Replaced the temperature sending unit with the correct one from autozone and it still reads low. I may pull the thermostat housing and put in a 195 just in case it's stuck open or something. Not sure why all the temp sensors would be wrong.

 

Didn't you say the IR gun showed the correct temp at the thermostat housing? If so, your thermostat is working

 

It did most of the time I was checking it again yesterday and it was around 180 so I could've pointed it slightly differently or something but it's still up there a bit. I drove the Comanche an hour today and it didn't even hit the first line

 

Sounds like you have air trapped in the system. A bubble at the thermostat housing would explain the different IR temps, and one at the back of the head is common to cause low temp readings

 

I have a 97 xj 4.0L sport

Is the windshield washer fluid tank inside the driver side fender?

Reason I'm asking is because I'm thinking about buying a snorkel and if it's on the driver side, wouldn't the washer fluid tank get in the way?

 

#1 yes
#2 yes
#3 you do a lot of water crossings? Snorkels look cool but there are a lot of drawbacks.

 

Any tips to get air out? I've never had issues with it before

 

Officially, the air is supposed to work its way out on its own. In reality, that doesn't always happen.

The cleanest way is get the Jeep up to temp and aggressively massage the coolant hoses, squeezing then firmly in different places on each hose. The pressure fluctuations can push out trapped air.

The method I normally use is to raise the rear end of the vehicle so the temperature sending unit at the back of the head is the highest point in the system. I remove the sending unit while the coolant is cold, run it until no more air is coming out of that port, and then I reinstall the sending unit. During that process, I still kneed the coolant hoses.

It may or may not fix your problem, but it's free and doesn't take long to try it

 

I'll give it a shot when I get home

 

What kind of drawbacks? I don't want any drawbacks lol. Aerodynamics? No I don't do a lot of water crossings I just think it could help a little with water but obviously water will never get above the hood

 

I suggest looking at the "cowl snorkel" upgrade option if you haven't yet. It increases your fording ability without sacrificing power

 

Well I made it back, but then I went to the auto parts store and it was hesitating really bad and barely had any power at all and I thought I was going to be stuck on the side of the road. I think it may be something in the fuel system since it felt like the one time I ran out of gas. I'm really hoping it isn't the fuel pump, but anyone have any suggestions of the best place to look? I plan to run to the parts store and grab a fuel pressure gauge and see where it's at. Speaking of, does anyone know off the top of their head what the pressure should be?

 

lol... funny thing is, I was just thinking that doing it like that would probably work, then I read this.

31 PSI at idle and 39 PSI at WOT

Don't automatically jump to the fuel pump. Could be the fuel pressure regulator on the rail, could be the o-rings on the FPR, could be the fuel filter too... especially if the truck sat for a while.

 

29ish at idle and when I give it gas it drops to mid 20s I went ahead and grabbed a fuel filter while I was at the parts store so I might just throw it in since it had sat.

 

Haven't test drove it yet because I can't find where I put the stupid cap for the fuel rail and I don't want to drive off with it on the jeep somewhere, but I think even if it wasn't the fuel filter it needed to be replaced anyway that's the color of the gas that came out


EDIT: update after test drive. Much better, much more power and the fuel pump is silent instead of the buzzing it usually has. Still has a hesitation around 2000 rpms and is a little jumpy, but if I shift there's no more hesitation, or if I just floor it from a stop it'll go all the way to redline without any hesitation, just cruising at or slow acceleration around 2000 rpms gives me hesitation.