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Re: What a FPR issue ARI? Posted by Ari [Email] ![]() ![]() In Reply to: What a FPR issue ARI?, James, Sun, 26 Oct 2008 01:51:18 Members do not see ads below this line. - Help Keep This Site Online - Signup |
I checked back, and you were running base boost. The possibility was that the BPC valve was stuck. Another possibility was that the engine really was knocking, and the APC was dialing back the boost.
One reason why an engine could knock would be if it were running lean. And the FPR - Fuel Pressure Regulator - could be a reason. The FPR adjusts the fuel pressure to keep the pressure drop across the fuel injectors constant. So at high vacuum (idle, closed throttle), the fuel pressure is low. As the boost increases, the fuel pressure increases.
If the FPR is bad, and the fuel pressure isn't increasing, then the engine will be running lean under boost. Running lean can cause knock.
Check the plugs - do they look good, or do they look lean (or rich)?
posted by 75.25.4...
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