Novak Conversions Jeep Wrangler TJ radiator

No fuel when engine is hot: Fuel pump, ASD, PCM, sensors, heat?

Liberated

Liberated

TJ Enthusiast
Original poster
Joined
Aug 23, 2018
Messages
119
Location
Northwest Ohio
Hi guys. I've been searching the service manual, and the forum and haven't been able to get find an answer. Forgive me if this has already been answered somewhere else, because I haven't been able to find it.

When my engine gets hot, and stays that way for several minutes, I lose power to the fuel pump. Engine will turn over all day, but no fuel.

Istill have ground back there, and have checked it good across the fuel sensor power in the same connector, even afrer dying. My fuel pump relay is good. I've attached below a picture of the relay. At one point I found the pinout for the relay(in the fuse block) in the service manual, but now I can't seem to find it again. Once it dies, I have power across 85-86, and 30-87. 87a appears to be open.

78279


Do I understand correctly that if 87 is closed, that the automatic shutdown(asd) is engaged? If that's the case, what kind of sensors or what have you could be bad to engage that? I replaced the CPS about a year and a half ago (along with the tps I think)

I'm hoping it's not the PCM itself, but am tired of chasing this gremlin.

I do what I can and learn as I go, but I don't have a large understanding to start from. Your knowledge would be much appreciated.
 
I had the same issue. 05 Unlimited after driving around my jeep would just die and wouldnt start right up until 40 min or so. I had PCM issues and replaced and I also found my ASD caused the shut down. I swapped the ASD with the horn relay and the engine ran for hours without shutting down. All this after I changed the fuel pump, crank position sensor and cam shaft sensor. Well everything is in working order now.
 
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So in your case it was the ASD relay? I'll try swapping them tomorrow! Thanks. If not, maybe it's time to look into the PCM... 😣
 
I have the same problem running gets warm will start back up to close down I’ve changed all my relays still does it can anyone give me an idea what it could be my relays are all getting very hot
 
There are several items that can cause this problem when the engine/compartment are hot.
The engine/compartment heat creates electrical resistance in wiring which can cause voltage going thru the relay magnet to decrease and the contacts to drop out. When the relay contacts open due to and increase in resistance caused by the heat; measure the ohms resistance across relay terminals 85/85 and if more than 75 ohms you should purchase a quality (not Chinese CRAP) and replace the relay.
When the engine will not start due to exposure to continued engine/compartment heat; open the engine compartment and locate the CPS (Crank Position Sensor) on the transmission bell housing. Pour a small amount of water onto the CPS and attempt to start the engine; IF the engine starts the problem is your CPS.
NOTE: This procedure of pouring water on the CPS will only work a few times until it no longer works; so replace the CPS as soon as possible.
 
Novak Conversions Jeep Wrangler TJ radiator
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