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Paul Workman · 06-27-2012

I went to AutoZone where they'll let you borrow a pressure gauge with a deposit. You decide to keep the gauge, you keep it and they keep the deposit.

I was also able to buy and extension for the gauge from them so I could tape the gauge onto the windshield to monitor FP under driving and WOT conditions.

Doing a static test with the key on, the secondary pump runs, as Scott pointed out, for about 2 seconds - perhaps not long enough to evaluate the FP, especially if the rail is not fully charged. However, that can be easily addressed.

By turning the key off and running a jumper wire from the positive batt post to the fuel pump test connector, both pumps should come on and you should see 52 ± a pound or so. (Note: The pump test connector is black connector attached to a short red wire located in the harness next to the testing/analysis connector (The yellow alligator clip is seen attached to the pump test connectory. FYI, A few early 90s had that connector located behind the battery).

FWIW, if you have a VOM, you can configure it to read current, and determine the current draw. This too will indicate wheter both pumps are drawing the proper current (about 4-5 amperse each for a total of approx 8-10 amperes if both are running normally).

So, with a FP gauge, and a VOM, you can determine a lot about the fuel system's operation in short order!

P.

06-27-2012	#6
Paul Workman Join Date: Nov 2007 Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri Posts: 6,466	Re: Checking fuel pressure I went to AutoZone where they'll let you borrow a pressure gauge with a deposit. You decide to keep the gauge, you keep it and they keep the deposit. I was also able to buy and extension for the gauge from them so I could tape the gauge onto the windshield to monitor FP under driving and WOT conditions. Doing a static test with the key on, the secondary pump runs, as Scott pointed out, for about 2 seconds - perhaps not long enough to evaluate the FP, especially if the rail is not fully charged. However, that can be easily addressed. By turning the key off and running a jumper wire from the positive batt post to the fuel pump test connector, both pumps should come on and you should see 52 ± a pound or so. (Note: The pump test connector is black connector attached to a short red wire located in the harness next to the testing/analysis connector (The yellow alligator clip is seen attached to the pump test connectory. FYI, A few early 90s had that connector located behind the battery). FWIW, if you have a VOM, you can configure it to read current, and determine the current draw. This too will indicate wheter both pumps are drawing the proper current (about 4-5 amperse each for a total of approx 8-10 amperes if both are running normally). So, with a FP gauge, and a VOM, you can determine a lot about the fuel system's operation in short order! P.