zombiexj

I have a 90 4.0 xj renix fuel system. It will fire up ad die right away. I would do this occasionally but start up on second try. Now it just fires off but wont run every time When I cycle key fuel pump runs for 3-5 seconds. Could it be a TPS, check valve, pressure regulator?

RTorrez1

First thing you need to do is verify that you are or are not getting fuel to the fuel rail. You need to get yourself a mechanical pressure gauge and connect it to the fuel rail. I'm not 100% sure but I think that your year the pressure should be at 35psi and it should hold at the pressure. That would be the first thing to check. Check that out and let us know what happens and if you still have problems we can go from there.

cruiser54

What he said. But it's about 31 PSI with the vacuum line hooked to the regulator and 39 PSI when unplugged.

Look on the driver's side fender for the fuel pump ballast resistor. You can jumper across that and see if the problem goes away. Do you own a voltmeter?