87 XJ no spark

cleaned throttle body when I adjusted the TPS. How clean should it be? I didn't pull it off and soak it in cleaner, or anything like that. Sprayed it with some carb cleaner and wiped off the inside with the rag. Wasn't that dirty. Not much carbon buildup that I saw.

Wires, cap, and rotor were forgotten on the last shopping trip. But I'll be doing them this weekend.

Thanks. I really appreciate the help. If it's carb'd I can get it running, but never woulda gotten this one without ya'll's help. And i'm learning, which always makes me happy. Only problem is that now my girl wants me to keep this one and sell my 77 cherokee.
 
Did the rest of the tune-up. She runs better now. She's not legel yet, and has those darn 20s on her, so I haven't gotten to drive her very far (the 20s suck on the dirt roads, which is where we get to drive with no insurance and stuff).

My j10 lost a ujoint, so the xj is gonna be getting all legal'd up this week. Will let ya know how she goes.
 
Got it all legal. Runs good. Still slow to start (will try another battery). She runs super well off idle, but still doesn't have a steady idle.
 
pleontks said:
Changed spark plugs. Old ones were autolites, black, and gapped around .80

Tightened remainder of intake bolts. Some were loose, some were not.

Moved vacuum ball to underneath coolant reservoir, and ran those vacuum lines.

Still takes a while to start, but my 'home-fixed' battery still needs some breaking in.

Still idles rough. Off-idle sounds great.

So, summary so far:
New CPS made it run
Oil change
spark plugs
New vacuum lines (soft)
tightened intake bolts
adjusted TPS
installed 20" rims (most likely cause of all problems, an embarassed jeep isn't gonna run well)
Filled coolant
Moved vacuum ball to under coolant reservoir
cleaned air filter (it still smells like rat pee, but I can see through most of it)


I'm now at a loss, other than testing more sensors, but I don't even know what most of them are called. I can find no vacuum leaks. Maybe o2?
Click to expand...


Don't see these three things on the list.

Renix Ground Refreshing
The Renix era XJs and MJs were built with an under-engineered grounding system for the engine/transmission electronics. One problem in particular involves the multiple ground connection at the engine dipstick tube stud. A poor ground here can cause a multitude of driveabililty issues, wasted time, failed emission tests, and wasted money replacing components unnecessarily.
The components grounding at the dipstick tube stud are:
Distributor Sync Sensor, TCU main ground, TCU "Shift Point Logic", Ignition control Module, Injectors, ECU main ground which other engine sensors ground through, Oxygen sensor, Knock Sensor, Cruise Control, and Transmission Sync signal. All extremely important stuff.
The factory was aware of the issues with this ground point and addressed it by suggesting the following:
Remove the nut holding the wire terminals to the stud. Verify that the stud is indeed tightened securely into the block. Scrape any and all paint from the stud’s mounting surface where the wires will attach. Must be clean, shiny and free of any oil, grease, or paint.
Inspect the wire terminals. Check to see that none of the terminals are crimped over wire insulation instead of bare wire. Be sure the crimps are tight. It wouldn’t hurt to re-crimp them just as a matter of course. Sand and polish the wire terminals until clean and shiny on both sides. Reinstall all the wires to the stud and tighten the nut down securely.
While you’re in that general area, locate the battery negative cable which is fastened to the engine block just forward of the dipstick stud. Remove the bolt, scrape the block to bare metal, clean and polish the cable terminal, and reattach securely.
Another area where the grounding system on Renix era Jeeps was lacking is the engine to chassis ground. There is a braided cable from the back of the cylinder head that also attaches to the driver’s side of the firewall. This cable is undersized for it’s intended use and subject to corrosion and poor connections at each end.
First off, remove the cable end from the firewall using a 15mm wrench or socket. Scrape the paint off down to bare metal and clean the wire terminal. Reattach securely.
Remove the other end of the cable from the rear of the head using a 3’4" socket. Clean all the oil, paint and crud from the stud. Clean the wire terminal of the cable and reattach securely.
A suggestion regarding the braided cable:
I prefer to add a #4 Gauge cable from the firewall to a bolt on the rear of the intake manifold, either to a heat shield bolt or fuel rail bolt. A cable about 18" long with a 3/8" lug on each end works great and you can get one at any parts store already made up. Napa has them as part number 781116.
A further improvement to the grounding system can be made using a #4 cable, about 10" long with 3/8" terminals at each end. Attach one end of this cable to the negative battery bolt and the other end under the closest 10mm headed bolt on the radiator support just forward of the battery. Napa part number 781115.
For those of us with Comanches, it’s very important to remove the driver’s side taillamp assembly to access the ground for the fuel pump. Remove the screw holding the black ground wire. Scrape the paint from the body and corrosion from the wire terminal. Reattach securely.
If you want to upgrade your grounds and battery cables in general, contact Jon at www.kelleyswip.com. He makes an incredible cable upgrade for a very reasonable price.
　
Revised 03-04-2013

