MJ Comanche Tech. Stock & Modified. MJ (86-92)
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Comanche Distributer help needed

Old 05-16-2017, 11:47 AM
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Default Comanche Distributer help needed

Hi there, i'm having a pretty hard time getting my comanche to run after putting in a new distributer & i'm wondering if anyone might have any advice.


It's a 1991 comanche with what i have been told is a engine(inline 6) & automatic transmission out of a 1998 grand cherokee. (I checked the part number of the distributer that came off & it's listed as one for a comanche)

I've had the truck about a year and it's always been really great & reliable. Recently though i started noticing that after the truck was good and hot it wouldnt idle great & then most recently shut off & wouldnt come back on for a while. After testing out a few things i concluded that the pickup in the distributer cap was going bad when the truck was hot. I decided to just replace the whole distributer, after marking placement of the old distributer i pulled it & placed in my new one in the same fashion. I went to start the truck & i got nothing, the motor just spun over without ever actually firing. I wasnt to worried & decided that i would just set the distributer up as if i hadnt marked the old one.

I brought cylinder 1 to TDC on the compression stroke and then lined up the distributer with the piece inside the cap pointing towards the number one spark plug wire (as the manual indicates) the truck still would not fire, i then proceeded to to try setting the distributer in every position i could find anyone suggest on the forms. (every time bringing cyl 1 back to TDC on compression) i did end up finding a position where the truck would run but it's only firing on a few cylinders.

I'm a motorcycle mechanic working mostly on older bikes running points ignition systems & new electronic systems to replace the points, and i'm very familiar with setting timing on those, but something about this truck is kicking my butt & i would love any advice y'all may have.

I'm wondering if the previous owner could have done something to retard or advance the timing? Or am i just missing a step in installing the distributer?

(Also all plug wires are going to the correct points on the cap, i'm always getting spark, motor compression is good, and the fuel pump is working with good pressure)

thanks for any help!

-Micah

Last edited by micahbearden; 05-16-2017 at 11:51 AM.
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Old 05-16-2017, 12:00 PM
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Nice work getting an MJ with the high output engine, if that's the case. However, I don't think a 1986-1992 (Comanche era) distributor will work with an OBD-II (1998 GrandCherokee) ignition system. You might look into whether you should be replacing the old dizzy with one specifically for that engine, not the Comanche.


The timing is controlled by your crankshaft position sensor, which sits bolted to the bellhousing at the back of the engine bay. The sensor's holes can be drilled to shift it forward or backward on the bellhousing to advance or retard the timing. But again, that's on pre-OBD-II vehicles- newer systems would compensate. Worth a peek nonetheless.
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Old 05-16-2017, 08:51 PM
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PM sent - hope it helps.
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Old 05-26-2017, 07:49 AM
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Originally Posted by alpine.adrenaline View Post
Nice work getting an MJ with the high output engine, if that's the case. However, I don't think a 1986-1992 (Comanche era) distributor will work with an OBD-II (1998 GrandCherokee) ignition system. You might look into whether you should be replacing the old dizzy with one specifically for that engine, not the Comanche.


The timing is controlled by your crankshaft position sensor, which sits bolted to the bellhousing at the back of the engine bay. The sensor's holes can be drilled to shift it forward or backward on the bellhousing to advance or retard the timing. But again, that's on pre-OBD-II vehicles- newer systems would compensate. Worth a peek nonetheless.
If it was already running and he replaced the distributor with one that plugs in, it should work fine.

Here's the real definition of HO:

HO myth buster


Renix in 90 made 182 HP. HO in 91 made 190 HP. That's 8 HP difference.

HO only made more HP than Renix at higher RPMs and not a bit more torque. HO had a 58 mm throttle body versus a 52 mm throttle body on a Renix. That’s 20% more air available through the HO throttle body. The HO also had a better design header. See where I'm going with this?

It’s only a 4% horsepower increase…..

The whole 8HP was not mostly from the head, but from the bigger TB and better exhaust manifold.

Put a 60mm TB from www.strokedjeep.com on your present manifold using the Renix head, eliminate the "crush" in your headpipe with proper re-routing, and go for it.

HO stands for Highly Overrated.
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Old 05-27-2017, 06:52 AM
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Sounds like its not clocked correctly. Was cap just pulled with wire still attached then reinstalled ? Theres two different firing orders ones correct one is not if wires were removed. Note dist cap screws....
Attached Thumbnails Comanche Distributer help needed-91718.jpg  

Last edited by freegdr; 05-27-2017 at 06:57 AM.
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Old 05-27-2017, 07:05 AM
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