Starting issue after radiator cap came loose

[Kinardg7]

Saturday morning I went hunting and when I stopped to get some gas, I noticed something wet on the front fenders by the hood. Didnt pay it much attention since it was rainy out. Went on to my hunting land and the jeep was fine. No issues starting or running hot. I get done hunting and head home (no luck btw) and decide to stop and grab some lunch. Looked down at the temp and it was around 230. Left my fan running for maybe 10 min as I went in the store and got some food. Come outside and temp was at 240. So I thought driving it home and checking on it would probably be the best option (it wasn't) When I was backing in the garage I noticed steam coming from the hood so I opened it up and saw my whole engine bay covered in coolant. Apparently I had not put my rad cap all the way on a few days back when I was checking the fluid. I put my battery maintainer on the jeep and left the fan on for a few hours to cool it down so I could fill it back up and make sure all was well with the cooling system.

This is where my issue started... I got the jeep running and was letting it get up to temp so I tried to rev it just a little by manipulating the throttle body and it started to die as I messed with the throttle body. A few seconds later it cut off. I haven't been able to get the jeep running again since. It turns over like normal but just wont crank fully. I checked the fuel rail as soon as it cut off and it didn't squirt out as much as it normally had when id see if the injectors were getting fuel.

I'm under the impression its the fuel pump because ive had issues with having to turn the key a few times to get it started, but I'm not *certain* its the fuel pump. I already have a Delphi pump ordered and should be here tomorrow (11-1)

 

[P man]

So you are thinking it's a coincidence the fuel pump diesel around the same time as the coolant explosion?

I would lean more towards a sensor being soaked or something along those lines.

 

[Kinardg7]

So you are thinking it's a coincidence the fuel pump diesel around the same time as the coolant explosion?

I would lean more towards a sensor being soaked or something along those lines.

Maybe it’s a coincidence but I just just got home and the Jeep actually started up this time. But when I go to hit the throttle it dies down. Any idea?

 

[P man]

Maybe it’s a coincidence but I just just got home and the Jeep actually started up this time. But when I go to hit the throttle it dies down. Any idea?

I would not put a fuel pump on it..if it were me I would start by cleaning the engine compartment with some simple green or your favorite degreaser and get the coolest cleaned off. I would then let everything dry and I would take each connector off of each sensor and clean and dry it.

I just can't believe the fuel pump would have shit the bed at the same time it could happen but not likely

 

[sab]

If you ran it out of coolant, and it ran hot for any significant amount of time, you likely have engine damage. Your engine could have seen much higher temps than the 240 max mentioned in your post because once you lose coolant, the temp sensor is measuring air temp in the empty coolant system. I don't have much experience with the 4.0, but typical engine damage from overheating can range from a blown head gasket to a warped or cracked head, to failed bearings. If you're not an engine guy, I suggest taking it to a mechanic for diagnosis.

That said, I'm hoping that P man is right, and it's just a wet sensor...

 

[sab]

By the way, I agree that it's highly unlikely that it's the fuel pump. It's unaffected by engine coolant and temps.

 

[Kinardg7]

New development, the engine starts with the fuel pump relay out. Soon as I put the relay in, it dies.

Not sure if it matters but I have manual gauges since none of my dash gauges work. I checked oil and it looks how oil should look (not mixed with water)

 

[TNHEADDUCK]

Spray some starting fluid in it if you want a quick way to see if it is a fuel issue, it wont hurt it.

 

[Moglocker]

New development, the engine starts with the fuel pump relay out. Soon as I put the relay in, it dies.

Not sure if it matters but I have manual gauges since none of my dash gauges work. I checked oil and it looks how oil should look (not mixed with water)

You leaving the fan on(I guess you run an electric fan)does nothing to cool the engine down,you would also need an electric water pump.

 

[Kinardg7]

You leaving the fan on(I guess you run an electric fan)does nothing to cool the engine down,you would also need an electric water pump.

Okay. Thanks for the info but it doesn’t help me fix the issue at hand. I’ll keep that in mind next time I go to leave the fan on.

 

[Moglocker]

Okay. Thanks for the info but it doesn’t help me fix the issue at hand. I’ll keep that in mind next time I go to leave the fan on.

New development, the engine starts with the fuel pump relay out. Soon as I put the relay in, it dies.

Not sure if it matters but I have manual gauges since none of my dash gauges work. I checked oil and it looks how oil should look (not mixed with water)

Let it all dry out good

 

[Kinardg7]

UPDATE- Replaced the fuel pump assembly and the Jeep runs just fine. I also got a new radiator cap since they are super cheap. Hopefully that was why the cap came off.

Took it on a test drive and everything is fine other than when I shift into 2nd, 3rd, or 4th, I go to give it throttle and it almost feels like an air bubble in the fuel line. It’s an odd thing and I’m not really sure how to explain it other than that.