I figured out that the C in C101 stands for Chicken

[brucecooner]

cluck cluck...

I've done a few tips, but have been avoiding this one as "she runs okay-ish" and the thought of messing around with the vital and fragile C101 connector makes me nervous.

 

Then I had a crank-no-start condition the other day. 

I had washed some bird crap off the hood (dang pigeons are a menace) and was going to drive it a few miles to dry everything off. 

But it would crank and crank without starting.  

It was dark out and I was wondering if despite my caution with the hose I had gotten something important under the hood wet, so I went inside figuring I'd let it dry and try again.

The next day, same thing.

It had come back from the transmission shop a week prior so my first thought was that someone had disturbed the CPS in some way.

But upon raising the hood it was obvious the C101 was a little cocked out of place.

I tweaked and snugged it up a bit and and she started right away.  I guess it had wiggled out of place just enough...

I was just lucky it did this in the driveway.

 

Anyway, this is a clear message from the universe that it's time to bypass the crusty old C101.

Too bad my soldering skills aren't the greatest.  I know, practice...

 

There's an excellent video featuring the famous cruiser54 on yt detailing this process, but I was wondering...

 

Are there alternate connectors you can use that might idiot proof this process?   

 

Or is it just down to solder and oxgard and heat shrink tubing and patience?

 

[eaglescout526]

I just used electrical contact cleaner from Mopar and just blast the absolute ever lasting hell out of the C101. Anytime I have an issue, I spray that connector thanks to the grease inside getting warm and moving around. 
That being said, it’s not fragile, more sensitive to what you do if it’s not clean. Cleaning it out is an option as well. 

[cruiser54]

It's worth bypassing. But, have you cleaned it? 

[brucecooner]

7 hours ago, eaglescout526 said:

I just used electrical contact cleaner from Mopar and just blast the absolute ever lasting hell out of the C101. Anytime I have an issue, I spray that connector thanks to the grease inside getting warm and moving around. 
That being said, it’s not fragile, more sensitive to what you do if it’s not clean. Cleaning it out is an option as well. 

 

3 hours ago, cruiser54 said:

It's worth bypassing. But, have you cleaned it? 

 

I wasn't aware cleaning it was an option. 

My approach to it has been "don't disturb it" though I'm sure it shakes around plenty while I drive.

I have a can of the electronics cleaner stuff, I've hit some of the other stuff under the hood with it already.

I might just unplug the 101 and blast the contacts, then hope I can get it plugged back in.

 

[eaglescout526]

7 minutes ago, brucecooner said:

I might just unplug the 101 and blast the contacts, then hope I can get it plugged back in

Blast the hell out of it and itll plug back in just fine, a bolt is what keeps it in place while driving. Oh and put down a rag or something cause it will get very messy. 

[cruiser54]

7 hours ago, brucecooner said:

 

 

I wasn't aware cleaning it was an option. 

My approach to it has been "don't disturb it" though I'm sure it shakes around plenty while I drive.

I have a can of the electronics cleaner stuff, I've hit some of the other stuff under the hood with it already.

I might just unplug the 101 and blast the contacts, then hope I can get it plugged back in.

 

Seriously? Tip 2 at www.cruiser54.com!!

 

CRUISER'S MOSTLY RENIX TIPS

RENIX C101 CONNECTOR REFRESHING

OCTOBER 30, 2015 SALAD 39 COMMENTS EDIT

 

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 more than 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.

That said, the cleaning described below is a real MUST DO right off the bat for any new-to-you Jeep. But, I strongly advocate eliminating the C101 at some point by following the procedure with photos and video in Tip 27. Soldering skills are required and it takes about an hour and a half.

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 ¼” 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.

If you wish to eliminate this connector entirely (highly recommended), see Tip #27 – C101 Elimination

[cruiser54]

well, have you done it yet? Nothing to fear. I've done dozens of them without an issue. 

[brucecooner]

19 hours ago, cruiser54 said:

well, have you done it yet? Nothing to fear. I've done dozens of them without an issue. 

I think I had only ever considered C101 removal as the only option, and forgot about the cleaning tip. 

 

But it's been a busy week at work, trying to get a project sorted before a deadline, and then more plans this weekend. 

I've been bummed that I haven't had more time to fiddle with the Jeep.

 

 

[cruiser54]

Well, the c101 cleaning is very important to do. 

[brucecooner]

I had a few minutes of daylight and no other obligations today, and I couldn't leave cruiser in suspense, so I tackled cleaning the C101 today.

