Project Bi-Polar
#16
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Year: 1991
Model: Cherokee
Engine: 4.0L HO
Thanks, ill be pulling all the vinyl off and either replacing it with new trim or painting the bottom half of the Jeep, from the top trim edge down, flat black. Probably take all the trim off and fill the holes with bondo. Its a work in progress, I need to find a better job before I can start anything major. Then I can get a welder so I can start doing fabrication work.
#17
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Year: 1991
Model: Cherokee
Engine: 4.0L HO
Still having an issue with it overheating at idle after a long drive. The electric fan is not kicking in automatically when it gets hot, but it will kick in if I turn on the AC. Logic is leading me to a bad Temp switch but as I have a 91 I am finding conflicting information about where it is located.
I've found that this year has 2 Temp sensors, a sender for the gauge and a switch for the fan. I've also found out the fan is not controlled by the engine computer just by the switch and relay system. One sensor is located in the block at the rear of the engine on the drivers side, the other is located in the thermostat housing. I'm getting conflicting information about which sensor does what job. Anybody have any experience with a 91 HO 4.0?
I've found that this year has 2 Temp sensors, a sender for the gauge and a switch for the fan. I've also found out the fan is not controlled by the engine computer just by the switch and relay system. One sensor is located in the block at the rear of the engine on the drivers side, the other is located in the thermostat housing. I'm getting conflicting information about which sensor does what job. Anybody have any experience with a 91 HO 4.0?
#18
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Year: 1991
Model: Cherokee
Engine: 4.0L HO
And I figured it out, temp sensor on the thermostat housing is not linked to the temp gauge. Disconnecting it starts the electric fan, which tells me it's a resistance circuit. As the temp rises so does the resistance which cuts the circuit and kicks the fan on. Means the sensor is bad or corroded or dirty, ordering a replacement and I'll fix it this weekend.
#20
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Year: 1991
Model: Cherokee
Engine: 4.0L HO
So To-Do list for the Jeep so far:
finish wiring my switches to their appropriate relays/circuits, cooling fan, lights, etc.
replace temp sensor
remove the roof rack, strip it down and paint it with black bedliner
mount and wire auxiliary reverse lights on back of roof rack
remove "wood" trim and repaint lower rockers and doors
remove/trim fender flares
fix/replace header panel (its cracked)
install H4 headlight housings
strip off valve cover, clean, paint, reinstall with new gasket and PCV, etc
fluid change on trans and tcase, trans filter change and strip pan to replace gasket
replace front and rear brakes, rotors, pads, shoes, drums, flush brake fluid
flush radiator fluid
cowl snorkel, I think Dukie did the write up for that
remove, strip and repaint intake manifold, reinstall with new gasket
fab up some kind of heat shield between exhaust and intake manifolds
Parts left to acquire:
Welder
got a line on a Zone off road 4.5" AAL lift kit and RE trackbar for about $600
Rough Country LCA drop brackets
need to swap in an NP231 with linkage and shifter so I can do an SYE with driveshaft
15x10 wheels and 33x12.50x15 off road tires
front and rear DIY bumpers from jcr
front winch
exhaust and intake manifold gaskets
exhaust header
4 hole injectors
finish wiring my switches to their appropriate relays/circuits, cooling fan, lights, etc.
replace temp sensor
remove the roof rack, strip it down and paint it with black bedliner
mount and wire auxiliary reverse lights on back of roof rack
remove "wood" trim and repaint lower rockers and doors
remove/trim fender flares
fix/replace header panel (its cracked)
install H4 headlight housings
strip off valve cover, clean, paint, reinstall with new gasket and PCV, etc
fluid change on trans and tcase, trans filter change and strip pan to replace gasket
replace front and rear brakes, rotors, pads, shoes, drums, flush brake fluid
flush radiator fluid
cowl snorkel, I think Dukie did the write up for that
remove, strip and repaint intake manifold, reinstall with new gasket
fab up some kind of heat shield between exhaust and intake manifolds
Parts left to acquire:
Welder
got a line on a Zone off road 4.5" AAL lift kit and RE trackbar for about $600
Rough Country LCA drop brackets
need to swap in an NP231 with linkage and shifter so I can do an SYE with driveshaft
15x10 wheels and 33x12.50x15 off road tires
front and rear DIY bumpers from jcr
front winch
exhaust and intake manifold gaskets
exhaust header
4 hole injectors
Last edited by at05gt; 12-30-2015 at 04:43 PM.
#22
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Year: 1991
Model: Cherokee
Engine: 4.0L HO
So I was playing around with the cooling fan relay, trying to figure out how to engage it manually. If I tap terminal 85 on the relay to ground, aka I wrapped a wire around the leg of terminal 85 plug the relay back in and grounded it, fan engages no issues. I'd like to be able to switch this functionality, I have a spare relay on my block available, I can have my switch engage this relay to supply ground to terminal 85 on the cooling fan relay, the problem being I can't get the PDC out to figure out which wire on the harness is terminal 85 for the cooling fan relay.
Anybody have a wiring diagram of the PDC of a 91 4.0L HO Cherokee?
It's the early style with the relays all on one long row. Relay 1 closest to the firewall is the cooling fan.
Anybody have a wiring diagram of the PDC of a 91 4.0L HO Cherokee?
It's the early style with the relays all on one long row. Relay 1 closest to the firewall is the cooling fan.
Last edited by at05gt; 12-31-2015 at 11:18 AM.
#23
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Year: 1991
Model: Cherokee
Engine: 4.0L HO
Brown and Purple Santa's should be dropping off my Autopal H4 housings w/ bulbs, and my new temp sensor, today.
I've also got new front end parts coming in to repair the superficial damage caused by my wife's accident 3 years ago, she owned the Jeep before we got married and I took it over when she got a new car. New header panel, headlight surrounds, new grille, and new side marker lights.
I've also got new front end parts coming in to repair the superficial damage caused by my wife's accident 3 years ago, she owned the Jeep before we got married and I took it over when she got a new car. New header panel, headlight surrounds, new grille, and new side marker lights.
#27
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Year: 1991
Model: Cherokee
Engine: 4.0L HO
So the half price temp sensor I ordered arrived DOA, caused the fan to run constantly and threw a check engine light, code 22 (cooling sensor and wiring). So I went and purchased a new one at the parts store for 15 bucks and this one works................. that's what I get for trying to save money.
On a happier note the Autopal headlights I ordered installed with no issues and are super flippin bright, illuminates the road so much nicer and has a sharp cutoff so I don't blind anyone. My old sealed beams where tiny pinpoints of light and these light up the road like a battlefield.
On a happier note the Autopal headlights I ordered installed with no issues and are super flippin bright, illuminates the road so much nicer and has a sharp cutoff so I don't blind anyone. My old sealed beams where tiny pinpoints of light and these light up the road like a battlefield.
#28
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Year: 1994 SE
Model: Cherokee
Engine: 4.0
Coming along nicely. Tell me about the panel that all the switches are mounted on please. I was thinking of doing something similar, want it to be as clean as yours.
#30
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Year: 1991
Model: Cherokee
Engine: 4.0L HO