rebelbulldawg325

hey ya'll. i've gotta wrangler but this is for my brother. he's got a 93 GC limited with the 5.2 V8. when he cranks it, it will only run for a second or two then shut off. i know he's got a bad rear main seal leak, could low oil pressure be triggering a switch to shut down the engine? also, the exhaust is disconnected past the manifold, its been kinda cold here lately, could this have something to do with it? i'm not familiar with this engine at all and i have not looked at this problem yet myself, just what he's told me. i'm trying to get all the info i can so i'm ready to dig into it this weekend. also, i've found two different ways to pull codes from various resources online. one says to turn the key on and off several times and the codes will flash on the dash. the other says there is a DLC (data link connector) on under the hood on the passenger side mounted on the fenderwell near the front of the engine, could someone please verify one of these for me? thanks in advance

RRAM

sounds like he disconnected the battery or somehow activated the security. If you don't have the key fob to unlock the doors then use the key and lock and unlock the back gate and then do the same to the drivers door. if you have the manual it will tell you about it in there.
Do the the lights flash when you try to start it? I guess that should have been my first question.

rebelbulldawg325

the lights and what not dont flash when we start it. and we tried the unlock thing anyways and still nothing, we're thinking possibly an oil pressure switch but auto zone didnt have any. is there any way to jumper the switch just to test if thats the problem?

RRAM

if its an oil pressure switch problem I doubt very much its going to shut the engine off.
I would be looking more at a fuel problem or something like that. Might be your getting a fuel right at startup but the pump is to week to keep it running.
Does it start everytime you try it, then die. or is it hard starting start and die. You could try to either take the wire off the sending unit, and try it. And then ground the wire out and try it.
That is basically how those switches function anyway from my understanding.

rebelbulldawg325

i looked at it a little today. and it starts fine, but then loses fuel pressure. i wasnt too sure about the oil pressure switch thing either but someone told me they think the way the electronics on it work are theres a realay for the fuel pump that works on initial startup then it switches over to another realy after running through some sort of oil pressure switch, this makes sure there is sufficient oil pressure to run, if pressure is not adequate to run, the second relay never engages. i hate electronics. but like you said, lack of fuel seems to be making it cut off. whats wierd is it wasnt troubling to start or run before, it'd been running fine. he drove it. went inside somewhere for 20 or so minutes, came out, cranked it, then it shut off. been doin that ever since