 

The connector isn't as delicate as I had imagined it to be based on looking at it from the outside.

But once I opened it up, ick-o-rama.

 

The pins are pretty well gummed up with what looks like corrosion, but I didn't see any signs of the tar-crap, leading me to

think this thing has been cleaned out before.

 

Regardless, it needed cleaning so I went in with brake cleaner for a while, then switched to the electrical cleaner, going at it with a metal brush and an old toothbrush too.

When I'd spray the cleaners down into the connector, some brown fluid would flow back out.

It might have been rust or the old tar stuff's remains. 

I got as much brown fluid as I could out, but I feel like there's more left in there.

 

I took q-tips moistened with electronics cleaner to everything metal I could reach until the q-tips quit coming back brown.

I tried to tighten the female pins with a small hook, it looks like there's only one side, that mates to the bottoms of the male pins, but I could barely budge them.

As a final step, I coated a q-tip with oxgard and hit all the male pins, not sure if it will help much but it might.

 

It was a bit after dark when I got done, and it was still not what I'd call clean looking on the inside, but at least the metal parts looked sort of metallic again.

 

 

There was a slick looking, greasy sort of resin coating on the inner plastic surfaces that I never got rid of.  Again, maybe the remains of the original tar crap.

I had been afraid this would be a bear to reconnect, but the bolt did the work of seating and firming up the connector.

 

Once I bolted had it back together she started right up, so at least I didn't bungle the job.

 

I was wondering if this would fix the wandering idle, but it was still there.  

No matter, it definitely needed doing.

 

Big thanks to cruiser and the others for nudging me forward on this.

 

But this leads me to my next concern.  I park it in a driveway, and I'm pretty sure some of this corrosion is due to water making its way under the hood.

 

I can see some water drop witness marks on dusty surfaces, and my uncoated brake master cylinder has rust spots all over it.  (disappointed about that too, it's a Napa part, I didn't try to skimp on it)

 

Also that deep well at the corner under the hood, where the firewall meets the inner fender, has a little bit of rust waaaay down there.  I keep leaves and stuff out of there as much as I can, but I want to try and get a dremel wire cone down there and then treat and seal it somehow.

 

This leads me to wonder if there's a gasket I could install around the edge of the hood or something like that to keep the wind from blowing so much water into the engine compartment.

 

At the very least, I think I need some sort cover to keep water off the C101.

 

Anyone have any experiencing keeping rainwater from gushing under the hood?

 

 

 

 

 

 

 

 

[acfortier]

Are you saying water is getting in via where the hood and cowl meet? I would get a new seal for there, if you still have the old one: https://www.summitracing.com/parts/pqp-cs-6110-84?srsltid=AfmBOoqX-FHNajIiJwIZWZ4PHSxFTHYwfaafbp_ebxmnN7gw8mrDK7djHWA

 

EDIT: I think I installed the 97+ one, but not sure if that was intentional on my part or not? Can't remember if it's an "upgrade" over the older style? https://www.prp.com/product/detail/353642?SearchType=AGR&sort=u.Name&paginationCount=24&year=1998&make=&model=&type=All

[brucecooner]

On 5/17/2024 at 5:38 AM, acfortier said:

Are you saying water is getting in via where the hood and cowl meet? I would get a new seal for there, if you still have the old one: https://www.summitracing.com/parts/pqp-cs-6110-84?srsltid=AfmBOoqX-FHNajIiJwIZWZ4PHSxFTHYwfaafbp_ebxmnN7gw8mrDK7djHWA

 

EDIT: I think I installed the 97+ one, but not sure if that was intentional on my part or not? Can't remember if it's an "upgrade" over the older style? https://www.prp.com/product/detail/353642?SearchType=AGR&sort=u.Name&paginationCount=24&year=1998&make=&model=&type=All

 

I hadn't really looked at it closely until I read your comment, but the cowl gasket is in good shape. 

 

I think the water is blowing in from the driver's side hood gap when the wind picks up out of the west. I park facing north and we get some pretty strong gusts with some of our storms.  I don't have a windshield washer reservoir at that spot anymore, which would block some from blowing on my master cylinder, but I'd rather it stay reasonably dry under there.

 

I took a picture that shows the cowl gasket in place, but a HUGE gap down the fender.

I wonder if it's possible to modify a cowl gasket, or any piece of rubber I guess, to fit under that seam.