8 times out of 8 events in 2 months engine will not crank when attempted within 15 minutes after shutdown. Will always start after engine compartment cools for 20 minutes on cooler day hood up, 30 minutes on warmer day. Always starts from cold. Checked wiring, pulled/replaced plugs,checked starter relay, replaced starter but no joy. Battery strong, all instruments active when key "ON" or "START" position. Always cranks when starter control relay jumpered out, but relay coil not getting activate signal when compartment hot. Switched out relay but no joy. ****** Park sensor sensitive to heat?????
2002 3.7l will not crank/start when hot.
- Thread starter PocoLoco
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Bill our electrical specialist may be able to help re the park sensor.
In the meantime, possibly browse some of these heat related starting threads. https://www.google.com/search?q=jeepkj.com+wont+crank+when+hot&ie=utf-8&oe=utf-8&client=firefox-b-1
Hope this helps.
In the meantime, possibly browse some of these heat related starting threads. https://www.google.com/search?q=jeepkj.com+wont+crank+when+hot&ie=utf-8&oe=utf-8&client=firefox-b-1
Hope this helps.
Jimmyjimmyjimmy
New Member
Had similar random issue. Replaced Crank position sensor cured it.
If the starter relay isn't getting energized during the times it doesn't crank (as I think you're saying), you need to backtrack from there to the ignition switch in the column. If your Jeep is an automatic, you may want to check the neutral safety switch.
A bad crank sensor is not the problem, FYI
A bad crank sensor is not the problem, FYI
Jeep is automatic, that's why I speculated about park switch being sensitive to heat. The issue is completely in sync with powertrain being hot from prolonged running (more than 30 minutes including heatsoak) at time of turning off ignition. Wait 30 minutes and it has never failed to crank/start, now 10 times. If I start up from cold, and only run for a few minutes under low load, but enough to get coolant temp up to normal, I can shut down and restart immediatly ok. I'm going to investigate ignition switch and neutral sw but right now my money is on the transmission. Because it is a serious heat location under load, guess why they put in coolers, huh? Which same stop working with no fluid flow, as does fan.
Forgeot to mention: I can put the ignition switch in ON position, then go jumper the starter control relay to activate the starter solenoid, and the engine cranks/starts immediately. Repetitively. So at least the ignition function of the switch isn't a problem. Leading to suspicion that the rest of the switch is also ok.
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john e denson
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I had the same problem in my 05. I had replaced the cooling fan a few months before this started happening. I replaced the fan cause the blades had deteriorated. The pins in the new connection had shorted out. Straight wired fan and it has not happened since. I am thinking only low speed was working and not the high speed. I was gonna check the heat sensor under the battery next if it happens again. It sends a signal to the PCM too. jd
Pathfinder
New Member
I had the exact same problem, different vehicle. It had to do with the computer and it cost $200 to fix. I took it to a smog shop that could also do repairs and they were the ones who found it. Good Luck!
Ive heard of this happening from a weak fuel pump or from pressure leak in the fuel lines. In both cases air bubbles or vaporized fuel can cause start failure but only when the lines are hot, once the lines cool the fuel returns to liquidity
Billwill
Full Access Member
Actually the 05,06 and 07 KJs do not have the Temperature Sensor located under the battery...or anywhere else!
This despite the fact that some manuals do describe this Sensor and some Wiring Diagrams still show it!
My 2002 Export 2.5 CRD showed a "Charge" light on the dash when still quite new...Owner's Manual said check Alternator...was OK!
Traced this to a bad ground on my Battery Temp Sensor under the battery.
Jeep must have decided this Sensor was a waste of time and stopped fitting it!
Maybe I am wrong and you do find the Sensor but not from what I have heard!
DadOSix
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DadOSix
Full Access Member
Been doing a bit of searching for you.
It appears that the trs switch you are thinking of is part of the solenoid pack, not servicable separately.
Check out this thread from ram forums
www.ramforumz.com
Note - he is on an 05, but the TransEngineer discusses the start circuit. I know we don’t have digital prndl readouts, but the rest makes sense.
This Yt
At around 8:50 shows a test hack to see if your ground circuit is the culprit.
I would think for sure, on a cold jeep, his info proves nothing. But if you got it determined how it looks on your jeep, why not try this cheap test to help determine.
store.mopar.com
Your part above - some sites show discontinued, etc. might have to change the suffix to find the current version.
It appears that the trs switch you are thinking of is part of the solenoid pack, not servicable separately.
Check out this thread from ram forums
545RFE / Neutral Safety Switch / Transmission Range Sensor
Note - he is on an 05, but the TransEngineer discusses the start circuit. I know we don’t have digital prndl readouts, but the rest makes sense.
This Yt
xc_hide_links_from_guests_guests_error_hide_media
At around 8:50 shows a test hack to see if your ground circuit is the culprit.
I would think for sure, on a cold jeep, his info proves nothing. But if you got it determined how it looks on your jeep, why not try this cheap test to help determine.
2001-2004 Mopar Transmission Solenoid 4799934AD | Mopar Estores
2001-2004 Mopar Transmission Solenoid 4799934AD
store.mopar.com
Your part above - some sites show discontinued, etc. might have to change the suffix to find the current version.
DadOSix
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john e denson
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Well, I am back. Had a no-crank problem the other night. IT had been fine for weeks. I had run a few errands in town with no problems. The temperature gauge never moved past the middle. At first, when it would not start it seemed to have no power to the starter. Nothing at all. Then gains power and makes a clunk. Wait a little more time and it cranks right. Drove it home. The next morning no-crank. Checked battery. It was fine. TRIED to start it again and it fired right up. looked for that heat sensor under the battery and there is NOT one there. That was 2 days ago and it has been cranking up just fine. I am baffled now that it would not crank when cold. Relaced starter about a year ago. The battery is less than 6 months old. I was thinking it is some sort of sensor cause of the way it cranks up. STUMPED
DadOSix
Full Access Member
Assuming you are OP
starter. Starter. Starter. Dead spot.
to tell fer sure, pull the starter and have it tested - or - next time it craps out, get a testlite or meter on that starter terminal and see that you are getting power.
old school - no start, rap the starter with a stick/hammer.
sometimes that is enough to bump it.
starter. Starter. Starter. Dead spot.
to tell fer sure, pull the starter and have it tested - or - next time it craps out, get a testlite or meter on that starter terminal and see that you are getting power.
old school - no start, rap the starter with a stick/hammer.
sometimes that is enough to bump it.
john e denson
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TY will try that the next time. Just seems strange that I get nothing. no click. then after a few tries, I get a click. then wait a bit. Then I try and it cranks right up
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