I wonder how that photo was taken. It must have been a cut=away.

I love your statement ""R*C*B*R*C= Refresh Connections Before Replacing Components.
That needs to be tatoo'd inside lots of eyelids!

 

I can't remember who I stole that photo from. Pretty cool.

 

Update: I drilled out the upper hole on the CPS bracket. The bracket is resting against the lip of the bell housing so, it's as close as it's going to get. It made a slight improvement to .2. I also pulled the plugs, they were black with carbon build up, so I cleaned them all up. Is the CPS from Napa or the dealer modified already with a slotted hole? I'm not sure why the sensor I'm using has a weak signal but I guess it happens.

 

The one with the slotted hole was the one included in the "patch harness" from Jeep.

 

Read this and then do it.

Renix Jeep C101 Connector Refreshing
　
The C101 connector on 1987 and 1988 Renix Jeeps was a source of electrical resistance when the vehicles were new. So much so that the factory eliminated this connector in the 1989 and 1990 models. The factory recommended cleaning this connector to insure the proper voltage and ground signals between the ECU and the fuel injection sensors. We can only imagine how this connector has become a larger source of voltage loss and increased resistance over a period of almost 25 years. The C101 connector needs to be cleaned at least once in the lifetime of your vehicle. Chances are it’s never been done before.

Almost every critical signal between the engine sensors, injectors, ECU, and some to the TCU, travel this path through the C101 connector.
The C101 connector is located on the driver’s side firewall above and behind the brake booster. It is held together with a single bolt in it’s center. To get the connectors apart, simply remove the bolt and pull the halves apart. You will find the connector is packed with a black tar like substance which has hardened over time.
Take a pocket screwdriver or the like and scrape out all the tar crap you can. Follow up by spraying out both connector halves with brake cleaner and then swabbing out the remainder of the tar. Repeat this procedure until the tar is totally removed. This may require 3 or more repetitions. Wipe out the connectors after spraying with a soft cloth.
If you have a small pick or dental tool, tweak the female connectors on the one side so they grab the pins on the opposite side a bit tighter before bolting both halves back together.
　
Revised 07-17-2012

 

I've done the c101 connector, it's squeaky clean, as well as the ground refresher. I didn't get a chance to run it yet after I cleaned the plugs and modified the CPS due to a heater hose leak that side tracked me. I have to fix that tomorrow and run it and see what I got. I'll check back, Thanks!

 

A weak signal - it's just a magnet with a wire wrapped around it. If if's a cheapo it may not have as many turns around it, or the insulation is bad.
Or the the coil shorts to the magnet, grounding or reducing the signal. That's why it's important to buy quality parts.

No matter how good the CPS signal is, a weak spark won't light the fire! Again - QUALITY COUNTS!

 

Gottcha! One would think that such an important yet simple part would be made with quality no matter who the MFG is, but I guess I should know better. The research I've been doing all indicate that spark and CPS are related. Weak signal from CPS = weak spark, to the point where the engine will shut down, which is what is happening here. Is it your opinion that this is not the case? I want to be sure before I go buy another CPS.

 

Update: Heater hose fixed, I was able to run it. This is where I'm at:
I still have the modified Duralast CPS from auto zone installed which was improved from a .1 to a .2 signal. I cleaned all the plugs, they were black with carbon build up.
The jeep started quicker than normal, once it got a little warm, the RPM's krept up to about a grand on it's own. At that time I got in the jeep and revved it a little and it started hesitating again. About 2 minutes later the RPM's went back down to about 750 and it ran normal, idled fine and did not hesitate at all, nice an smooth. I ran it for about 10 more minutes and it ran fine and I shut ir down. I went back outside about 15 minutes later and it wouldn't fire up at all. I don't get it. I ordered the Napa CPS, I'll install that tomorrow and check back.. Am I on the right track?

 

Sounds like you may have multiple issues.

Get a good siganl out of the CPS. Don't be afraid to drill/slot the upper slot in the new cPS as needed.

Time to check your TPS on the engine side for issues.

 

The TPS was bad, I replaced it a couple months back. I recently tested it to double check- all good.

 

The coil gets it's signal and power to fire from the PCM - not the CPS. The CPS just triggers the PCM, telling it WHEN to fire the coil.

If the CPS signal is too weak, it won't trigger anything - no injectors, no spark. It's a threshold or "go or no go" situation.
Temp often does play a role - in both CPS and Coil.

Anything other than a crispy blue spark indicates the coil output voltage is too low, making it difficult to light the plug.
Either the 12 volts applied to the coil is not 12 volts, or the coil has an internal short - a popular failure. (Good to carry a spare!)

For some reason aftermarket coils are junk - even the so-called High Performance ones. Even ACCEL and MSD Jeep coils are junk. I've had to trash several. OEM's seem to last, but they go south at about 150,000 miles.

Try swapping it with a friends working coil. - easy - You don't have to ground it or bolt it in, just attach the connectors and coil wire.

It will prove it either way.

 

X2^. After you know your ECU is getting a good signal you can take it from there. My experience dove-tales with Cruisers info. Under .35 was the beginning of the end.

Cruiser's coil contact cleaning deal is there in my signature...I'm not going to re-read all 70, (so please forgive me if you have already been there!)

 

Thanks to all. I'll check back tomorrow after I modify and install the CPS. Hopefully I'll get a good signal so I can either rule it out or solve it.

 

This is true.