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Running real HOT!

J

JungleXJ

NAXJA Forum User
Location
Malaysia
My 94 XJ HO is running hot even though I just changed my radiator to a 3 core! Its only running hot on load, high speeds and when the trail is muddy and climbing up a hill or incline. The water pump and thermostat is about 8 months old. Was burped once from the temp sensor location once.

Some of the mods done to my XJ:

- Banks Header
- K&N Cannister Filter
- Bored Throttle Body
- Throttle Body Spacer
- No cat.
- 4.56 R&P

On idle she will slowly drop back to about 210*F/100*C but if pushed she can go up to as high 230 or more but by then I would run my heater to bring her down lower. Has not gone to the red zone yet. Am I running lean? Thanks for any help.
 
JungleXJ said:
. Am I running lean? Thanks for any help.
Click to expand...

With the mods that you have so far, I think there's a good chance that you ARE running lean. Check your plugs. If so, build a MAP adjuster and crank up the MAP voltage to richen it up a bit.
 
Yes Electric fan does come on, will pull a plug out to see if I am running lean and check if my hoses are collapsing.

Dr Dyno, what would be easier/better, to build the MAP adjuster or to move the IAT sensor away from the manifold to the intake tube?

thanks guys
 
Haven't had the chance to pressure test the radiator but will get that done soon.

Made myself a MAP adjuster, cranked up the voltage but I every once in awhile the Check Engine light comes on.. with the MAP sensor error. What gives?
 
JungleXJ said:
Haven't had the chance to pressure test the radiator but will get that done soon.

Made myself a MAP adjuster, cranked up the voltage but I every once in awhile the Check Engine light comes on.. with the MAP sensor error. What gives?
Click to expand...

How high did you increase the MAP voltage? Maybe you've gone too far and that's why the CEL is coming on.
 
My stock 94 4.0ho motor was doing the same thing yours is doing what I found was that my electric fan wasn't coming on until It was almost running in the red so I fixed it so it comes on whenever the key is turned on and that fixed it (suprisingly).The only problem I have now is in the winter it takes a little longer for the heat to start kicking out hot air.
 
Couple of updates...

Electric fan has been wired to be controlled by a switch that will bypass the thermo and the a/c so I can have it permanently running.

Will check the MAP adjuster, I had it cranked up to 6v. It seems ok most of the time but will stumble and the check engine light will come on. If I by pass it (back to 5v) it runs fine, will check the resistor. Seems to run cooler tho!

Thanks
 
Try Checking the clutch fan (mechanical fan)? It should barely spin by hand when the engines is at 210+.

Make sure you turn the engine off first though? :)
 
Just an update...

Runs cool now... the Map adjuster works great now. I did a reset(disconnected the battery) ran rough initially but after the second start and a short run, she runs beautifully and much cooler!

Thanks everyone for all your help especially Dr Dyno!
 
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