Tuning with new fuel pump?

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May 13, 2006 | 06:20 PM

brians98ss

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Tuning with new fuel pump?

Hi guys,

I've been getting some conflicting information concerning this topic. Do I have to re-tune the PCM due to the installation of a new fuel pump? I didn't think so but I have been told otherwise.

Any comments?

Thanks,
Brian

May 13, 2006 | 07:57 PM

onfire

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From: Virginia

Unless you tuned on a really bad pump before you installed the new pump, NO.

May 13, 2006 | 09:52 PM

RedHardSupra

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From: Laurel, MD

if your fuel pressure changes, then you're effectively altering the injector flow, so IFR needs to be adjusted. look in the stickies for a spreadsheet, you can plug in some numbers and see it for yourself.

May 14, 2006 | 03:58 PM

brians98ss

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Quote:

Originally Posted by RedHardSupra

So it sounds like I need to take fuel pressure readings at the fuel rails to determine if there is a pressure difference before and after the pump install.

Since I'm keeping the stock fuel pressure regulator, is it correct to say that I should see approximately the same pressure before and after?

Brian

May 14, 2006 | 06:59 PM

RedHardSupra

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it can be correct. but every car i tune i measure the fuel pressure gauge, just to make sure it's correct. IFR settings are way too important to just leave it to chance/imprecision.