Motor wont run... need help

My93xj4.0 · Jan 13, 2017

So this is my first post on this site. I've never needed advice more than now, so hopefully someone can help me. 93 xj 4.0 H.O, 250,xxx miles, auto 4wd

Symptoms:

Starts right up in the morning, dies after driving intermittently

Won't start back up untill i wait for a few minutes

Fluctuating temp guage

Codes 11 and 12

Parts replaced:

Fuel pump/filter/relay/pressure regulator

Coil/distributer

Crank position sensor/map/throttle position sensor

Other work recently done before problem:

Radiator replaced

Thermostat replaced

Ac condenser trashed

Coolant flush in progress

I've tried everything i can think of to get it running besides replacing the computer. Does anyone have any ideas?

90xj06 · Jan 13, 2017

11 is showing no crank signal. it could be the cam sensor in the distributor. or the wiring to the crank sensor has melted on the exhaust.

12 is because the battery was disconnected within 50 key on cycles.

My93xj4.0 · Jan 13, 2017

90xj06 said:
11 is showing no crank signal. it could be the cam sensor in the distributor. or the wiring to the crank sensor has melted on the exhaust.

12 is because the battery was disconnected within 50 key on cycles.

I've replaced both already

90xj06 · Jan 13, 2017

check the wiring. but its not uncommon to get a bad part. does the rpm gauge blip up at all when cranking?

My93xj4.0 · Jan 13, 2017

90xj06 said:
check the wiring. but its not uncommon to get a bad part. does the rpm gauge blip up at all when cranking?

The rpm gauge doesn't move until the motors running.

90xj06 · Jan 13, 2017

it should pop up off the stop just a bit. as the rpm should be ~300 when cranking.

My93xj4.0 · Jan 13, 2017

Well it doesn't. Im not sure if it ever has, but if thats the problem what needs to be replaced?

My93xj4.0 · Jan 13, 2017

90xj06 said:
it should pop up off the stop just a bit. as the rpm should be ~300 when cranking.

Well it doesn't. Im not sure if it ever has, but if thats the problem what needs to be replaced?

90xj06 · Jan 13, 2017

i would inspect the wiring to the crank sensor wiring. its common for those to get a bit to close to the exhaust and melt.

PhotographerMike · Jan 13, 2017

I had a CPS that was bad out of the box with thermal failure. I checked it by heating it in the oven. Warmed up, fail. Cooled, just fine.

My93xj4.0 · Jan 13, 2017

PhotographerMike said:
I had a CPS that was bad out of the box with thermal failure. I checked it by heating it in the oven. Warmed up, fail. Cooled, just fine.

How do you test it?

My93xj4.0 · Jan 13, 2017

90xj06 said:
i would inspect the wiring to the crank sensor wiring. its common for those to get a bit to close to the exhaust and melt.

Wiring looks good.

PhotographerMike · Jan 14, 2017

My93xj4.0 said:
How do you test it?

Here's my original post from 9+ years ago. Haven't had the same problem since then and 40K miles.
Post #10 has the numbers.

http://www.naxja.org/forum/showthread.php?t=935756

Mike

Motor wont run... need help

My93xj4.0

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