Cranks, but no Start - help please
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From: sw mich
Cranks, but no Start - help please
Hey all,
I'm trying to diagnose a no start issue on my son's 1997 F150 4.6L W code motor. It quit on him while driving and we haven't been able to get it re-started since.
We immediately assumed the fuel pump was bad as we were not getting any fuel pressure and we cannot hear the pump running at key on. So we pulled the pump and bench tested it, and the pump itself seems fine.
We then checked for spark, we have spark in all cylinders. After that we started checking fuses and #30 was blown. We replaced that and it blew again at Key on. We ended up going through about a 1/2 dozen of them while poking and prodding at misc. wire harnesses trying to figure out why it keeps blowing. Today we put a new one in and have tried restarting and that one is not blowing anymore, but we still cannot get fuel pressure.
We've checked all fuses and swapped relays around.
We noticed 20 and 21 do not have power, but the fuses are ok. Are we finally on to something here?
Any other ideas?
Thanks,
Mike
I'm trying to diagnose a no start issue on my son's 1997 F150 4.6L W code motor. It quit on him while driving and we haven't been able to get it re-started since.
We immediately assumed the fuel pump was bad as we were not getting any fuel pressure and we cannot hear the pump running at key on. So we pulled the pump and bench tested it, and the pump itself seems fine.
We then checked for spark, we have spark in all cylinders. After that we started checking fuses and #30 was blown. We replaced that and it blew again at Key on. We ended up going through about a 1/2 dozen of them while poking and prodding at misc. wire harnesses trying to figure out why it keeps blowing. Today we put a new one in and have tried restarting and that one is not blowing anymore, but we still cannot get fuel pressure.
We've checked all fuses and swapped relays around.
We noticed 20 and 21 do not have power, but the fuses are ok. Are we finally on to something here?
Any other ideas?
Thanks,
Mike
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Joined: Jan 2004
Posts: 19,762
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From: St Louis
If F30 is blown, you cannot have spark since F30 supplies, among other things, the coils. You will also have no fuel pump since F30 has to supply power to energize the PCM Power Relay which supplies power to the PCM which then issues the command to run the fuel pump by energizing the fuel pump relay.
You should find plenty of of info regarding F30 in these threads:
Ford Truck Enthusiasts Forums - Search Results
Ford Truck Enthusiasts Forums - Search Results
Which fuse box, there are two with those fuse designators in each?
You should find plenty of of info regarding F30 in these threads:
Ford Truck Enthusiasts Forums - Search Results
Ford Truck Enthusiasts Forums - Search Results
We noticed 20 and 21 do not have power, but the fuses are ok. Are we finally on to something here?
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Senior User
Joined: Dec 2004
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From: sw mich
The fuses I referenced are all under-dash fuses. The fuses in the power distribution box seem to be ok.
So far #30 is holding up. I've got a fuel pressure gauge hooked up now, but can't seem to get the fuel pump to energize. We've swapped the fuel pump relay and even bought a new one for it. We also pushed the button on the inertia switch.
I'm not sure if this is related, but before it quit we had been dealing with some rough running and misfire issues. We've changed plugs, wires, and both coil packs. The plugs needed to be changed pretty bad, but changing them didn't help much. We haven't gotten the back plug on the passenger side yet though - we're still trying to figure out how to get the crud out of the hole still. I think something is going on with the PCM circuit, just don't know what to look for.
Also, thank you for the links to some search results, but I couldn't get them to work.
So far #30 is holding up. I've got a fuel pressure gauge hooked up now, but can't seem to get the fuel pump to energize. We've swapped the fuel pump relay and even bought a new one for it. We also pushed the button on the inertia switch.
I'm not sure if this is related, but before it quit we had been dealing with some rough running and misfire issues. We've changed plugs, wires, and both coil packs. The plugs needed to be changed pretty bad, but changing them didn't help much. We haven't gotten the back plug on the passenger side yet though - we're still trying to figure out how to get the crud out of the hole still. I think something is going on with the PCM circuit, just don't know what to look for.
Also, thank you for the links to some search results, but I couldn't get them to work.
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