I've owned the XJ for a week and a half and haven't had any trouble until tonight. It'll crank in Park and Neutral but won't start. I contacted the PO and he said the NSS is kinda finicky sometimes. I wiggled the shifter and tried everything I read here on the forums with no luck. If the NSS is bad, would it even crank?

The other thing I suspect is the fuel pump. I took the cap of the MPI fuel rail test port and depressed the valve and nothing. No spray, no gas, no pressure. This happened before on my 97 Sierra. Parked the truck after lunch, and after work it wouldn't start. It was the fuel pump and sending unit.

Thoughts?

 

If the starter cranks the NSS isn't the problem. No pressure in the fuel rail on the other hand...that'll keep it from starting. Do you hear the fuel pump run when you turn the key to "on"?

 

crank and no start on a 4.0 first thing i would check is the crank sensor fairly comon to go out on there engines

 

x2 spray startng fluid in throttle body tube if it start get a fuel pump

 

I'm not hearing the fuel pump prime up. Doesn't seem too tough to replace. At least you don't have to drop the tank.

 

CPS.

Check it.

Also, make sure the wires didn't come loose on the ballast resistor. Inside drivers side fender.

 

Ballast resistor is good. The CPS sensor....round plug with 3 pins? My Haynes manual says they're supposed to be labeled A, B and C (but of course they're not). Book says 200 ohm resistance on a hot engine. I got 4.5k ohms on a cold engine. From what I've read, the CPS would cause a poor running condition, which I didn't have. It ran perfect when I parked it.

For the starting fluid trick, where would you spray it in? The air intake to the manifold?

 

I have a 1990 xj and the fuel pump went out a few months ago. If your not hearing it prime when you turn the key into the start position then I would pull the pump out, hook it up to a power source, and test it. I did that and saw that one of the electrical connections came loose from a bump in the road. I reconnected it, soldered it in place, and its still working today. hopefully this helps!

 

Pulled the plug from the connector and got 6.2 volts with the key in the 'run' position. I ordered a new pump even though the PO told me he replaced it 3 years ago.

 

6.2 V at the fuel pump? Check the voltage at both ends of the ballast resistor and let us know what you get. (Or just jumper the resistor out and check the FP plug again)

 

Changed the fuel pump and victory is MINE!!! It actually wasn't too bad except when I got gas in my eyes....that part was bad.

 

w00t!