Guys,

Thanks for all your help in diagnosing the problems with my MY94 WRX. I won't mention names, but many members contributed.
Findings: After fitting a GGR K&N induction kit (the KIT, not just AF!) I had 'head-butting' fun with total loss of power between 4K-5K at full throttle. This was due to a (freak) lack of air being diverted to the air flow sensor. All air was going directly to the turbo! Good for psi but no good for my whiplash!
This was solved by placing a restrictor (somewhere) in the air flow therefore balancing the split of air. I not have a healthy 12/13psi boost available on tap, and the car is more responsive. I expect to have arount 271-275bhp after this upgrade.
I would also like to thank the guys at GGR (pisspot!) for sorting this out. They didn't charge me a penny, obviously, as this was a 'freak design incompliancy' (is that a new word?)
I still have check engine problems though. I have check all hoses (tightened a couple of clips) and the errors are now more pronounced than before. I get this on low speeds approaching idle (<3K, typically 2K) with little or no throttle. I suspect an incorrect amount of air being registered at this rpm. Any ideas? Error codes are: 23,24,31. Email replies welcome.

pilch

 

Hi Pilch

All of this is very interesting.

First you say that you have an induction KIT, rather than just a filter, but the full induction kit requires the relocation of the power steering pump, so I assume you just have the filter.

GGR have said that a freak design problem meant that air was "going around your air mass snesor and straight to the turbo... good for boost, but..." Sorry, but this just isn't possible. The AMS sits in the middle of the air flow.

The error codes that you list are...
23 - Air mass sensor failure
24 - Idle air control solenoid valve
31 - Throttle position sensor failure

It could also be the wiring to anyone of these.

Hope the codes help, surprised that these weren't attended to when the Manifold Pressure Sensor problem was fixed.

270+ does seem a bit ambitious, as you started with approx 240bhp and most people only get a couple of bhp (peak) from a decent filter.

 

Apologies if I should know this, but how do you find out what the error codes are and how do you decode them to find out what problems exist?

 

It sounds like Pilch is trying to tell us that his overboost problem has been solved by playing with the flow restrictors in the wastegate control hosing.

I had a similar overboost problem with my sti 3 recently, which I eventually fixed by fitting a larger bore restrictor in one of the control hoses. Don't try this at home, kids!

 

Hi Pete,

No, I have a kit, in that all the hoses are supplied and the flame box etc are removed. The AMS is retained. All other hoses in line are replaced until the hose to the turbo itself. The power steering pump was not removed.
The engineers couldn't reproduce the error codes when the car was at GGR. Next time I will drive! I can't stop the damned codes.
I had a dyno test at PE and clocked up 263bhp (with Magnex BB). Taking that, adding circa 5bhp from the induction kit, plus the 3psi extra boost granted due to the restrictor, and I calculate about 270+ bhp. I would like to get another dyno test for my own peace of mind!

I doubt very much that wiring is a problem, as I have checked all points and cleaned them. The problem only occurs when the engine is hot, and there is little throttle pressure. Also, the revs must be at ~2.5K or so for the error to occur.
HunterB - there are two cables under the steering column: green pair and black pair. Green is 2 wire and black is single. Connect the black plugs and engage the ignition. The Check Engine light will flaash to indicate the error codes - long flashes for 10's of units, short for single units (ie 24 is 1--1--1-1-1-1). The green plugs are to be used in conjunction with the black plugs for resetting the ECU. You will only need to check the error codes if the Check Engine light comes on whilst driving. Check this URL for codes: