low or loss of power to fuel pump

[constrosity]

98 csvt 3.0 swap
Did the swap with a remote battery
Stater turns over, air, spark, but fuel pump has little to no power? Has slight spikes in fuel pump but very low.
Was wondering if from bad tune or maybe grounding problems.
Any help appreciated ☺

 

[crewchiefpro]

Are you saying the car will turn over but there is no power going to the pump? Not understanding what the "swap with remote battery" line means.

Usually no power means wiring or fuse to ECU is blown.

 

[gmorrell]

Per Occam's razor, these are in order of most obvious to least obvious.

Does the fuel pump cycle on briefly (about 3 seconds) at Key-on?

Check the fuel pump fuse. Pull the fuel pump relay in the underhood fuse box and jumper the contacts. Does the pump run?

Got a voltmeter? While the relay is out, make sure one side of the fuel pump relay coil connections goes low as commanded by the ECU. The other side of the coil is connected to Vbatt.

Under cranking, the pump won't re-start unless the ECU sees the crank sensor. Crank sensor OK?

Did you upgrade the fuel pump to a higher capacity unit? The additional current draw from larger pumps is know to over-stress and burn the contacts in the fuel pump module connector.

 

[constrosity]

Just put in a new crank sensor , the remote battery (mounted battery in trunk and run lines to it), checked the pump and doesnt seem to turn on at all even at first turn of key, used voltmeter key-on and after crank still low power, and yes everything else has power from what i can tell just the pump and I believe a few other sensors are showing power loss. Thats why I was wondering if it was a grounding issue, if that, any one have an idea where to check? Again thanks for your help!

 

[amc49]

You need full power at the pump regardless of the ground condition, it just won't run until properly grounded, should have power at key on though. The ground only completes the circuit after power gets to it.

Or you need to make up your mind as to the true issue, you are mixing the two halves up of any electrical circuit.

I'd be double checking your PCM ground condition too. As well any grounds since you DID remote the battery. Since YOU did the work really no way we can now tell you exactly where to look, you have changed the system up enough to no longer be able to do that. Self-inflicted damage there and why your work has to be dead reliable since you now are the only one knowing what you did.

 

[BrApple]

was the battery just relocated or has it been done for awhile?

 

[gorman]

Just put in a new crank sensor , the remote battery (mounted battery in trunk and run lines to it),!

Try putting the old crank sensor back in .... if it starts, check you have over 14v at the battery to eliminate any poor battery commection issues.


You could try checking the three large connectors down the side of the rear valve cover .... they need to be properly seated. I have zip ties holding mine securely after similar symptoms ....G.

 

[constrosity]

Ill check the grounding on the remote battery and the back valve and the remote job was done during engine swap to make room for electric/remote water pump. Had a taurus engine without the pulley driven pump. Its been an ordeal to say the least, lol.