93 Crank but dies, or no start

[joe_peters]

Sounds like either your battery, your cables, or your connections are NO GOOD.

 

[hightime81]

it keeps coming back to the battery... connections are clean and fresh. i guess the cables could be bad...

i might bypass the battery completely and just use the other cars battery to see if i can get it to go! would a dead battery cause it to just drop out like that?

 

[Ecomike]

haven't tested the coolant temp sensor yet, which is the air sensor? and for all of those, don't i just need to test that they are getting 5+ volts from the PCM?

and just for giggles, i did try another primary plug to no avail. i will turn it to TDC tomorrow and then see where the rotor is pointing...

So picked up a new coil just to check, didn't install it, just made the connections and let it hang and gave it a shot. turned over real slow b/c the battery is low again and didn't start. figured i should try to jump it with a good battery, got it connected and went to turn the key, heard the pump prime and said a little prayer and click, everything died. no buzzer, no lights, no nothing. It was as if the battery had been removed... jumped out the car and checked to make sure i hadn't crossed the jump cables on accident and i hadn't. removed the cables and then re-connected them and the interior light comes back on bright as day. jump in and turn the key and click, it all dies again. did this one more time before i called it for the night.

thoughts? i killed my voltmeter earlier lol, but tomorrow morning i will check the fuses with the ohm-meter to see if i blew one.

No, NO, NO!!! The CTS, Coolant Temperature Sensor, and the Intake Manifold Air Temperature Sensor (IAT and MAT were two of the three acronyms I recall being used for it), are variable resistors, just like TPS, except the CTS and IAT/MAT resistance varies with temperature, not with gas peddle motion. If they give false readings of resistance to the ECU/PCM, they can starve the engine for fuel, or flood it before it can start! You need to look up the resistance as a function of temperature, check the sensors actual temperature (near ambient air if it has been sitting for hours at a stable temperature) and then using the ohms scale, loose sensor wires, not connected to the harness, read the resistance of the sensor. If it is way off from the factory spec, you have your problem!!!

Also, just for grins, try disconnecting the O2 sensor, and see if the engine starts and runs? I get the impression it has tried to start, but died with out ever really running for any length of time?

When my MAT went bad, the engine would only start late in the day (sometimes) when it was hot outside. Would not start cold at all lor int the morning, and the idle would go nutz all the time! Once it was running and hot, it would restart just fine.

New MAT air temp sensor solved that problem. The MAT and CTS have the same temp versus resitance values, and they are listed here in many older threads. Google it.

 

[Lowrange2]

Hey! I bought this Jeep!

Replaced the battery and I've been driving it since this a bit after this thread was started!