OK, so i got a chance to work on the MJ today. After putting in my XJ bucket seats, I got to work on the engine again.
First i performed the ground and connector cleanups per cruisers posts.
Then I decided to take another look at the injectors. When i put the new ones in I noticed someone had pulled a bunch of the wires out of the loom and it was a mess. Someone has been all through this thing and done a half *** job. So of course when i put it back i cleaned everything up. I decided to check the injector wires, so i pulled up a diagram off th enet and it said the wires should be blu grn tan yel wht brwn from #1 back. Mine had 1 and 2 then 3 and 4 crossed. I thought AH-HA, abd crossed them back and went for a test spin. The jeep ran just a little smoother, but still no fix. It still has a miss/shake to it.
Then i went on the the CPS test per cruisers post. It says the CPS should read .5 AC volts? correct cruiser? The CPS that is on it looks like it was replaced within the last year or two, it looks kinda new. And it is reading .28 . Could this cause what I am experiencing? It also has massive oil/ATF/power steering leaks which I have not addressed yet and the bellhousing is nast coated. Could a possible rear main leak cause the CPS to get to nasty to function correctly? And if so, does this auto have an inspection plate somewhere where I maight could clean the flywheel off when I replace the CPS?
Thanks
Chad

 

You could do the drill mod on the CPS so it generates a stronger signal. Couldn't hurt.

 

Should I do that or just get a new quality CPS from napa or somewhere? Or do both?
Also while messing around under there, I found a second unhooked connector coming from the loom near the rear injector. It comes out of the loom at the same place the manifold temp sensor wire comes out. The funny thing is it is identicle to the other pluc which the CPS is plugged to, even the same color wires. (purple/white stripe - white/blk stripe). The connector that it has been hooked up to does not go into a loom, but the two wires go into the firewall through a small grommet by themselves. Has this thing had an engine swap with a different year wire harness? Is it plugged into the correct plug? What does the empty plug from the loom go to?

 

I know what happened. Your Jeep had the dealer CPS bypass done and the goon left the old CPS connector there. They were supposed to tape it back into the harness.

Up to you on CPS. You could just do the drill mod on this one or on a new one.

 

Oh! Wow you da man!
I ran outta time for the day, but this weekend I will try the mod before I buy a new one. I will put some more time in on it this weekend.
I am really shocked at how little of a difference it made to swap those injector wires around. I am still suspicious of those injectors firing properly under load. It is idling better, but still shakes with it in drive and the brakes on.

 

Wiggle the injector connectors at idle.

Have you done the sensor ground test?

 

Hey! A chance to post my Golf deal..

LITTLE BALL, LONG GREEN, TEE YOUR WHITE BALL..................................

Light Blue, Light Green, , Tan, Yellow, White, then Black are the injector wire color codes.
If you know the pair in the middle is right, you only need to check one on each end.

I think it runs about OK because the fuel is still there for the cylinders, just a fraction of a second different timing.

I was watching, (and learning about), CPS AC voltage as mine dropped below .3 and started messing up. I might have done the mod, but the insulation on the wires right at/into the CPS was dissolving.

Further info/(trivia!) , on the mod for 87-88 with a C-101 > CPS & Harness bypass there http://www.bc4x4.com/faqs/yj.cfm?cat=5&faqid=164

 

To change your CPS I found if you BACK the fronts onto ramps, you won't have them in the way, where you need to lay. A stand under the left front frame would be in your way.

If CPS itself is putting out less than .35 Volts AC, unplugged, while it's cranking with a good battery, or the resistance is not 200 ohm's plus/minus 75, hot;

11mm socket > 3 inch extension > universal > long (18-24 inches of extension). Your feet are sticking out under the passenger side, you can reach up past the front drive-line with your left hand to hold the CPS from the front. Your right hand is on the ratchet way back by the tranny cross member. If you tie a long string on the old, you can use it to haul up the new. Toss that piece of plastic if it's still there, and do not drop the bolts in there! Echlin # CSS980, (from Napa, for 87-90), should be fine, but some prefer to go to Jeep. I wouldn't bother with anything else for that.

If your left forearm is bigger than a quart Mason jar, you might consider removing the front drive-line. Also You might cut your old CPS wires if they go through a deal on a bell housing bolt, then be sure your new are held somewhere safe.

The second one is REALLY easy!

 

The funny thing is the CPS looks almost new. Maybe it is just a cheapo? I will try the mod tomoro hopefully. If that doesn't work I guess I will be headed to NAPA for a new one.

 

I suppose all that really matters is that the ECU is seeing more than... .35 ACV from it. We are lucky, 91>on HO owners have a much more difficult test that takes a very spendy meter or a scope. Easy enough for us Renix owners to rule that trickster out of the equation...unless it only fails sometimes/hot.

I wouldn't mind carrying a spare. If the mod works, I still might buy one. I did save my last that had dissolved wires.

 

My exhaust had burned through mine, but would still work when cold. Then the AutoZone one only lasted 2 months before it had problems. The Napa one has been good to go for about 6 months.
I kept the AutoZone one as a spare though

 

Ok, I did the CPS mod tonight to get the CPS closer to the flywheel. I got .28 - .29 out of it. I guess I will be calling NAPA tomorrow. I wanted to do the timing advance trick on it, but the sensor was molded onto the mount and it would not slide on the mount without breaking. I am also going to re-check the TPS settings tomorrow as well.....

 

You can slide them even though they're molded on.

 

Well I put the new one from NAPA in today. No change. It registered .28 volts AC as well. I double checked the TPS and got the numbers pretty close there. I put a fuel pressure gauge and got 36-37 PSI. All seems well but it still runs like crap. I am pretty much done with it. I think it is just going to hafta miss until I can get a 5.3 or 5.7 to drop in it. Thanks for all the suggestions guys.

 

I'm at loss. That just aint right! (sorry Btw). That has to suck. Let's see what Cruiser thinks. I've read thay will actually run with (the wrong)>90 HO flex-plate. (with the gaps the CPS uses). .29 is just too low. That does not mean there isn't something else going on, but that CPS signal is the "hart-beat".