Cylinder misfire 98 4.0 180k - JeepForum.com
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post #1 of 19 Old 09-04-2019, 05:57 PM Thread Starter
ZJ_Jimmy
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Cylinder misfire 98 4.0 180k

Did a search but didn't find my answers

So late July, I replaced my crank position sensor on the side of the road. Ran fine for a while, But now I'm getting multiple cylinder misfire code. Originally on 6 then 5 and 6.

Replaced fuel pump and sending unit
Plugs, wires, cap and rotor.
All 6 fuel injectors
Map sensor

Now it's it's on cylinders 6 and 4.

The engine also has a nasty vibration from 1400 to 1600 rpm regardless of it being in PNRD.
Changed out the crank shaft pully problem still exists.

Any thoughts would be greatly appreciated

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post #2 of 19 Old 09-04-2019, 11:38 PM
rep-tile
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If it's not an OEM Mopar sensor, throw it in the trash.

04 WJ 4.0 - Avital 4103, DB-ALL
91 XJ 4.0 - Avital 4103, Stage-2 aFe intake system, BBK high flow Throttle Body, Jones Exhaust A3518M-5
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post #3 of 19 Old 09-05-2019, 05:27 AM
jtec
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I give this a try - 1998 4.0 ZK ?
the only codes are P0304 and p0306 and no other codes?
Suggest a SCANNER - scans are FREE at many auto part stores post all the codes.

PLugs- how did old plugs look esp #4 qnd #6? Wet, dry. black damaged?
You did use solid core plugs OR ? yeah it matters.
Why did you replace MAP ?
Why did you change crank pulley?

I am suspecting other codes - until then - chack for Vacuum leaks at intake esp the misfiring cylinders. Inspect #4 and #6 plug.
Is airbag light on?
Do you have a compression gauge and a vacuum gauge?

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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post #4 of 19 Old 09-06-2019, 09:17 AM Thread Starter
ZJ_Jimmy
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Codes are p0300, P0304, P0306

Crank shaft pulley was replaced as it was worn out, these pullies are pressed together with a thin piece of rubber between these 2 sections.

I'm leaning towards the doorman crank position sensor failing.

I'm still baffled by the Vibration between 1400 and 1600 rpm.

Prior to this the jeep would accelerate in third gear pulling up a pass I drive every day to work.

Now with the pedal to the floor it barely holds speed at 60.

Thanks for your input guys
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post #5 of 19 Old 09-06-2019, 09:20 AM Thread Starter
ZJ_Jimmy
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Here's a picture of the #6 plug
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post #6 of 19 Old 09-07-2019, 01:26 PM
LouC
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Any antifreeze/water in cyls?
Also...Jeep 4.0s need the plain old Champion Copper Plus plugs...any of the high tech plugs do not run right in them...what are those? Don't look like Champion Coppers.

2017 JK Unlimited Sport 6 spd
2007 WK Limited Hemi QDII
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post #7 of 19 Old 09-08-2019, 09:55 AM Thread Starter
ZJ_Jimmy
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I put in NGKs 7525,. There's no water in the oil,
The jeep runs, but it's off.

Any chance the computer might be stuck at a specific run frame and that's why it's not making any power?

I do know these things have adaptive learning, thinking the computer has lost its run memory and can't re learn?
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post #8 of 19 Old 09-08-2019, 10:28 AM
jtec
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Lets back burner the PCM concerns right now,

I am no fan of platinum esp fine wire type. My 2

That plug looks OFF (not right) an I also ask about coolant system - are you using loosing coolant?
with plugs out - when grounded do they spark as eng cranks to start ?

Fuel pressures using a gauge.
ENgine is reaching temp @220Deg F ?
Vacuum reading.
then a compression check -

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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post #9 of 19 Old 09-08-2019, 12:12 PM
RedRiverT
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Intake manifold gasket leak, vacuum leak, cracked head . . . something is wrong at 5 & 6. That #6 plug doesn't look right. Pull them all and compare. Your nasty vibration is most likely because 5 & 6 aren't working right.
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post #10 of 19 Old 09-08-2019, 11:17 PM
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Get rid of the dorman sensor and the v-power plugs. Then reset the computer (unplug the battery).

You can use Champion or NGK, but make sure they are copper core plugs. Here is the warning regarding using the wrong type of plug they found necessary to put out about twenty times throughout WJ manuals .
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04 WJ 4.0 - Avital 4103, DB-ALL
91 XJ 4.0 - Avital 4103, Stage-2 aFe intake system, BBK high flow Throttle Body, Jones Exhaust A3518M-5
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post #11 of 19 Old 09-09-2019, 08:43 AM
LouC
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just for the heck of it I looked up that NGK # and they are SUPPOSED to be copper core plugs...but that one does not LOOK like a copper core plug!

2017 JK Unlimited Sport 6 spd
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post #12 of 19 Old 09-09-2019, 04:32 PM Thread Starter
ZJ_Jimmy
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How I checked for vacuum leaks was by way of starting fluid sprayed all around intake manifold and vacuum lines. No change in engine RPM.

The old plugs were auto light here's I got a picture of #6 and #1.

As for losing/ using coolant, o have not noticed any level change in the reservoir. Nor does the exhuast smell sweet. And there are no drips or puddles u see the Jeep.

My understanding is that the cam sensor tells the injector when to fire, the crank sensor tells when to spark.

U see normal drive conditions I go to pull a hill and if feels as if the spark is not advancing enough to keep up with engine speed. But then again. I guess it could be that it's not putting enough fuel into the engine either.
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IMG_20190823_160022_01_1568068048266.jpg   IMG_20190823_161240_01_1568068083545.jpg  
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post #13 of 19 Old 09-09-2019, 11:32 PM
RedRiverT
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I figure that the top picture is #1 plug and the bottom picture is #6, since it is orange/rusty like the earlier picture of #6.

The gray plug looks right. I don't see how the problem could be fuel or anything common to all the cylinders since the plugs look so different. I assume #5 will look like #6.

"My understanding is that the cam sensor tells the injector when to fire, the crank sensor tells when to spark."
I guess the exact way to say it is that the cam sensor tells the PCM what the valve position is, then the PCM fires the injectors according to its program, and the crank sensor tells the PCM the piston position, then it triggers the coil. Of course, the "cam sensor" is actually on the distributor shaft, so I'm guessing as the gears wear, the signal gets later. I don't think there is any fancy-schmancy compensation for wear.
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post #14 of 19 Old 09-10-2019, 10:19 AM Thread Starter
ZJ_Jimmy
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Up date,

CEL returned again, misfire on cylinder #2 and #4 this time.

Drove to work, there was a 5 mile stretch where it had good power, felt like everything was normal.

Cod it possibly be a ground?
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post #15 of 19 Old 09-10-2019, 10:28 AM
igorhandsome
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Have you replaced the Dorman CPS with a Mopar one as already suggested?
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