20 Most Recent 1991 Jeep Comanche Questions & Answers

When the problem is ongoing, check the basics. Make sure battery has full charge. When the problem is ongoing if it cranks good but won't start, Have a helper crank it while you check for spark at the plugs. If spark everywhere, use a gage and check proper fuel pressure. Also, check fuel injector pulse. Trying to find what is missing, fuel--spark--whatever. I can only help with testing, you have to do the testing.

i sold my 91. but what is a vacuum seal, where is it, what system, (engine ,tranny, or transfer case?) what cable. im at a loss....?????????????

is this not the RENIX injection, french? 88-91 I had 2 , 88s, and know it well. too well, would like to forget it..... 93 is best old year. no Renix thank almighty rule 1: renix, ends. 1991 - Chrysler Corporation (then the owners of the Jeep brand replaced the Renix control system with OBD-I-compliant control electronics, the Chrysler HO EFI). a blessing as scan tools now work. same as Cherokee which engine the 4 liter, I-6 or the 2.5L? diagram. of what,? physical lay out.? fuel side.? electrical, ? all? the FSM covers this, all of it. and on mine the I6 has its own book. try alldata.com, log in and read. then ask questions. no posted symptoms. 1: runs bad???? 2; got the engine in basket, 3: got car and engine in 3000 pieces.? (done many like this) 4: all this was removed, and want to put it back.? here it is, if you need bigger , i cant help because FIXYA has no PM mail systems to send you a large photo. so here is the electrics, this what you want. alldata.com has it. log in.

no , but if in limp home mode (ECU) yes. if the cel is out , running its not in limphome.my guess? car was never tuned up, in last 60,000 miles or ever.i had a 91 Comanche and ran it 250,000 miles, (5speed)classic fails:the bottom exh tube under my bell housing , the clamp breaks every 6 months ( i welded up a life time clamp) this allowed theexhaust down tube, to flex and whole exhaust to act as silly pendulum. this put stress on my SST headers causing crackes.this in turn let fresh air suck in to the header and slam the oxygen sensor to the rails, (car ran rich a s pig and could not keeps spark plugs clean.) also the 91 has recalls on the CKP sensor. causing misfires.its on the top left top of bell housing, very hard to see.there is no scan tools for this Renix system. so can pull scan DTC codes, is your CEL glowing running?, BINGO.my 99 Cherokee had none of this (well except sloshing fuel starves the fuel pump at 1/4 tank, design flaw.)sputter is misfire.the 91 does not have misfire detection in the ECU,not till 1996.so you are the detector.do a full tune up.then look at spark tips.are the cream color or black.????????????if black, post back.i still miss and loved my Comanche. (im 1/8 real Comanche blood)

The factory aluminum wheels on Jeeps tend to become fused to the rotor and drum surfaces. A lot of can spray rust remover and a lot of tire kicking, after removing all the lug nuts, that will loosen up the bond between the wheel and rotor surface and the wheels will start to come off eventually, lots of kicking, alternating between the top and bottom of the tire.

yes,bad gas could but it sounds like you have one or two cyl. not firing check the spark plugs and wires how long since last t-up

Try googling fuse box diagram and select images usually a good source or autozone online

remove the cylinder head and drop the oil pan but if the rod is bad the crankshaft is most likely damaged so pull the pan and look at it first

Put the truck on service ramps or a lift. Pump out any fuel in the tank. Remove the plastic cover from the tank straps, 10mm socket. Unhook filler and vent hoses. Unhook fuel lines, electrical wires and vacuum lines at the T connector.Support the tank with a jack and loosen the strap nuts with a 15 mm wrench, then lift the strap hooks out of the notch in the frame. Once loose, work the tank out. Dropping the drive shaft would make it easier.

Okay, Ill share what I got with you. The information I have is gleaned from '94 & "95 Jeep

In side will be the line coming from the fuel pump.

Its a 91,,,,20 years of use on that fuel pump, If it is not getting gas than its the fuel pump, You could try replaceing the fuel filter,And have some one do a fuel pressure test,But its most likely the pump died and yes some will pump a little and than quit.How many miles on it? thats how many miles on that pump also.

you need to check the following parts related for ignition, 1) check the terminal of your battery, 2) check your fuel pump, 3) check your starter and 4) ignition switch...after you check all those parts, i'm hoping you can locate the problem of your vehicle...goodluck

Check your transmission fluid level. The fluid could be low. This will cause the car to slow down especially going up hills.

Since there are a total of about seven of those in your vehicle, The general method of removal is to remove whichever part (drive axle or driveshaft) the universal is in. Once out, there is a "c" clip on the inside part next to the rubber boot that needs to be pried out. (look at the new one and you will see a groove in the joint cap and the new clips in a bag....that gives you an idea as to what they look like and where they are). If you don't remove them you will damage the shaft.
There are a few ways to get the cross off the part. The proper way though is to get (rent or borrow) a hand held press, from one of the larger parts stores. Press the old one out and press the new one in. You can also drive them out with a hammer and a vise but unless you support it correctly and only hammer where it is safe to do so I would not.
Most important part is grease....it is difficult to put lube into universals once assembled. use a high quality synthetic or marine grease and make sure each cap and the cross are well lubricated. Too much will just squish out so don't worry about it.
If you do any off-roading it is essential to put the grease fitting in a position where as the driveshaft turns that area is "loaded" in compression, (driven yoke turning towards the fitting not pulling away from it) not unloaded, where it will want to tear apart.. If just street driven, don't worry about that.
During assembly, pay close attention to the rollers inside the cap. Do not let any fall down or you will not be able to get the cap all the way on.
It also helps if you drive the first cap in a bit too far to replace the lock clip, then compress the other side. Some lock clips are a bit too thick and you may need to sand one side down a bit to get it in. (check thickness of new ones against the old ones to see if that's necessary.
If the universal that needs to be replaced is the rear of the front driveshaft (double cardan joint) have someone that has done those before either do it or help you do it...(a bit more complicated)

Put an OBD1 scanner on it and clear the maint light. Comes on at 60,000 and other mileage as a reminder.

judy Goodmorning this is Bill from fix-it. you dont mention what engine we are working with,this would help in my diagnostics.Need to know what the fuel pressure reads ,I suspect by the things you say it is doing a clogged converter,but need to know what engine and then i can give you more info.Also to check the converter you can loosen the exhaust at the y pipe and if it runs better you have isolated problem.You may need to soak the y-pipe bolts with penetrating oil for a while to keep from breaking them on this old of a vechicle.

Especially with noises, it's nearly impossible to diagnose without being there. The noise you are hearing may be the first indication of your catalytic converter beginning to fail. As the exhaust gets squeezed through a smaller and smaller opening it can make that kind of noise. If the engine is running rough at idle, I'd also check for vacuum leaks.