corroded connectors, harness renix 4.0 aw4

[davehoose]

Well, everyone here has been so helpful and I appreciate it! I have another electrical problem with my laredo. I have traced the root of my problems with backfire and bucking to the crankshaft position sensor (I think). I tried the ever popular unplug, replug and this works - for awhile. I took a good look at the connector and see that it is severly corroded. Anybody have this problem before? It acts up badly when (like tonight on my way home from work) it is raining (or snowing). I was wondering if I should just replace the harness, or if this is a replaceable plug? I used to use something on my battery cables to clean them back in the day, maybe this would work?

any reply is worth a try.
thanks

p.s. it's an 89 cherokee laredo with aw4 4.0 and 96000 miles

 

[Roads]

96,000 on an 89, nice. Is that a rebuild or a lawn ornament?

 

[Matthew Currie]

I had this battle constantly with my 87. One of my favorite substances (and it's even a legal one!) is no-flash contact cleaner. You can get it from various sources, including, at least in the past, Radio Shack under the name of TV tuner cleaner. A good bath with that, then a few plug-replug cycles would help a lot. A little silicone grease can help too.

If the connector is just too corroded to stay clean, it might be worthwhile replacing just that piece. You might be able to go to a junkyard or somewhere and snip out one clean weatherpack connection from somewhere and solder it in

If the CPS still requires unplugging and replugging after the connector is known to be good, it might also be a symptom that it's about to fail, and it might be a good idea to replace it.

 

[5-90]

Weatherpack shells and terminals can be had at your local parts house, under the Motormite HELP! brand. Clip it very close to the end, reterminate, and reassemble.

A little dielectric grease (automotive) or Gardner-Bender Ox-Gard (hardware store, electrical section) goes a LONG way toward keeping it clean.

I'd also just get a new sensor while I was about it - even if you're got under 100K, it's not in the best operating enviroment (especially exhaust heat!) and probably wants replacing.

5-90

 

[davehoose]

96,000 on an 89, nice. Is that a rebuild or a lawn ornament?

Definitely a lawn ornament before I got it. The interior is super clean, the back seats look new, the fronts show little wear. The air still blows super cold and the removable extension light under the hood even works! I've been under the thing a few times (replaced the o2 sensor and the muffler) and there's virtually no rust. I don't know the history of the vehicle but I got it pretty reasonably. The former owner probably didn't want to deal with the rexix system quirks, but my multi meter has been pretty much all I needed to get it running good. Had to adjust the throttle position sensor (big difference) and replace the air charge sensor. The 4wd works great. Really a nice rig, few cosmetic issues - bumpers really and a dent in the pass side door. A wire fell off the driver door window motor and i just soldered it back on, replaced the door speakers with 2 I bought at the dollar store (really) and they sound great. It had the Jensen speaker set up with the tweaters in dash (they still work great). I'm definitely an xj fan now.
Sometimes you get lucky!

 

[davehoose]

I had this battle constantly with my 87. One of my favorite substances (and it's even a legal one!) is no-flash contact cleaner. You can get it from various sources, including, at least in the past, Radio Shack under the name of TV tuner cleaner. A good bath with that, then a few plug-replug cycles would help a lot. A little silicone grease can help too.

If the connector is just too corroded to stay clean, it might be worthwhile replacing just that piece. You might be able to go to a junkyard or somewhere and snip out one clean weatherpack connection from somewhere and solder it in

If the CPS still requires unplugging and replugging after the connector is known to be good, it might also be a symptom that it's about to fail, and it might be a good idea to replace it.

I actually have the radio shack tuner cleaner. Will this clean the corrosion? I use it on my guitar (an old fender stratocaster with a volume control that likes to get dirty after a few months).

 

[8Mud]

There is a kit to bypass most of the harness for the Crankshaft position sensor, Eagle posted about it a couple of years ago (a search may show up something, possible under connectors or CPS. It was designed for the pre 89 XJ's with the C101 connector, but probably could be adapted to the 89 without much trouble. It is supposed to strengthen the CPS signal by shortening the run to the computer from the CPS.
A corroded CPS connector sounds like a good place to start looking, but bucking can have numerous causes. O2 sensor has a tendancy cause bucking especially around 2000 RPM in high gear with moderate throttle, often while mildly accerating or under low vacuum condiditons. New doesn't necessarily mean good, I bought one 02 sensor that refused to idle. 02 connector is another possiblilty, even the contacts at the O2 heater relay can cause this. I've had bucking after the surge tank sprung a leak and drenched my relais (ASD and O2 sensor heater) in coolant. Distributor cap and coil to cap cable are also a possiblility (intermittant high voltage leak). Corroded contectors to the coil in power (large yellow wire), either at the coil or the next connector up stream, causes low coil voltage. The fuel rail front harness that goes down the front of the motor is prone to cooking on the exhaust manifold and causing O2 sensor problems. The CPS cable cooking on the exhaust manifold also causes problems, it can be rerouted and tied off to the speedo cable to keep it out of harms way. Worn distributor and timing chain can be helped by reindexing the distributor. Just a few things to look at if the CPS connector doesn't cure the problem.