!998 cab and chassis dually small block VORTEc automatic, has no pwer to the fuel pump relay. Truck quit while driving and a crank position sensor fixed it initially then it happened again. Replaced CPS again and do not get any power to the fuel relay block. A shop towed the truck in and replaced the forward fuel pump which I had replaced 3 months prior and still would not start. They ran a hot wire from the tailights and twisted all the pump wires together and the truck runs. Attempting to restore back to factory and now will not run. fUEL GAUGE IS PEGGED HIGH AND HAS NOT BEEN WORKING WITH THEIR FIX, HAD TO TURN ON THE LIGHTS TO START. cOST ME $1000. I need help finding out why the ignition system is not getting power, the pump runs. Its a mess and I am not an electrician much.
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No ignition and fuel relay not getting power
- Thread starter JJR
- Start date
dbrannon79
I'm getting there!
Welcome @JJR
your truck should be turning the fuel pump on for 3 seconds when you turn the key on to run before cranking. check all of your fuses in the under hood and in dash boxes. do you have a scanner to connect to the ECM? verify you can communicate with the ECM. it sounds like ether a fuse to the ECM is blown, or there is a sensor on the engine that has shorted the 5v reference voltage from the ECM.
one other thing to check. pull the fuel pump relay from the socket and probe each of the 4 contacts in the socket with a 12v test light. one pin should have power at all times even with the key off. if nothing, again check fuses, you have lost power from somewhere.
your truck should be turning the fuel pump on for 3 seconds when you turn the key on to run before cranking. check all of your fuses in the under hood and in dash boxes. do you have a scanner to connect to the ECM? verify you can communicate with the ECM. it sounds like ether a fuse to the ECM is blown, or there is a sensor on the engine that has shorted the 5v reference voltage from the ECM.
one other thing to check. pull the fuel pump relay from the socket and probe each of the 4 contacts in the socket with a 12v test light. one pin should have power at all times even with the key off. if nothing, again check fuses, you have lost power from somewhere.
MrMarty51
Well-Known Member
First thing to do is untwist all them wires and make sure that there is nothing on the harness side touching another wire or a ground source.
You are going to need a wire schematic to sort this out and put it all back together as it should be.
IIRC there is two fuses that might be marked ECM1 and another ECM2. Either one of those could be supplying power to the FP relay.
After You get the harnesses restored then follow through with what @dbrannon79 is saying.
These systems are not complicated to dont be intimidated by not being an electrician.
You are going to need a wire schematic to sort this out and put it all back together as it should be.
IIRC there is two fuses that might be marked ECM1 and another ECM2. Either one of those could be supplying power to the FP relay.
After You get the harnesses restored then follow through with what @dbrannon79 is saying.
These systems are not complicated to dont be intimidated by not being an electrician.
MrMarty51
Well-Known Member
Oh yes J, welcome to the forum.
A lot of help in here.
A lot of help in here.
There is no power to the relay pins. I can not find a diagram that shows where the power comes from. The garage connected all the pump wires to my tailight power and had to turn on the lights to start. I did all suggested cheks and have nothing. Only powered the front pump. Replaced all parts, Relays, balance module etc.
dbrannon79
I'm getting there!
Start checking fuses and see what has power and doesn't if the pump relay has no power, there are other things that also out.
MrMarty51
Well-Known Member
IDK about this truck but my old OBD1 truck had two fuses, one marked ECM1 and the other was ECM2.
If either one of those fuses would burn out then there would be no power to the FP relay.
If either one of those fuses would burn out then there would be no power to the FP relay.
dbrannon79
I'm getting there!
dbrannon79
I'm getting there!
Here is links to service manuals for your rig. this might help you with diagrams.
www.dieselplace.com
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BigDogYJ
Well-Known Member
This might get you started.... It's for a 98 K3500 5.7L dual tank rig.
dbrannon79
I'm getting there!
Something I didn't see on the diagram and not sure if they installed them is a fuel cut out switch. it's a switch that will cut power to the fuel pumps in the event of an accident or rollover.
Thanks, found a mouse chewed wire and back in business. Appreciate the help.
Will L.
Well-Known Member
Just like Jinx the cat “I hate them meeces to pieces!!
dbrannon79
I'm getting there!
Glad you found it! meeces can wreck havoc on things.