Need advice on wifes TJ

[Dadinator]

Know not mj issue, but scratching my head.

wifes TJ has been fine until last week. 2.5 5sp 1997.

When she got off work it would not start. Gas gauge shows E.

she said there was gas in it. I Put 2 more gals in it anyway to be sure.

Turns over no fire. Fuel pump does not seem to come on. Swapped fuel pump relay. No good.

 

Did some searching and found a couple of threads that suggesred cps or ecu. Something about a 5v output from ecu will cause these symptoms. Another thread suggested a shorted cps will cause this. Pull the wires from cps and if gauge comes back the probable ecu.

 

Well did that. No go. Ordered an ecu and has the same symptoms. Oddly enough, when i plug in the ecu and turn the key on, the gauge will work for a few seconds and then go back to not working. Only the first time after hooking up the ecu. It does that with both ecus.

 

No start. No gas gauge. Any ideas? Anyone run into this before?

[HOrnbrod]

Did you check for fault codes?

[FrankTheDog]

If you don't hear the fuel pump it's a good bet that the pump is shot.

Especially if there were no symptoms before hand.

I don't know how you would test it to find out but that's where I would start.

[Dadinator]

Did you check for fault codes?

None.

Hav 12v powrr supply i am gonna try on pump in future.

[dasbulliwagen]

There are several items on that 5 volt reference circuit. It could be any one of them bad bringing it all down. I'm not saying this is definitely your problem but its possible. Don't quote me bit I think the other items on the 5 volt circuit are the crank sensor, the throttle position sensor, the ac pressure sensor, coolant temp sensor. I've also seen a bad engine ground cause issues like this. Just more stuff to check. Good luck.

[Dadinator]

So the whole problem was the wire harness back towards the fuel pump was broken.

all good now. Thanks for the help.