A while back I posted about problems with an 01 PPP + full decat being down on power. At the time I suspected with few others that a dodgy ECU was at fault. Today I run another PPP ECU, that is known to be okay, against mine in the same car. Both ECU's produced the same power give or take 2-3 horses.

The problem is being caused by the car over fuelling like a barsteward. The only problem is there are no ECU error codes and no apparent air leaks anywhere.

On the first run today the car produced approx 240bhp and 230 lbs/ft torque. On checking the exhaust gas analyzer you can see the fuelling goes to +10% and then goes off the scale never to come back down.

We fitted an HKS AFR to see what would happen and power went from 240 to 270 bhp in one hit, torque went up from 230 to 250 lbs/ft.

The only problem is the HKS AFR is set to maximum yet the car stil over fuels by a ridiculous amount, it still goes to over +10 % and never comes back down.

I need to try and sort out what the underlying cause of the over fuelling is. Any suggestions about what could be casuing it would be greatfully appreciated, this is really starting to get me down now and is costing a small fortune.

Thanks

Nathan..

 

Below is the comparitive power run with and without the AFR.



A lot better and smoother but still room for improvement.

Nathan..

 

Anybody ?

 

Most Subarus are well over 10% CO - off the scale on many analysers/AFRs. Sorry no other suggestions unless you check the MAF readings are sensible, but I have not so far heard of an over-reading MAF. Just another thought - what is the fuel pressure - is the regulator doing dodgy things? Also by running the car on something like Delta Dash or a Select Monitor (presume they did if you were at PE?) then you would be able to compare the MAF signal and injector pulse widths with other cars?

 

when a lambda probe is failing do they not throw in extra fuel?

 

John

Thanks for the reply, I see what you mean. We did compare it with other PPP'd cars on delta dash and it seemed to be okay. The other PPP'd cars all stuck around + 8-9% on the CO analyser. Even with the AFR fitted to maximum lean out it still goes off the scale.

I have the Delta Dash logs if you could make sense of them, I know a bit but I'm no expert.

I think the way forward is to swap some sensors with another 01 and see what happens. Having spoken to a couple of people apparently the MAF sensor on the 01 can be erratic especially on earlier cars.

T-UK
Thanks for the suggestion, will try that sensor too.

Thanks

Nathan..