Fuel pump run without memcal?

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Feb 17, 2011 | 11:39 PM

jeff355

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From: Belle River Ontario

Fuel pump run without memcal?

Does anyone know if the fuel pump will run at all without the prom chip in? Im troubleshooting the cars wiring, while the chips away getting reprogrammed and the fuel pump is not priming. Any help would be great.

Feb 18, 2011 | 12:46 AM

rodj

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From: Australia

Doubt it
Once the memcal is gone there is no programming left ; not even limp home mode

There are ways to make the fuel pump run independent of the ECM for testing purposes

Feb 19, 2011 | 04:41 PM

jeff355

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From: Belle River Ontario

Like how? Paper clip in what adl hles

Feb 19, 2011 | 06:47 PM

rodj

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From: Australia

Quote:

Originally Posted by jeff355

Like how?

12V to terminal G on ALDL connector ( assumes FP relay is functional )
jumper OP switch on block
jumper Fuel pump relay

Feb 19, 2011 | 09:19 PM

JackDidley

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From: Database Error Indiana

FP can get power from the oil pressure switch. I dont think the ecm controls that at all ???

Feb 25, 2011 | 08:34 PM

Kubs

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Quote:

Originally Posted by JackDidley

FP can get power from the oil pressure switch. I dont think the ecm controls that at all ???

The ECM controls the fuel pump priming and cranking. Once the oil pressure switch gets oil pressure it energizes the relay and the pump runs off the op switch then. The chip is still needed for priming and start.

Feb 25, 2011 | 09:10 PM

JackDidley

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From: Database Error Indiana

I think the switch can get enough pressure to turn on the pump, just cranking it over. If I wasnt such a slacker, I'd go pull the chip, hook up the pressure gage and try it. Chip is on the dash so it wouldnt be hard.

Feb 25, 2011 | 09:35 PM

rodj

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From: Australia

Quote:

Originally Posted by JackDidley

just cranking it over.If I wasnt such a slacker, I'd go pull the chip, hook up the pressure gage and try it.

No need to ;
it will work as you say because it is a independent mechanical switch

But
it means you have to keep cranking engine over to maintain OP to close the switch while testing pump wiring
whereas putting 12 V to ALDL pump terminal or jumpering the OP switch terminals will make the pump run
with the key off

Last edited by rodj; Feb 25, 2011 at 09:41 PM.