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?
Engine shuts off after running for a while
- Thread starter kprn1361
- Start date
In full disclosure I'm not completely familiar with the YJ platform.
But, I have read quite a bit about failing Crank Position Sensors (CPS) acting in this way.
But, I have read quite a bit about failing Crank Position Sensors (CPS) acting in this way.
I agree with JeepJoe. It sounds like the CPS. I had the same issue. Mine would die unexpectdly. I would have to wait around for about 10 minutes to start it back up.
When a CPS goes bad, the coil inside I believe splits when it gets hot. This causes the Jeep to stall. As the coil cools,it shrinks back down, and completes the connection allowing you to start the Jeep again.
A CPS failure will throw an engine code, but will not turn the engline light on. When the Jeep dies again, check your codes. If you get a code 11 then that will be your CPS or camshaft sensor failing. Odds are is that it is the CPS.
KKanoza58
New Member
Hello...just joined up. This forum is GREAT. I see this discussion is from 2021, so I'm not sure it's still alive??? I have a simular problem with my 95 2.5 l. Runs fine until it gets to operating temp and just stops running...done all the diagnostics that I could think of...here's my question. Wouldn't bad sensor like the Crankshaft Position Sensor, throw a code? The only ones I get are 12, 33 and 55 which aren't problematic! I guess I should take it out and test it, but then it wouldn't be at the hotter temp... Maybe heat it up eh? I've looked at the BIG 3 for problems...Air, Fuel and spark, I've narrowed it down to spark, so I guess I'll just keep on testing/trying!!??
Any feedback would be welcome...Thanks, Dudes!
Any feedback would be welcome...Thanks, Dudes!
redbullet
YJ Enthusiast
Try getting a new cps. If it does not help, return it or keep it as a spare.
KKanoza58
New Member
Thanks ...I'll consider giving it a shot. I've never replaced the CPS on this YJ, so I guess a new one wouldn't hurt. Pretty easy to install. You think the temperature has something to do with it conking out then??
Is your 2.5 Auto or manual? You will need a spacer put on the head of the CPS if your transmission is an auto. I've heard people layering stickers, but I am not sure how thick. We are talking millimeters. Napa sells them, but it is $10 for one. If you have a manual transmission, then no worries. No spacer needed
KKanoza58
New Member
KKanoza58
New Member
Howdy,
Well I'll knock on wood...but I think I got the stalling issue licked. I did replace one "CPS", the Crankshaft position sensor. It fired up and I ran the engine at the house for about an hour to make sure I could trust in traffic. I took a short trip to gas up and went back home. No issues. Next day I took it out on our local highway and it did fine!! (All the cleaning and replacing I've been doing has the old girl running like a roadster). So, I almost got it home...died on me!! WTF? I tried popping the clutch while I was coasting, but that didn't work, So I stopped and waited for no more than a minute and it started up immediately. I got home that night. Next day after work I went back out to work on it and it just cranked, no start. I went around to all the connections, wires, harnesses, ect. and jiggled everything. Tried starting again...BAAM, started right up and continued running! I knew something had to be shorting out so, while it was running I went back and jiggled everything again and lo and behold when I barely touched the Camshaft position wire, it died! Glory...I took off the dist. cap and that 3 wire harness was practically worn in half! I'm waiting for the new other "CPS" I ordered to come in but in the meantime, I separated the 3 wires with elect. tape, put everything back and I've driven to work the last 2 days with no issues... I never got any codes indicating a problem, but I truly believe this was the issue. I'll let y'all know how it goes after I put the new one from CarParts in. It was pretty cheap, so I hope it's not a DUD.
I appreciate this Forum and your input!!! KK
Well I'll knock on wood...but I think I got the stalling issue licked. I did replace one "CPS", the Crankshaft position sensor. It fired up and I ran the engine at the house for about an hour to make sure I could trust in traffic. I took a short trip to gas up and went back home. No issues. Next day I took it out on our local highway and it did fine!! (All the cleaning and replacing I've been doing has the old girl running like a roadster). So, I almost got it home...died on me!! WTF? I tried popping the clutch while I was coasting, but that didn't work, So I stopped and waited for no more than a minute and it started up immediately. I got home that night. Next day after work I went back out to work on it and it just cranked, no start. I went around to all the connections, wires, harnesses, ect. and jiggled everything. Tried starting again...BAAM, started right up and continued running! I knew something had to be shorting out so, while it was running I went back and jiggled everything again and lo and behold when I barely touched the Camshaft position wire, it died! Glory...I took off the dist. cap and that 3 wire harness was practically worn in half! I'm waiting for the new other "CPS" I ordered to come in but in the meantime, I separated the 3 wires with elect. tape, put everything back and I've driven to work the last 2 days with no issues... I never got any codes indicating a problem, but I truly believe this was the issue. I'll let y'all know how it goes after I put the new one from CarParts in. It was pretty cheap, so I hope it's not a DUD.
I appreciate this Forum and your input!!! KK
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
no drive line told, 2.5L , 4.0L stick or automatic. (hint 1, the CKP is not the same on all those) ok other posts show 2.5L like mine.
of 50 causes of stalls CKP is just 1,.
CKP with 2 holes just bolts on , with 1 hole, it has to be gap ed or fails hard. ( the right CKP must be used and installed as the books says FSM)
okay> not only shorts cause it but opens, both. in EFI, systems.
so dizzy is bad, id replace the whole thing, (lazy bum me)
yes the codes only store , 5full seconds of cranking a dead engine, and is not easy to discover, ever, if intermittent CMP.
the DRB tool would see it fail. but nobody has a OBD1 tool here. ( not sold now, unless $5000 used is cheap to you)
I shop rockauto for best deals, and get more choices on QUALITY branded parts. I buy CARDONE rebuilt distributors. USA company too.
ask how to do the dizzy swap it is tricky with the gear drive. the 2.5l dizzy clamp is horror to reach. 4.0 easy. a/c mount pulled. pain.
if chose to do so.
yes this way.
this is just 1 way to buy one, I don't car how, just 1 simple example. btw, I have zero to sell ever, SMP makes top grade products.
1993 JEEP WRANGLER 2.5L L4 Distributor Pickup Coil | RockAuto
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