Don, without looking back, didn't you suggest that I test the MAP with the 02 sensor unplugged? Should I still do that?

 

No. I was suggesting, (and still do), that you try running it with the 02 disconnected to see if that affects your pig-rich condition. (if you still have that). I'm pretty sure without it, (the 02), it should run OK. Rich, poor mileage, but OK. I only suggest unplugging it cauz it's so easy. I'm not thinking the 02 can make it blow black smoke. (I'd be happy to be dead wrong though!)

The MAP is independent of that. Has a ground, and that 5 Volt feed from the ECU Easy to check those., THEN it has it's output to the ECU from the middle. Tougher one to check there.

This is short and not so complicated... A digital meter takes a reading every so often. If the voltage is moving, it's "snap shots" can just display gibberish on a digital. An analogue meter with a needle will show a "sweep" of voltage from higher to lower. If your problem is not resolved elsewhere, you might come back to that. (the Map>to ECU voltage "sweeps")

I've been PM'ing with CPT, on a roughly similar problem he had with mice eating his Coolant Temprature Sensor wires. (in regard to your problem) He reports that when it was screwing up, (one wire not connected), it would go rich right away......Anyway, both he and I had real trouble just cuz the wire gang off the injector harness down to the lower sensors had a problem. I think he needed to split the loom to actually find his bad wires.

Mine was right under my nose for about a year before I found it! (also hidden by the casing on the wiring). When it got hot the heat shield would expand and ground some wires. Now I wish I would have checked which ones before I moved and repaired it. It doesn't even belong there by the exhaust, (PO took it to "Pros")

Good thing you are not stranded at a truck-stop or something! (your cholesterol would be off the chart by now)

If I remember right, CPT needed to leave his CTS unplugged, so he could use his Jeep, (while he tried numerous sensors), before he found the bad wire. (I don't get that)(opening an open?)(by unplugging it)

 

I thought the coil was the issue. What happened with that?

 

Your sharp as a tack....the thumb end.

 

Turning on the Ign, unplugging the map connector and verifying that there is 5 volts on the passenger side connector should only take a minute.

Also I'd want to check that air cleaner element.

 

Richness can be caused by these three sensor in this order: MAP, CTS, IAT. Perhaps wiggling the harness while idling will pick up an intermittent connection to one of those sensors?

 

GOOD! You finally got around to swapping the coil. You said it ran the same.
Does that mean if ran fine like it sometimes does, or terrible like sometimes?
With the other coil - what was the color of the spark? Still white like before? If yes then that shows where the problem probably is.

There are several things that can lower the coil voltage, changing the color, the most common one is a defective coil, but not the only one..
And - tell us how you are testing the spark for color? That too can lead to the problem.
I still suspect it's an ignition problem - it's just not getting a good fire started.

One problem with this - if the ignition is weak, it can foul a plug, then even with a good spark from a good coil the fouled plug still makes it run terrible. THE COLOR OF THE SPARK AT THE PLUG WILL TELL YOU HOW STRONG THE IGNITION IS - NO MATTER HOW IT RUNS!

You said it's "dumping fuel" -- but it holds pressure when shut off - eliminating a mechanical problem with an injector. And, if I remember right, fuel pressure is normal.
In order to "dump fuel" it has to have a command from the PCM to open he injectors too long. Injection time needs to be looked at - before blaming sensors and other things.
Attach a noid light o an injector - you can buy the right one at a decent parts house for less than $10. Look in the HELP line of parts. You don't need the entire kit.

Run it - see how it looks when it's running fine - compare when it's not running fine. If it's truly dumping fuel, the noid light will be on longer and brighter.

Seems you said it runs bad at initial start-up - cold, and fully warmed up, and even will not start sometimes.

The start and run cold - the O2 sensor is not used,, it essentially only uses the TPS and MAP as inputs. Other sensors don't have an immediate influence.
But - IGNITION always runs.

 

Here is a theory, let me know what you guys think.. Could I have a leak in the intake manifold gasket or TB gasket, when it heats up, it opens and sucks air, the o2 sensor is signaling for more fuel, the ECU cannot keep up with it so it cycles to where it runs crazy rich and back to normal?

 

Spray around the throttle body and intake gasket when you suspect it. That will answer your question. I thought the coil was the issue.

 

My .02, that's just something any of us could check anytime. Those bolts do loosen. Also vacuum leaks do happen. On your theory of the leak getting worse...if the manifold vacuum dropped because of a leak, guess what? The MAP would dump more gas, thinking it dropped because you opened the throttle plate with your foot.

I see in Pete's C-101 connector writeup, he mentions tightening the female clips with a dental tool. Being that we are all having sooo much fun here...(glad you are not stranded!)...OK here's a thought. Just remove that one bolt and take a look in there, the C-101. See what you see. Then work it on and off a few times, then run it and see if there is any change. Shouldn't take 10 minutes and just might be helpful. I do know you cleaned it, but one little wire connection might be your problem.

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Vacuum leaks suck. I go around with short little shots of starting fluid, if you hit one the sound of the engine will change. Small little shots! You don't want that stuff to accumulate. It's a fire hazard, but It evaporates right away. Also with a tube, or a section of hose you can listen for it. Don't forget the lower O rings on the injectors need to seal as well. (uppers would leak fuel).
The manifold bolts have a habit of loosening, especially that rear one. On anything like that you never want to tighten only one. It can warp/bend, even crack things. If I found that any that where easy to reach where loose, I'd pull the air cleaner and tighten them all, starting in the middle and working out towards the ends. I go over about three times. It's a bear of a spot to get a torque wrench on them all. Just don't ape on it. If its firm and not turning, no point in going on to break it, a REAL *****. The rearmost bolt underneath takes a little doing, but it can be done with the right extension. For that very back one by the firewall I use way long extensions (18"), with a swivel at the socket. Anyway, that's a good thing to check on any old Jeep.

 

Sounds good.. I'll get to work on this, and the previous things mentioned Friday night.. I might get a little side tracked on Saturday, my explorer needs ball joints.. can't wait for that.
It'll be a nice change tho.. no volt meter!!!!

 

Oh yea, the wires coming off the injectors on mine is not the same as the photo you posted. Mine are on the other side of the regulator and go through that way. There are bare wires touching metal also due to a gap in the plastic casing.. I'm going to tape them up.

 

How 'bout a picture of it - the entire Jeep.
Since you don't want to fix it, but rather make wild irrelevant guesses spinning your wheels, maybe someone will buy it.

I'll give you $300 if it looks good - you pay shipping to So California.

Based on your symptoms it'll only take a few minutes to put it right. I'm low on Cherokee inventory at the moment. Even though it's a Renault/Bendix in a Rambler/Hudson body it will bring $1000 - but it has to run.

 

WHAT! Holly bingo batman. Yea, mine were routed wrong. Btw....sometimes I wouldn't turn it off all day because it was when it was parked that the heat would migrate to that shield, then expand it into the wires. It fired the mouse nest in the air cleaner fight out the front grille, drove through the confetti! (no sign of the mouse)


Check/note the color codes before you tapem'

 

Well, in my opinion, when you test something it either passes the test or it doesn't, that takes the guesswork out of it. If it passes the test you move on to something else, nothing is irrelevant at this point until I know what it is. Eventually, sooner or later if I don't find the glitch, I will make my way to the ignition.