GosaGT1988

Well when money isn't an issue I'm going to go ahead and due a complete tune up on her. Ignition coil, ignition control module, spark plugs, ignition wires, well you know the list. She runs pretty damn good but I can't wait until I can afford to do the exhaust system. I'm going to do an oil change tomorrow.

Nevermind, just added some more transmission fluid and all good to go. Thanks a bunch for all the info. I don't know what I would've done without this site.

Florida might as well be a third world country. The stores around here are crap. The only place worth going to is either Wilson's 4X4 or Jeep Toy Box but they're a little more expensive than what I can afford.

Got the new CPS in and swapped in the old ICM, started right up. But now that I lowered my transmission (about 4 inches) to put the new one in and put everything back in it's place the transmission doesn't want to come out of first gear.

Got the old CPS off, that thing looks like hell. The wiring where the unit connects with the flywheel teeth is all cut up. I'm taking a little break before I put the new one on. I'm going to try the new CPS with the old ICM and see what happens. Like I said before, if the old ICM works I'm going to get my money back.

I'm going to have to do it tomorrow since it's already dark outside. I'm going to swap in the new CPS and try it with the old ignition control module. If the old one works I'm going to go get my $112 back from AutoZone for the thing. Thanks for the info on how to do it the easier way because that's a real tight spot for me to do it the way I was trying (reaching as best as I could trying each socket blindly.)

What's the easiest/best way to remove that DAMN CPS!!! i.e. what size socket, etc.

I used my ohmmeter and tested for continuity through the CPS. It should be somewhere close to 0. I got 0.25 which is close enough. But just for grins and giggles I'll give it a shot.

Checked the CPS that's fine. Ended up being the ignition module. Replaced it, lasted about twenty minutes of driving and crapped out, replaced that one, nothing. HOW MANY BAD MODULES CAN ONE PARTS STORE HAVE?!!!

I have never been a fan of ECUs. The one in my 89 YJ has been bypassed completely by the previous owner and I have no idea how they did it. The difference is that one has a carburator.

There's nothing wrong with it, I was just wondering. I am however trying to figure out a way to bypass that computer in there.

What all is necessary/needed to do it on a 4.0L in a 1990 Pioneer with the Renix system?

I went driving around with my Comanche earlier today and had no problems whatsoever. However, a few hours later I went to start up my Comanche and it just cranked and wouldn't start. I got out and tested the ignition wire coming from the ignition coil and there's no spark whatsoever. Could it be a bad ECM or ignition coil? It has a brand new cap and rotor, all new ignition wires, spark plugs, etc. I didn't go with anything except factory parts. I did not replace the ignition coil when I did all of this.

Yeah I do. I want to do a complete swap over.

I found a 1991 Cherokee in the junkyard and was thinking about taking out my renix 4.0 and putting in the Chrysler 4.0. What all do I need?

There's a trick to the possibility of gunk floating around. Use a less expensive brand motor oil, preferably 20W50, and then about a month after you do the flush, change your oil again using whatever you prefer. Any gunk that MAY be floating around will be gone. Trust me, I have 244,000 miles on my baby and after the flush I noticed a much better driving experience. I've used other brand motor flushes and followed the same procedure and never had any problems. I've owned nothing but Chrysler/Jeep/Dodge vehicles ever since I started driving and never experienced engine failure.

I just used Solder Seal Gunk High Mileage Motor Flush when I went to change my oil and I have to admit, that stuff works great. It costs about $3.00 - $4.00 but it's well worth it. READ the instructions carefully when doing so. I also decided to use 20W-50 motor oil after I did the flush. My engine has 244,000 miles on it and now it drives like a dream. I couldn't believe all the junk that came out when I drained my oil pan after using this stuff.

There's absolutely nothing wrong with my cylinder head. By what ya'll were saying, it would not mount up properly so I figured I would need the HO cylinder head. Well if the allignment issue is with the downpipe then there isn't an issue. I'm replacing the entire exhaust system anway. From the exhaust manifold all the way back to the tailpipe. So the downpipe alignment shouldn't be an issue right?

Unfortunately the cylinder head on the 4.0L HO was cracked, anyone know where I can find one? I was going to get both the cylinder head and exhaust manifold but you know.

Went to the local Pull-N-Save and found the exhaust manifold to a HO 4.0L. I'm going to put it on my engine (Non-HO). Luckily no cracks.

Did the compression test and got some pretty impressive numbers. From front cylinder to back I got: 130 - 135 - 140 - 141 - 135 - 137. I may have a bad spark plug or a bad fuel injector however. My 5th cylinder from the front is getting compression but it's burning extremely rich while the others are burning fine. I took the spark plug out and hooked up a spare spark plug to the ignition wire and tested it externally. It has spark, I got shocked so I know it has it, but I'm not sure of the one that's in there. I'm going to replace the spark plugs anyways with the Champions instead of the AutoLite ones. So basically I have a 5 cylinder engine for right now. I don't mess with fuel injectors whatsoever. I did notice however that my fuel injectors are kind of loose, how can I tighten them?

Which Ford Motorsports fuel injectors are you talking about? I have the I6 4.0L.

Apparently the previous owner slapped in the Dana 35 from a 1985 XJ into my 1990 MJ. The 1985 did not come with the c-clip but the factory 1990 MJ did. What do they mean by this and can it cause any problems?

Nevermind, I found it in the Haynes manual. The inline six should have anywhere between 120 to 150 psi with a maximum variation beween cylinders being 30 psi.

What are the spec compressions for the 4.0L? Mine has 243,000 miles on her, she still runs pretty damn good.