02 TJ 4.0 Fuel Pump Not Working

[TJ Deuce]

Hi!

So I have a 2002 TJ 4.0 automatic with 150k It was sitting for about 2 weeks and wanted to go to the hills. It wont fire up it will crank over but not start. noticed the fuel gage isn't working now also but it had 3/4 of a tank. So I checked spark and I have spark so I checked fuel and I have no fuel to the rail. Checked fuses and fuel module all was good there. I thought ok no problem I will just change the fuel pump. So I changed the fuel pump yesterday and still no fuel to engine. I saw some posts about wiring but I'm in california and the jeep has no rust. I am very bad at wiring so figured it was time to reach out and ask for some advice. I have a Bear tag to fill still. LOL

Thanks in advance!
James

 

[D M]

Since replacing the fuel pump, do you now have pressure at the fuel rail?

 

[Kon]

Did you also change the fuel filter/regulator that sits on top of the tank along with the pump?

 

[macleanflood]

I'm blaming the mice.

Time to check your wiring.

-Mac

 

[TJ Deuce]

Since replacing the fuel pump, do you now have pressure at the fuel rail?

No Pressure to rail still. The new pump did have a new filter included. And Mac where do I start with wiring?

 

[macleanflood]

I'd start with the Factory Service Manual available for your year in the resources section. 8w has the wiring diagram.

You're going to disconnect the fuel pump assembly connector above the rear axle and either using a power probe or whatever you use directly feed 12v and ground to the appropriate pins and see if the pump turns on...you'll hear it...and you get 49 ish psi to the rail.

That'll tell you if the pump runs.

Then you can hook up a volt meter to the plug running down the chassis to the appropriate pins and see if you get 12v when the Jeep key is rolled to the on position. It may only be a brief run of power...2-3 seconds.

We're trying to determine if the problem is the new pump assembly or the Jeep.

-Mac

 

[TJ Deuce]

HI Mac! So I got power to the pump and got 50psi at the fuel rail but even putting direct power to the pump and I can hear and see with fuel pressure gage the damn thing still wont start.

 

[macleanflood]

Will it start if you spray carb cleaner or starting fluid into the throttle body?

Wondering if you need to get some noid lights to see if your injectors are pulsing.

-Mac

 

[TJ Deuce]

Maybe but there is still no power to the fuel pump but pump did work when I put power to it. I was also suggested to jump the fuel pump relay so it would eliminate possible bad ground or broken wires so I did and it sent power to the fuel pump.

 

[macleanflood]

Gotcha. Misunderstood your post. When you said you had power to the pump I assumed it was from the Jeep.

I'd suggest looking at the factory service manual and following the ASD relay troubleshooting procedure.

-Mac