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Old 02-07-2002, 02:09 PM   #2
Scooby Newbie
Member#: 12012
Join Date: Nov 2001
Default Re: Questions about my ECM on Warrenty?

Originally posted by Erik Dahlen
I just took my MY02 WRX in on warrenty now here is the problem. The dealer told me that the #3 cylinder was misfiring because there was not enough fuel burning off due to poor oxygen consumption. The dealer sent in the ECM to get it remaped so there would be a widerwindow for the spark plugs to fire. He said the problem was due to the fuel I was using. I live at high altitude in Denver CO and he said that Federal Law requires the fuel have a higher alcohole content for enviromental purposes than in Japan and OZ.

Have you heard anything about this Federal law?

I was using Premium UnL should I continue to use Premium or go to a lower grade? (I think I should the higher grade for the Turbo)

I was also wondering if I should use Synthetic oil or continue to use the 5-w30 SEA?

Is there any brands of gas sold like Conoco that I should avoid besides generic?

Confused and need some answers!!!


Erik, despite my reputation here (ahem) I think I can give you some help.
The remapping of the ECU is done to correct a fuel delivery problem that may develop due to heat from the turbo after a hot soak situation. I know of no Fed law requiring higher alcohol content in fuel in your area, but some fuels do use higher blends of alcohol, especially in the premium octane blends. Your dealer should be able to perform a quick check on a sample of your fuel to determine approximate alcohol content. Anything greater than 10 percent is not recommended by Subaru, and may cause driveability problems. More important than alcohol content is the RVP (Reid Vapor Pressure) of the fuel. If you are using a fuel with a very high RVP, it will tend to vaporize in the fuel line and injector (especially #3 injector, closest to the turbo) when the car is shut off hot. This means #3 cylinder runs lean on hot restart, setting the misfire code. If your fuel is okay, the remapping should take care of your problem.
Hope this helps.
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