96 zj

[dan]

i recently inheirited a very clean zj that has the 4.0 it has also been sitting for a year and a half, my uncle was driving it down 75 and it just shut off, he replaced almost every sensor there is and took it to a shady mechinc but had no luck with getting it going ( the garage should not be allowed to touch a car) my uncle died recently and my aunt decided to give me the jeep so what im trying to figure out is whats wrong with it it has spark has fuel and the timing is good so any input would be very appercated

[WrenchMonkey]

My first thought is that is that if you've got good fuel, spark, and timing, it would run. Are you sure?

The "just shut off" sounds like a cps. But then you'd have no spark, and fuel pressure, but no injector pulse...

[humpy]

Correct me if I'm wrong but 96 should be obdI... I'm pretty sure u can buy a $20 book at advance and go thru the code reading procedure.. Use a paper clip and cross the 2 pins and however it flashes, match that with what the book says... Will give u a starting point

[dan]

the cps has been replaced, and i have no codes being thrown, with good fuel and spark i figured it would run but nothing it cranks and doesn't run and i cant think of what else it could be

[dan]

just noticed that the sensor for the oil sensor unit has the wiring harness female part broke off would that not let it start???

[comanchedude]

open the air intake tube spray starting fluid into the intake crank it over... if it indeed has spark it will fire... now if that works you have a fuel delivery issue... if it don't fire you are not getting spark. start there.

[race4fn]

Basiclly what comanchedude said is the best way to start, just had similar issues with a
96 xj, ended up having low fuel preasure so I replaced pump, coil was going bad so i replaced it and
had to replace cps with a factory one....guess autoparts store cps are spotty at best...
You can check resistance on cps, and on coil....also fuel preasure...

[blazerbrad]

Originally Posted by dan

just noticed that the sensor for the oil sensor unit has the wiring harness female part broke off would that not let it start???

Not sure but there is a chance that the ECM will shutdown the engine if it senses no oil pressure.

When you say "good fuel" what do you mean? Fuel pressure good, injector pulse width signals?

[cincygman]

A 96 is OBDII

[dan]

When you say "good fuel" what do you mean? Fuel pressure good, injector pulse width signals?[/QUOTE]

it has good pressure and good injector pulse

[itbrokeagain]

My bet is cps

[dan]

the cps is new but from what i understand its a 50 50 shot getting one from autozone

[race4fn]

Thats where I would start, mine was autozone cps and had to replace with jeep one..

[Coppertop]

A bad CPS = no spark.If you have spark,than the CPS is good.I would try the starting fluid recommendation from Tom(Comanchedude).Also, a compression check,along with a spark plug check...

Good Luck
Nick

[WrenchMonkey]

Any progress?

[underpowered]

something to check is on OBDII Zj's, a loose connection at the PCM will cause them to shut off. check the PCM plug. unplug, clean, plug it back in.


if it truely does have spark, fuel, and is in time there is absolutely no reason it should not start at the minimum.