ZR-1 Net Registry Forums - View Single Post - '91, Cranks but No Start (and radiator fan runs?!)

Paul Workman · 02-23-2015

If fuel pressure is nil, of course that is an issue. SO! Starting with fuel delivery:

You can see if the pumps are at least drawing the right current by using the diagnostic connector - a red wire with a black connector poking out of the large wire loom, just to center of the ECM.

With the switch OFF, the current draw between the (pos) terminal of the battery and the diagnostic connector should be 4-5 amperes per pump, or 8-10 total with both running.

If in fact you have the proper current draw, you should be able to measure approx 55 psi at the Schrader valve (located at the front end of the passenger-side rail.) If not, the delivery circuit comes under suspicion; starting with the hose connection at the pumps themselves. (not uncommon to have the hose come off, after all these years!)

No need to get into a dissertation on "next steps" now, especially since you have the FSM. The troubleshooting charts will walk you through the rest of the fuel delivery, for the most part. Let's see what develops - would be my approach...

02-23-2015	#4
Paul Workman Join Date: Nov 2007 Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri Posts: 6,466	Re: '91, Cranks but No Start (and radiator fan runs?!) If fuel pressure is nil, of course that is an issue. SO! Starting with fuel delivery: You can see if the pumps are at least drawing the right current by using the diagnostic connector - a red wire with a black connector poking out of the large wire loom, just to center of the ECM. With the switch OFF, the current draw between the (pos) terminal of the battery and the diagnostic connector should be 4-5 amperes per pump, or 8-10 total with both running. If in fact you have the proper current draw, you should be able to measure approx 55 psi at the Schrader valve (located at the front end of the passenger-side rail.) If not, the delivery circuit comes under suspicion; starting with the hose connection at the pumps themselves. (not uncommon to have the hose come off, after all these years!) No need to get into a dissertation on "next steps" now, especially since you have the FSM. The troubleshooting charts will walk you through the rest of the fuel delivery, for the most part. Let's see what develops - would be my approach...