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Discussion Starter #1
Sorry this is so long, I wanted to put everything that I have done so far.

My 93 grand with a 5.2 will run for about 40 mins from a cold start and then cut off.(that's at idle) It will start right back up and run for about 5-10 mins then cut off again. This goes on and on. For the most part if idling it will start right back up. Now I driving and it cuts off it will backfire when I pump the gas. If it starts to die you can not save it. Then I have to wait a few mins for it to start back up. When I check for codes I get none. I have replaced a lot of stuff for different reasons. The coil, plugs, wires, cap, and rotor are new. Old wires were bad they jumped spark so when I change them and did a tune up. Old coil tested bad, also tried a spare, but one it now is new. It has a new tank, fuel pump (MSD outside tank) and a fuel pressure regulator. Old fuel pump went out with a full tank of gas so I cut out floor in hatch to get to the pump and cut the old tank. Had fuel pressure problems that's why I have a new regulator. Broke and replaced crankshaft position sensor when I put the motor in about 2,000 miles ago. Now I have a parts jeep and have switch out the camshaft position sensor and the PCM. I also have a new redtop in it. All cables are 2 gauge and have redone connections. Voltage level is good, I have a high output alternator. I dont know what to look at next. Today I was reading about the ASD relay and it said that if the jeep over heats that it would get shut down. My gauge pegs hot when I start it up. I have replaced the CTS and gauge and it still happens. So maybe the PCM is cutting it off because it thinks it is over heating? It is not a fuel problem. I have run it with a pressure gauge and a timing light on the coil wire. Pressure stays good ,31 psi, goes to maybe 40 when it dies. When it dies or wont start it is because there is no spark. Any Ideas would be a great help!
 

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The only time I experience a block catalytic converter I lost power at higher RPMS. This was on a 82 Z28 Camaro.

I don't think you said anything about O2 sensors, how many miles on the one's you have on the motor?
 

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Have you been wheeling in the recent future particularly in the mud? Im thinking you may have a severely clogged cat.


Also moved to the correct section.
I didnt know he was from the future
 

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is the engine that you swaped in the same year as jeep you put it in? I ask for all kinds of reasons but wont get itto it till you say yes or no.
you say it will idle no problem and when it stops you have no problem starting it but when you rev or drive it will back fire and then hard to restart. so I will sujest this. is the camshaft sencer off the old engine that you took out of the jeep if so go get a new one..( for the year of engine that you put in if diferent from jeep)
it could be that it is sending wrong message and if the engine is backfiring it is loading up with fuel.... and the cam has intack and exhaust valves open at wrong time....
 

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Discussion Starter #7
The cat is gutted with a strait pipe. The motor is remanufactured. I have no codes other than that the battery has been out. The camshaft sensor was new with the motor but have switched out with the one from the parts jeep(same year and motor) and does the same thing. It will idle and drive fine for a short time. Less when driving. When it dies at idle it starts right up. When driving if you pump the gas to try and save it, then it back fires. If the PCM wanted to kill the motor because of a sensor reading would it do that though the ASD relay. The relay is closed until after the motor stops. I have power to the gas pump when it dies, but not the injectors or coil.
 

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Verify that your firing order is correct.
 

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Discussion Starter #9
Well I think I found the problem. The connector for the Crankshaft position sensor was not pushed in all the way. The seal was dirty so I know it was not tight. When I pushed it in the clip would not catch. I zipped tied it so it would not come apart again. I have drove it all around the mountain and has not cut off. Im glad I have a parts jeep. With out it I would have spent alot of cash. The things I did replace were bad and needed to be. I hope it works.
 
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