farmfuel

Hi to all,

The other day, I went out to fire up the XJ, and it wouldn't start. It ran fine the night before. In doing some testing, I noticed that there was no spark to the plugs. The fuel pump fires up, so I know the computer is enegerizing the fuel pump relay. My first experiment was to replace the CPS with a unit that I got off my old motor. I'm not 100% sure if it works or not. After that, there's still no fire. I did the same thing with the coil; I swapped it out with the coil from my old motor. I wasn't able to do a resistance test on the coils, because my multimeter is puking out. After I swapped out the coil; still nothing. Last Saturday, I went out to the junkyard and got a computer. Still no luck. At this point, I'm getting kinda frustrated. I pulled the cap off the distrubuitor to see if the rotor was spinning. When I did, I noticed part of the magnet for the pick-up had broken off of its plastic base. I was happy to see this, and told myself "its been the distrubuitor all along". So I got an overhauled distrubuitor from the parts house. IT STILL WON'T START! ARGH!!! The auto shutdown relay clicks when you turn the key on, so I know the computer is getting power. There is no current running to the coil pigtail, so the coil isn't receiving 12V when the key is on. I also hooked my noid light up to the #1 injector, and it isn't pulsing; no power to the injectors. I really need a troubleshooting tree, but I don't know anyone who has Alldata, or Mitchell OnDemand, etc.

Can you think of anything else that it might be? I'm going to buy a new CPS today to put on, but I doubt that will fix it. All of the fuses are good, and have power running to them from the buss. Thanks for your help

elpotro1331

had a problem that the jeep would not start but had no fuel pressure switched the relay from ignition and wala jeep lighted up it ended up being the relay dont know if that can help u some

farmfuel

Yea, I've got fuel pressure; when the pump comes on, you can hear the fuel rail pressurize. My problem is no spark; no power to the coil. I even put 12V to the + side of the coil...still nothing.

RENIXBEAST

The last time mine wouldn't start it was the ballist resistor. Its the small ceramic part with two wires connected to it. I would check that, they are cheap an often crap out.

farmfuel

I'm pretty sure that ballast resistor is part of the fuel pump circuit. If you disconnect it, it will kill current running to the FP relay. I'll check it out; thanks for the idea. I want to say that I messed with that thing years ago, and remember it being part of the FP circuit. I'll try it again though.

There was a time on older cars, that the coil did have a resistor running to the + side, because a solid 12V would fry it; older coils ran something like 7V; that's where the resistor came into play. Newer vehicles w/ EFI don't run that resistor to the coil; they take a solid 12V

farmfuel

This is a bump; I really need to get this thing fixed. Does anyone have a troubleshooting tree for a no start condition?

tj40

cps all day!