Okay so frustration has set in. 96 XJ with 4.0 and 65k original miles. Owned for two years and it’s been hard starting since I bought it. At the Schroeder valve when I turn the key on without starting my fuel pressure gauge reads 20 psi for a split second and than drops to 0 psi. When I cycle the key to get it started it runs at about 30 psi. When sitting for the night the next morning I have to cycle the key and than it starts after a few seconds but runs rough for about 7-10 seconds and smooths out and drives great after. I have replaced the injectors and just tonight I replaced the fuel pump and filter. Has No leaks....Suggestions?

 

Check out this thread I found. Hopefully you can try some of the stuff here.

https://www.cherokeeforum.com/f2/hav...-start-134759/

 

Thanks I’ll check this out. It’s just that I’ve also replaced all 6 injectors also 🙄

 

if you are getting 20psi then drops to 0 on a new fuel pump? you need a new check valve generally replace both at the same time it should be 49 at the rail and not drop so fast

 

It could be the regulator, which is together in the tank with the fuel pump itself on my '96s..did you replace the whole assembly or just the pump ?
The pump and regulator as individual parts are the same as a '95


what part is the check valve on a '96 ?..is it separate to the regulator ?

 

Is the in tank pressure regulator serviceable? It looks to be in cased into the pump assembly. Also does the 96 model just have the check valve in the pump itself?

 

sorry homebrew I meant on a 96 as awg said the fuel pump and fuel pressure regulator check valve are together in the unit that goes inside your tank you can replace the pump without even realizing that the check valve even existed

 

Have you checked the fuel pressure at the rail? With 65k I’m betting the pump is still good. Is the filter a separate unit?

 

If you've checked or replaced this and I missed it... then forgive me... but correct me if I'm wrong, but on the 96 isn't the fuel filter along the rail just about even with the driver's seat under the jeep? I replaced one on a 97 and it was in that location.
If you're checking everything else, might as well check that too. They are cheap and if partially clogged, would definitely cause problems. With a set of hose clamps takes like 10 mins to swap a new one in.

 

Yes...their is a thread on NAXJA about '96 fuel pumps, and how to do things

I think you can buy a Crown brand entire '96 assembly, but it will probably be a bit expensive

the regulator can be changed out, same part num as the 39psi pre 96 regualtor, just has no vacuum hose, so gives 49psi

I would certainly change the fuel filter, under the floor, and also their is a "sock" on the fuel pump itself...this needs to be clean.

I replaced just the fuel pump itself, with a '95 unit, came with a new sock

my spare '96 has the fuel level sender not working...also built into the assembly...just finding time to fix things...

 

Thanks! I’ll check that out, yeah the fuel filter is newer too but I’ll change it again they are cheap enough. I Put a new sock on also with the new pump. I’ll try a new regulator. I’m hoping it’s that. The injectors maybe have 1500 miles on them and I wouldn’t think they leak into the cylinder but how the fuel pressure goes from 20 to 0 after a second of priming with the key maybe I do have a bad one 😬