zombiexj

I keep loosing my prime of fuel. In the morning or after work I crank it and it pops then it dies and I have to wait on fuel pump or crank for a bit. Is there a check valve if so where is it. I have a 90 xj renix fuel system. Thanks.

Radi

Yeah, there's a check valve. I don't know where it is on the Renix, later models it's part of the pump assembly, I'd guess Renix is similar, but I"m guessing.
You can get around the problem by turning the key to ON a couple of times to let the pump run and build pressure back up.

DFlintstone

Yea, the check valve is in outlet. This is the 87-90 pump. The darn pin that drives the impeller gave it up...ran fine though. Stranded me in the rain..of course.

cruiser54

Yes. The "poor man's prime" will verify if this is the problem.

Oddly enough I had this happening on my Comanche. Did the fuel pressure test and a fuel pump test from the FSM. After that no more issues. I wonder if some crap gets in the check valves.

DFlintstone

Sure seems possible. Mine "got better" as well.....but there was some injector swapping going on. (a leaking injector could let the pressure drop too).

I wonder if a guy could cap off the fuel line, let the pressure build as high as it will, then suddenly let it go to maybe dislodge something in the check valve. Of course if it won't fit out....it won't get out.

95Cherokee

95Cherokee

This is just me but I don't have the ***** to chop my metal fuel line and insert and rubber hose, seems like you're just asking for trouble.

Pelican

I don't know about a '90, but on a '93 it is easy to instal an aftermarket check valve in the rubber line behind the fuel filter, no messing with the metal line. I got the valve for $17 off eBay 4 years ago. Holds full pressure at least 3 days -- no waiting for prime, just turn key and start.

cruiser54

There's already rubber hose back there under pressure.