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Discussion Starter · #1 ·
let me start by saying this truck sat in a field for 5 years. fresh battery, prime all cylinders, compression check, fresh fluids and this is what i can't get right...
no spark or fuel. i thought the ignition module was the problem so i replaced it. no help..
all fuses are good, however i just discovered that i have no power going into the fuel pump relay all reading ground and not changing to hot with the key on. everything else has power. coil, injectors, even the electric fan in the grill will work when jumpered. but i still have no spark and no fuel.(nort even priming) my selector swich has power. im beginning to think ecm
but i have that gut feeling that it is not and that its something much simpler i am over looking. i now its a bunch of jumbled stuff to read, welcome to my brain! but any advise would be greatly appreciated thanks.
 

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ECM cycles the fuel pump for 2 seconds when the key is first turned on.It wont power the fuel pum after that until oil pressure close the oil pressure switch and that runs the pump continuous after that.
Be sure you have power to the coil.
Then Check the pickup coil in the dizzy with an ohm meter. It should be between 300 and 900 IIRC. It should not read infinite or zero is the point.
The pickup coil is the trigger for the ignition and injectors.
Also make sure the dizzy turns when cranking, if its not it wont trigger the system. If it doesnt turn , then its a mechanical internal problem in the engine, like a broken timing chain or stripped dizzy gear (neither one likely but possible)
 

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Discussion Starter · #3 ·
the pumps aren't even priming. and if it will not fire how is it supposed to read oil pressure.. the dizzy u refer to is infact spinning, i will check it with a meter. i replaced the entire distributor because i had suspected that and the ign module. my problem is before that somewhere.
 

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The oil pressure switch at the back of the motor completes the fuel pump circuit after the engine starts.
I understand you have no prime pulse? are you sure you have no Pulse or do you have pulse and no pump action.
Verify the pump is actually getting power back to it, if so the pump is bad, or the connection to the pump has failed.
Check the F pump fuse at the firewall, next to the pump relay, also verify the relay is cycling when the key is turned on.If the fuse is blown, the pump may be bad, or there is a short somewhere. If the relay doesnt cycle, verify it has power at 2 of the relay terminals with the key on, if so check the ground pulse circuit from the ECM.If no ground pulse, it could have an ECM problem.
You did check ALL the fuses ....Right? ECM ECM?BATT etc, all have to be good.

Grey wire back at the tank is the pump power. Check it with a test light , if you get that far.
 

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most vehicles have a fuel pump test wire under the hood. Just supply 12v to it and the pump is suppose to run and it should start. If it doesn't run like that then the pump is bad.
 
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