masteroak

I tried really hard not to post another fuel pump question but decided I would prior to replacing the fuel pump:

'96 Country 4.0L
Replaced the + and - battery cables last week because of no start/no crank issues. Newer battery tests fine and replacing the cables made a huge difference. It was starting in cold temps no problem. Went out the other morning and engine would crank fine but would not start.

Battery is fully charged, good spark, relays and fuses are all good. rechecked cables and all are good. Removed boot and sprayed starter fluid in intake with no hint of firing. Fuel pump does not prime even when ignition is turned to on position. Everything else works fine on the vehicle. NSS test ok. Is this a clear cut case of bad fuel pump?

Is there anything else I should test prior to replacing the pump? The strange thing to me is that I thought it would fire if I sprayed fluid into the intake while cranking but it did not so am wondering if there is something else electrical I am missing.
Thanks for the help!

RTorrez1

If you sprayed starting fluid and got no hint of it starting you may want to check you CPS. At least that is what I would check next.

SeriousOffroad

Bypass the FP Relay and apply 12vDC directly to the pump.

Fsher21

If your issue was fuel related, there is a good chance it WOULD of started with the starting fluid like you thought. X2 on the cps, there are some nice write ups on how to test that around here if you search.

masteroak

Thanks,
I will test CPS and report back. Need to get my service manual back from a friend today. Tried disconnecting the fuel pump wiring harness but am afraid I am going to break it since I can't figure it out. any advice on that so I can check the fuel pump itself? Will need to do this anyway if I have to replace the fuel pump.

SeriousOffroad

See post #3

masteroak

Will do as soon as I am smart enough to figure out how to unplug the fuel pump without breaking the connector. Unless there is another way to do it from the engine compartment that I am unaware of.

SeriousOffroad

https://www.cherokeeforum.com/f5/fue...coming-117708/

masteroak

Much appreciated. No sound from fuel pump at all....confirms bad FP right?

SeriousOffroad

Electrical troubleshooting 101;
(Assuming the wiring and connectors are good)
When a known voltage is applied to a load and the load fails to operate then the load is bad.

Let me know if you need a new fuel pump assy. I know a guy....

masteroak

pm sent and checking out the web site now....

freegdr

if you sprayed starting fluid and it did not try to start you have a nother issue jm2cw

Zack92MJ

Starter fluid makes mine harder to start?

masteroak

OK tested the CPS also. Got a reading of 752 from b to c and 1852 form a to b. This is ok right?
Also last test is direct power to fuel pump. disconnected the pump wiring harness and need to know which pins to apply the power to. red and black? There are so many different posts and thoughts I just want to be sure before I replace the fuel pump.

masteroak

Fuel pump replaced and jeep is running like a champ again. Replaced with a Bosch and it was a piece of cake. Unable to find the whole assembly in town so just swapped the pump into the rest of the unit. Replaced the fuel line and filter while I was at it.

Thanks the help everyone! On to the next issue....