No power to crank fuse
07-27-2015, 07:48 PM
#1
3rd Gear
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No power to crank fuse
fuel problem, fuel pump good, changed fuel filter and before doing so removed 4amp crank fuse to run out gas. Changed filter and reinstalled fuse but fuse has no power. Car cranks but will not start, fuel relay clicks when power supplied. Should I have to just keep cranking for oil pressure to have fuel prime?
07-27-2015, 09:33 PM
#2
What year? I would turn the key from off to on not trying to start should here the pump run for two seconds if so do it a few times then start the car
07-28-2015, 12:17 AM
#3
Race Director
By "crank fuse" I assume from your wording that you mean the "FP" fuse. It only has power on it for 2 seconds when the ignition is first turned on and when the engine is turning. It gets power through the fuel pump relay or the oil pressure switch. The fuel pump relay is turned on by the ECM when it sees reference pulses from the ignition module inside the distributor, which happens when the engine is turning, whether cranking or running.
07-28-2015, 02:09 AM
#4
Race Director
Cliff if its an 84 there is a crank fuse, powered through the starter interrupt relay. If the starter cranks it will have power and provide a crank input to the ECM, if good.. One reason the year from the OP would help..
Last edited by ccrazor; 07-28-2015 at 02:14 AM.
07-29-2015, 01:48 AM
#5
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no power crank fuse
Tried to start by switching key on off several times and can't seem to get oil pressure up past 23psi. Does the fuse with key on have power for 3-4 seconds or should it show power with switch on constant? Car ran before I pulled and replaced same fuse. I have seen similar no fuel pressure when ecu prom was bad. Maybe it was not even the fuel filter to begin with. By the way it is 1985 Corvette. Thanks
Last edited by Mr Kirk; 07-29-2015 at 01:53 AM. Reason: No year
07-30-2015, 09:40 PM
#6
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crank fuse no power
Tried that and after further checking found no power to crank fuse, no power to inst clstr fuse, no power to FP fuse. It is 1985 and I went direct to fuel pump which worked, replaced fp relay and I can hear it click when igniton key turned on. Possible ECM problem?
07-30-2015, 09:45 PM
#7
07-30-2015, 10:40 PM
#8
Race Director
Checking I found that the 85 is similar to the 84 in that there is only power to the crank fuse while the starter is engaged, there is only power to the fuel pump fuse when power is applied through the relay or oil pressure switch.. It almost sounds like you need to check fusible links, with other circuits without power..
07-30-2015, 10:49 PM
#9
Checking I found that the 85 is similar to the 84 in that there is only power to the crank fuse while the starter is engaged, there is only power to the fuel pump fuse when power is applied through the relay or oil pressure switch.. It almost sounds like you need to check fusible links, with other circuits without power..
