Have a recurrent issue with my 1993. It will run for about 20 minutes, then all power shuts down. After it cools off, it will start, and run until it gets hot again. We replaced the ignition coil, and the fuel pump yesterday. We just drove it for about an hour, once stopped, it would not restart. Any ideas? Thinking maybe thermostat?
which engine and trans? I will do 93, 2.5L, 5speed MT?, answers. only. never post lacking driveline told or get wrong answers, YOU WILL. sorry it's a fact.
I see your fine post is now
hyjacked. (you meant all engine
power cuts off right not , full 12vdc power from battery cuts of correct?)_
lots of causes for YJ stalls or no starts, or shut down , and CPS/CKP are only 2 of many. (cranks fast but will not start is easy to diagnose)
that is a fact. it can be even a loose wire. (EFI endless ) FSM covers them all. page 1094 on.+
what matters most are 3 things when it is dead we can find it 10x more easy dead. so we do.
The ASD RELAY SHUT DOWN FOR LOTS OF REASONS, AND MAKES SPARK DEAD TOO AND FUEL.
ASD control runs both ASD relay and fuel pump control , relay coil pins. both. so if PCM cuts ASD it cuts FUEL TOO. see?
ASD drops for CPS or CMP dead. on all jeeps made. (MPI, not carbs)
ASD SEES ASD output overloaded (excess current ,shorts or voltage drop way low. pin 24 ASD. is monitored by PCM for overload. (prevents fuel fires !)
shorted alternator pin2,called A142 pin (from ASD
nothing on the car wired to A142 can be allowed to short. (means draws way too much current)
I use a voltmeter to monitor A142 feed pin.
the spark coil shorted is A142 too. spark HV coil primary pin shorted, but new so is not shorted.
the 02 sensor heater shorted(its guts)
the 02 wire heater lands on hot exhaust melts and shorts A142 and the WORLD ends ! super super common cause this. 3000f exh hits wire, factory clamp long ago missing, as mine was and not now.
any of 4 to 6 injectors shorted the ASD +PCM senses that and shut down fast. ( pure logic in PCM dicates that on all mpi cars made (gas)
PURE PCM logic, (the anti crash and burn laws) ASD is that.
if spark ends (sensed or cmp/ckp dead, the PCM cuts fuel (hard PCM logic there)
The FPR can fail and loose all fuel pressure or is 2 times too high and floods fuel, and stall;s
What I do is monitor the ASD output any time any jeep stalls or fails to start or only runs for seconds. the ASD is first. and is a standing 2 legs test. no bath in fuel. (yet, fuel bathes are last if ever, in my book)
same goes fuel rail pressure tests , me standing,. gauge tests.for sure if ASD does not drop out, cranking, dead engine 38 PSI cranking is next.
ASD pin 24 (cavity #) relay E, 3rd relay from right end of PDC fuse block
Pin 24 is , A142 feed. ( the most important wire EFI)_
the xxxxxx07 relays are all 4 the same in mine so horn relay can be used for spare, ASD, pump and starter relay. swaps it even on the road. failed
i pull asd and sneak a tiny wire into cavity 24 and put back the relay and use a $15 volt meter to see what 24 does, says up to 12vdc cranking it must
if not the PCM shut the ASD on PURPOSE by DESIGN,and now told you why above
good luck find stalls
I am electronics guy ,retired at 61 years old. (on purpose