90 XJ - Starts but wont stay lit!!

I have a 90 XJ 4.0 with aw4 tranny. It will start but quits after a couple of seconds. Upon trying it a couple dozen times, it will eventually keep running. A couple of times it has just quit going down the road:wierd:

I believe it may be the NSS or the Ignition switch. The reason I am leaning towards the NSS is the fact that it has started immediately after I messed with the shifter. This morning it didn't start on one try and I pounded on the shifter and it started next try.

I just found a link on cleaning the neutral safety switch. Does anyone have any insight as to what the actual problem may be? Has anyone else had this problem that cleaning or replacing the NSS has fixed?

Thanks for your help...this is my daily driver!

Chris

Its not the NSS...if it was it would not crank over... Look for loose or missing vaccumm hoses, especially around the map sensor, it honestly could be a bunch of different things. By you stating that it starts and runs for a bit, tells me that you have fuel and spark upon start up. Instead of pounding on the shifter, place it into nuetral to see if it still starts... best of luck on solving this issue...

:wave: I fixed it!!! It was the ceramic resistor on the drivers side fender that loweres the voltage to the fuel pump. I unpluged it, jumpered the wires, and it starts every time!!

I guess I won't be needing to relpace the NSS after all. I just saved $275.00 with a 1 cent piece of wire.

Sua Sponte :us:

I was gonna guess ballast resistor, but you beat me to it. You HAVE to replace that ballast resistor.

JOhn

Technically you don't HAVE to replace the resistor, but not replacing it may shorten the pump life a bit and will definately make the fuel pump louder. The original reason for adding the resistor was due to noise complaints. Some years do not have the resistor.

old_man said:

Technically you don't HAVE to replace the resistor, but not replacing it may shorten the pump life a bit and will definately make the fuel pump louder. The original reason for adding the resistor was due to noise complaints. Some years do not have the resistor.

Click to expand...

'87, to be precise. The ballast resistor was a running change incorporated late in the 1987 model year. My '87 MJ doesn't have it.