Im in the midwest of the United States.

 

Last ditch effort! Ive taken the car to dealership to have diagnostic ran they checked the pcm and it is fine, they said the wiring was at fault but to diagnose it it would be 600 for 4 hours of work. So i brought it home and replaced the engine wire harness with one i know was a working one. To no avail the damn car runs for 15 or so min and dies. I have no idea what my next step is any advice will help before i just give up and part it out?

 

What are the LT trims?

What I think you really need is a great jag indy who knows everything about that specific era car+engine. About the worst thing is a car that's been messed with because you have no way of knowing how many faults may have been added that never occur in a real car..

 

update.. ive replaced the 02 sensors and both the cam position sensors and it still dies. Something just doesnt make sense i lose injector pulse but nothing else it still has spark it has power to the injector. Ive tried another pcm and same issue, i changed the harness and same issue. Ive checked the resistance of injectors cold and they average 12 ohms, when hot they are over 13 ohms, is that to much resistance? Could the injectors be drawing too much current and overheating the driver? Thats the only thing i can think of the injectors are the only things not replaced.

 

I'd stop spending $$$ changing parts and use OBD (post #23 & others). Start with LTFTs, and check every sensor you can (ECT, IAT, ...) for plausibility.

Or follow the rest of #23.

The snag is that you know someone's messed with it so almost any weird thing could be wrong - could be something that never happens with any other 4.0.

Unless they put in a full set of the wrong injectors I don't see how all 8 could go bad in the same way and all at once i.e. I think you're heading in the wrong direction to suspect them.

For it to be something in common for all 8 you'd be looking for something like a wiring fault where heat or vibration upsets it. Most things on these cars are live and when activated pulled down to ground so you'd be looking at the live (have power available) all the time not the ground side. You can see this clearly in the Electrical Guide, which is essential.

 

The fuel trims were checked when I took it to the dealer and was told they were fine.

 

As it dies they're still OK? I bet they never looked!

Still, you can always sell the car.

 

They are It ftrm1 21.1
lt ftrm2 16.4
At idle

 

Those are miles out!!

Read other threads about trims.

 

I thought they were high as well, I put vacuum gauge on it and has 19 inches of vaccum. Now they are closer to 30 on the trims. I did spray some carb cleaner and no noticeable leaks.

 

Yes those fuel trims do point to a problem but I am still surprised there are no codes?

When I had large fuel trims I got the old stand by P0171 and P0174 right away.

The 15 minutes is a head scratcher too?

Have you inspected the air intake system for cracks and holes?
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They're maybe just not quite so bad as to throw codes - but why care? Just fix 'em!

 

If you're driving or the engine is revved up does it die the same or is it only dying if at idle?

 

I haven't driven it yet but it does die at higher rpms as well

 

And the roughly 15 minutes of run time; is that only on a cold start or does it run about the same time each time it restarts?

 

Only first time, runs 1 or 2 minutes after restart then dies. Longer it sits,it stays running longer.

 

Just a thought, check to see if it dies right as it goes to closed loop. I've never checked how long it takes, may not be related.

 

Update...

I finally got the fuel trims fixed. Vacuum leaks plus bad maf sensor. But it didn't fix my dying issue. One thing i did notice is the temperature gets to 228 but the guage reads right in the middle. The fan comes on but the temp doesn't drop much maybe a couple degrees. it has new temp ect sensor.

 

228 sounds too high. What does the workshop manual say for your car?

Also, I've never heard of the gauge with 228 being in the middle.

I think your 228 is wrong... What tool are you using?

What are your LTFTs now?

 

The Fuel trims are both close to zero. Between 0.0 and 1.0. I'm using an actron scanner. But I'm getting no hot air when heat is on think the dccv is bad.