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 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.
　
Revised 03-02-2013

I suggest unplugging EVERY electrical connection in the engine bay you can find, whether engine related or not, and spraying it out with a good electronics cleaner, visually inspecting the terminals making sure they haven’t retracted into the plastic holder, and then plugging it back together. There’s a critical 10-pin connector for the front lighting system located in front of the air cleaner and behind the left headlight assembly. Don’t miss that one. Also be sure that the connectors to the ballast resistor mounted near the air cleaner housing are clean and tight.
ALL of the relays should be removed, the terminals wire-brushed until shiny, and the receptacles sprayed out with contact cleaner. Then plug them back in. I do this on every Renix Jeep I purchase or work on for someone else.
Revised 07/23/2012
 
Did the ground refreshing. They didn't look too bad, and no noticeable improvement.

Cleaned connectors on driver's side of engine. Very slight improvement.

Eliminated c101 connector. Noticeable improvement.

Cleaned connectors on pass side of ingine. Noticeable improvement.

Installed new(different) relays from my bucket o' relays. Slight improvement.

Still seems like a vauum leak, albeit a small one. I'm thinking it could be the one that goes inside the cab for the heater controls. But I can't get to it.

I finally got the coolant reservoir sealed, and the system purged. So no more bucking randomly while driving.

While in the dash to do the radio, I fixed all the rat-eaten wire I could find. Evidently the stereo wires tasted better than the jeep wires. Only found one stock wire that was chewed, but they ate the crap out of the wires from the stereo.

Speedo cable is broken off inside speedo. Was advised to switch entire inst cluster, so I could also have gauges.

Fan blower quit working. Fuse? Relay? I've got the haynes for it, but there's no good wiring diagrams that I've found yet.

I think that's it. Sorry so long for the update, but there are many jeeps in my yard, and they all need love :)
 
Took jeep on 500 mile trip. Ran pretty good. But now she's developing an off-idle stumble. 19+ mpg on the way there, little less on the way back, but it was tending uphill and into the wind. 4hrs nonstop both ways. I was very surprised how well the free jeep did. :)
 
X2 i cleaned mine and my intermittent no start issues went away,and yes follow all teh ground refresh instruction to a T. brought my MJ back to full function and reliability. get some dielectric grease and get to those grounds !

cruiser54 said:
Renix Jeep ICU/Coil contact refreshing
　
　
The contacts between the coil and the ICU on your Renix Jeep can become corroded and loose causing a complete or intermittent no-start condition. I recommend the following procedure as a maintenance precaution to insure this is eliminated as a possible cause now and in the future.
The coil is attached to the ICU by two T20 Torx bolts. Remove these two bolts and lift the coil up off the ICU. You will see 2 pins and 2 sets of contacts. Clean both the pins and springy contact pieces with a good electronics cleaner.
Squeeze the springy contacts closer together with some needlenose pliers. Apply some dielectric grease to the contacts and bolt the coil back on to the ICU.
While you’re right there unplug the connectors from the ICU and inspect the pins in the harness connector. Make sure the pins are not retracted into the connector. Spray out the connector and the receptacle of the ICU with the same good electronics cleaner you used earlier. Apply dielectric grease to the connectors and plug them back in.
I feel this procedure should be performed at least once in the lifetime of a Renix Jeep.
　
Revised 11-29-2011
Click to expand...
 
cruiser54 said:
Nevermind the coils for now except to do the ICM/coil refreshing in the link in my signature. Get a ground from the head to firewall!! Read about the ground refreshing in the same link.
Click to expand...
your writeups all over the web have helped me a LOT and i wanted to toss out a big thank you for the help!:farmer:
 
Gunter said:
your writeups all over the web have helped me a LOT and i wanted to toss out a big thank you for the help!:farmer:
Click to expand...

Yes, cruiser54 definetly seems to know his stuff. And seems to help EVERYONE out. Even the noobs like me who can't get the search to work right.

Thanks again cruiser54!:party:
 
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