Question about 1991 Jeep Wrangler

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How much does it cost to do a valve job on a 1990 4cyl jeep wrangler

3 & 4 cylinders are not firing spark good fuel good what do I check next

Posted by Frank Demartini on


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Allison Hayes

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Really depending on how far you want to go as you will need a vrs kit that will be over a hundred and then it all depends on damage done , to hard to be accurate with out the head being removed, crack tested valve seats coupled , surface grind. bit of specialist machineing involved . and other things cropped up like valve stem wear etc . hope that gives you a bit more of a idea

Posted on Sep 19, 2014


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SOURCE: #3 cylinder miss firing--2001 jeep g.c. larado

check from the spark plug back...

Posted on Mar 17, 2009



  • 30 Answers

SOURCE: 98 jeep wrangler 2.5L #4 misfire

check fuel for pressur and quantati to fuel rail posable fuel pump or regulator

Posted on Jun 09, 2009

paul campbell

  • 1071 Answers

SOURCE: 03 JEEP wrangler Rubicon 4.0L missfire on cylinders 1,2, and 3!

bad fuel pump can cause this or plugged fuel filter but i believe they are one unit

Posted on Jul 30, 2009


  • 25 Answers

SOURCE: gas gauge is stuck on half full, 92 jeep wrangler

check your flotter usually located under the rear seat

Posted on Oct 04, 2009


  • 30 Answers

SOURCE: Jeep won't start

we had a jeep with similar conditions at my college and we found it to be the crank sensor and it started and continued to run so test the connection and see if there is 5 volts going to the sensor

Posted on Mar 03, 2010

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My 92 jeep cherokee sport won't start getting fire and gas and has a slight back fire when turning over changed cranking sensor but still will not start what else could cause this?

old old jeeps..... which engine, the 4.0L inline 6? why not say ?
well here are the proper linear steps.
1: fuses good battery charged, and cranks robustly.
2: compression over 150psi, WOT. if not fix that. ?
3: spark strong to all cylinders not just 1.?
4: spark timing check show its still firing near 0 TDC.
5: at the point in time, it will run on test fuel for at least 3 seconds.
does it, feel better now? that you can see it run?
if not the CAT may be melted and blocking engine exhaust 100%
6; and last is fueling (the ECU cuts fuel or 3 reasons, )
dead cam/crank sensors, or dead tacho line.
7: ok check fuel pressure next.

i skipped the all important scantool because we dont have one
1988 to 92.. (not until 1993 do they work OTC tools)

did you do the magic key on off test>/
keyon 3 times, might work on latter 92s.....

the crank sensor is tricky to replace.
its not just jammed in a hole.
did you read the FSM Book first. before touching it.
some have a paper sticky tape on the end (jeeps do)
and when you start car first time, the tape flies off getting that critical gap correct. (pure magic no?)
if not done right, you now have 2 problems.... not good that.

Sep 28, 2015 | Jeep Cars & Trucks

1 Answer

My Opel kadette has no power and backfires when I over rev it refuses to go up any hills and has a continues miss fire

It sounds like your firing order is out or your timing is out or you have fuel starvation.
I believe the firing order is 1-3-4-2 on your car. Only English Fords had a firing order of 1-2-4-3 and VW beetles are 1-4-3-2.
Next. check the timing. You should have a spark on no 1 cylinder when the timing mark on the front pulley is about 16 degrees from top dead center - there is a mark on the pulley to show these positions. If you don't know how to check it, take it to a service agent.
Make sure your fuel filter is clean - replace it, they are cheap - and then make sure you have good fuel flow to the carburetor.
Finally, you could have burnt valves. This will mean taking off the cylinder head and reseating or even replacing burnt valves. This could be a costly job and should be done by a qualified technician.

Mar 12, 2015 | Opel Kadett Cars & Trucks

1 Answer

Jeep will crank but not fire, check engine light will not come on so I can get codes.

Need to check spark and fuel start by picking up a tester for the wires it plugs in like a spark plug and has a light that will come on if you have spark the next disconnect the main fuel line to the fuel rail and turn the key to the on position if u get fuel out of it the the pump is good

Jan 27, 2014 | 1997 Jeep Wrangler

2 Answers

Rough idle on 1989 4.0, smooths up at drive speeds. What do I need to check?

Start by checking spark plugs, if only one of your spark plugs are not in optimal conditions your cylinder will miss fire causing the rough idle.

Dec 28, 2009 | 1989 Jeep Wrangler

1 Answer

95 jeep wrangler making tractor/old tyme car sound

It sounds like you have a bad valve or a cylinder isn't firing. Pull the spark plugs and check them for deposits and clean, regap or replace. Do a compression check of the cylinders to determine if you have a problem with a valve.

Nov 30, 2009 | 1995 Jeep Wrangler

2 Answers

Wrangler 4 cylinder working on 3 cylinder what

You need to find out if you have spark there, if injector is working and if the cylinder itself has good compression. Then, you can work backwards to find out why whatever is "missing" isn't there.

Aug 27, 2009 | 1998 Jeep Wrangler

2 Answers

03 JEEP wrangler Rubicon 4.0L missfire on cylinders 1,2, and 3!

bad fuel pump can cause this or plugged fuel filter but i believe they are one unit

Jul 30, 2009 | 1998 Jeep Wrangler

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