replaced that this is now apparent? The car has had the sti injectors since before I bought it in May, and although it was running badly (hence the rebuild!) I never had the cutting problem or the check engine light coming on.

Nick

banny sti

iTrader: (68)

You need to find out what code the car is displaying with check engine light, this should help you locate the problem. Take it back to garage that has carried the work out and see what they advise and in the meantime drive the car as little as possible.

Banny

nick1977

Cheers Banny

I can see a phone call rather than a visit to start with, as they're 80 miles away

Nick

Fuzz

Are you saying it has..
A different turbo to standard
A different MAF sensor to standard and
A different set of injectors than standard

But has a standard unmapped ECU????

555Rob555

Look for the simple stuff first. If a bump caused the first problem, it could well be just a loose connection on a sensor making the CEL come on. Get the faults read, and that should help you with where to start looking.
Once the cutting out is sorted, a remap will sort the other problems, or at least tell you what is wrong.
Hope that helps

nick1977

Yep!
I was a bit of a novice when I bought it (not much better now!), and the previous lady owner didn't seem to know a lot about it either, believing it to be standard WRX.
I assume it has an unmapped ECU. I think it is safe to assume that all the non-standard stuff is what resulted in the rebuiild being needed. I have been advised by the company that did the rebuild that I need to run it in to 1000 miles, have service, then "loosen it up" progressively over next 500 miles, then new ECU and remap can be done.
I'm not going to say who has done the rebuild at this point, but fair to say they have a good reputation on here, and so far my experiences have been very positive.

Also thanks Rob for your advice.

Nick

Bob Rawle

First of all the exact car model isn't clear, if its a 1996 model thats from Sept 1995 to Aug 1996, so early in 1996 its one thing and later another. Stated as being facelift so that makes it a 1997 (should), all MY97 cars had 440cc injectors as std, even the WRX iirc. So the ecu should match. Maf could be different possibly. If its a larger bore maf running on an ecu specified for the smaller bore then it will run lean all the time. Slightly rattly, well depending on load that could be audible det especially if it was loaded enough to be on boost but even a car just off boost and closed loop can det if its too lean. The "Sti" turbo for MY97 was a VF23.

Suss the codes and get the fueling checked out to see what afr its at with some det cans attached to make sure its ok, then the mechanical noises can only be down to the rebuild. Even if there is no cel now there should be historic codes stored.

Don't "accept" that it should be run for 1000 miles before mapping, yes some miles need to be done for a full on mapping setup but the replacement ecu can be fitted and a running in map put on it limiting boost right now, otherwise you may end up with tears. Not a problem for someone to do especially if the car isn't std and uses mixed parts.

best regards

bob

Fuzz

Must admit it does sound odd to have been sent away with all those non standard parts and not at the VERY LEAST a "base map" put in.
As bob says, get that (and those noises) checked out pronto !
I do wonder when you say "I think it is safe to assume that all the non-standard stuff is what resulted in the rebuiild being needed. and then carry on driving it after a rebuild without having anything done about it.



Andy

nick1977

Fair point Andy, but I was going on the advice of the company that did the rebuild. When you haven't got much technical knowledge all you can do is put yourslef in the trust of the experts! I assumed that the engine was unlikely to incur any damage due to the fact it was being given light load and kept under 4000rpm.
I will speak to the people concerned on Monday anyway and try to determine the best course of action. As I said earlier, it is unfortunately an 80 mile trip to the place it was done, which doesn't help matters!

Nick

nick1977

Sorry for not being clear. It was manufactured late 1996, and is a facelift version. Front end is different and it has the different steering wheel with airbag and anti-lock brakes. Not sure what other differences there were but these are the ones I am aware of!
Thanks for the other advice also.

Nick

nick1977

One other point that probably has no bearing on anyrthing. One of the rear speakers has stopped working. Could be a dodgy earth somewhere.
Just thought I'd mention as the silliest thing can sometimes be the answer!

Nick

nick1977

Just thought I'd update. I was told how to do diagnostic test (useful for the future!) and found it was code 23 - MAF sensor. Was sent another one by courier and fitted it, reset ECU by disconnecting battery for 1 hour, and now no fault code, so hopefully all is good.

Nick

StickyMicky

same model as mine then
mine is a late 96 car
MY97 model

Large bore MAF and 440 injectors are as standard on the wrx