New fuel pump and relay and no power to pump

Good morning,

First, go over your work with the transmission. I believe there is a ground wire on one of the bell housing bolts at the top. Make sure it is connected and tight.

I attached a wiring diagram for you to view. You will need a test light or voltmeter to do some wiring tests to find the failure.

https://www.2carpros.com/articles/how-to-check-wiring

The gray wire is what goes to the fuel pump. Test that for power when you turn on the key. It will run the pump for 2 seconds and shut off.

Roy

Hello my name is Dave.

First thing I would recommend is to see if you have any codes stored. One thing I suspect when a transmission has been replaced on these vehicles is the oil pressure/fuel pump switch on the back of the engine, I have seen the wires get pinched on reinstall and cause the problem you have described. The switch is right behind the intake on the driver's side, check and make sure those wires didn't get pinched or damaged.

If you can check on those wires and let us know the results we will be glad to assist you further if needed, please keep us up to date on your progress and thank you for using 2CarPros!

I actually had to replace the whole sensor because I noticed when I took the other transmission out it was completely broke.

Did you check the wires at the relay for power?

The oil pressure sensor has no involvement in the fuel pump circuit.

Did you check the ground wires?



Roy

When I hook the test light up to the negative side of the battery and touched parts in where the relay was I do have power going to some part of the relay but as far as anything going past that I have no idea. The thing is is that when I put the transmission in it I had to jump the truck and it started and ran fine for about 3 to 5 minutes at which I forgot time the fuel pump just shut off and stopped working.

Yes, I read that.

Let me know when you can do pinpoint testing and I will walk you through it.

Roy

Not really sure what I would need to do it. All I have is a test light with a 1 foot cord.

You need to go to the relay and remove it. With the key on, you should have 1 terminal that has power.

Then test the other terminals. Have someone in the truck and turn the key to on. 1 of the other terminals should have power for 2 seconds and shut off. That is normal.

Do these checks and let me know.

Roy

Okay. Should the test light be hooked to the negative side of the battery? When it comes to electric and wires I'm a little clueless.

Yes, black lead to the negative side of the battery.

I attached a guide for using the test light for you.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Roy

I was able to hook the test light off. I do have one that comes on when the key is off and then there is one that comes on when the key is turned on and it is a separate one.

Okay, good.

When you turn on the key, can you feel the relay energize and then release?

Roy

I took the relay to work and put them in our work truck which has the same fuel relay and it worked in the work truck.

That is not what we are doing. We are testing voltages, not testing the relay.

Please do the checks I requested.

Roy

Okay. With the negative side hooked up and no key in the ignition or on I have one light where the relay is supposed to be with the test light.

I can also put the relay in and turn the key over and feel the relay click and then click again after a few seconds.

Okay, that is good. That means it is being activated by the ECM.

Now you need to go to the fuel tank and test the gray wire for power when you turn the key to on.

If you have power and the fuel pump does not work, you need a pump.

If you do not have power, then there is a wiring issue between the relay and the fuel pump.

Roy

Okay, does the test light need to be hooked up to the negative side of the battery or can it just be hooked up to a ground on the bottom of the frame?

Just to a good body ground. There are many places to hook it to. Just make sure it is a good clean contact.



Roy

When I put the key in the ignition and turn it on there is no power coming to the gray wire, but there is power going to the purple wire which is the one that is in the middle of the three.

Purple wire is the sender.

Did you have someone else turn the key while you monitored the test light? It will only have power for 2 seconds.

Roy

Not at the moment I did not. I did however crop the top slide into the gray wire connector and then turn my camera on darn record with me going up putting the key to the on position then off then on again then off and then whatever checked the video and didn't notice anything. But it could not have been and they're all the way and that's something that I can do in the morning with the neighbor and let you know as soon as possible.

Sounds good.

Keep me updated.

Roy

So I just got off work and got back to the house and was able to have someone put the key in the ignition and turn it over and when they turned it over the test light hooked up to the gray wire did light up for about 2 seconds and then went off.

Okay, if the pump does not work, then make sure the ground is good. If it is, then you have a dead pump and needs to be replaced.

If the pump does run, then I would check the pressure. It could still be a bad pump.

Roy

The pump does not come on at all. is there a way to take the pump out of the tank and test the wires going into the tank to make sure that the power going all the way down to the pump?

You would need to drop the tank and remove the pump.The tank has to come down to gain access to the pump.

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

Roy

Right now it's getting a little cold and dark outside. So tomorrow when I get off work I'm going to drop the fuel tank out but there is a black and a red wire that go to the actual pump itself. Should I just have the test light held to a good ground and to the red wire to see if it's getting power to where the pump should connect?

Because I would like to make sure that the actual sending unit is in good working order because as long as the sending unit is in good working order I should just be able to replace the actual pump itself correct?

That is correct.

The gray and black are the fuel pump wires and the purple and black are the sender wires.

Roy