Impreza STi 2001 problem

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Jul 5, 2003 | 02:06 PM

Moorey

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Impreza STi 2001 problem

Hello from this side of the pond!!
I have a problem with the above with the fueling at idle being excessively rich. This car should be fitted with EOBD but my reader wont look at it. I need some information. Can anyone please tell me the regulated fuel pressure, the desired voltage from the air mass meter at idle and the injector pulsewidth. Once you have raised the idle to ,say, 2500 rpm the O2 sensor begins switching correctly and exhaust emissions are normal, but at idle the O2 sensor is stuck on 'go lean' and CO% is 10+
I suspect fuel pressure is the culprit at 2.5bar vac connected and 3+bar vac disconnected/under accel.
Thanks Guys
Drew Moorey

Jul 6, 2003 | 01:30 PM

Kevin M

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Posts: 18,369

From: Reno, NV

Car Info: 1993/2000/2001 GF4 mostly red

It's probably simply the matter of the STi motor running big fat injectors for making 300+ hp at high rpms. It can't help but run rich at idle.

Jul 6, 2003 | 10:58 PM

Moorey

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Thanks for your reply. Is this an aftermarket modification? Not an issue at present as the car has a current MOT (Cert of roadworthiness) but will have to have an emissions test in near future and there is no way Subaru could import an engine at this level of fuelling. I suspect from your reply I am going to have to refit original injectors for the test then hope owner doesnt get 'a tug' from the constabulary doing a spot emissions test!
Moorey

Jul 6, 2003 | 11:54 PM

ImprezaRSDriver

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From: Mann Engineering, Santa Clara, CA

Car Info: 13BRZ, 11FXT, 08T25, 07STI, 02WRX

BAN SUVs,

I am not sure if you have noticed but he is from the UK. They do not have the 2.5L engine and are running an EJ20 with top feed injectors and not side feed like the EJ25.

Normally the engine runs a little on the rich side. Even the stock WRXs will run just a tad rich. If you can get someone to data log what the ECU is doing, then you can figure out what is causing the problem.

Jul 7, 2003 | 11:13 PM

Moorey

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Thanks IRSD, As usual customer is starting to give me the whole story and the fuelling issue is recent as it was ok at last emissions test. This is why I need the info asked for. I still think it is excessive fuel pressur.
Moorey