Radi

It sounds like you have a healthy miss in the video. Reminiscent of plug wires arcing to ground instead of firing the plug. Have you checked over the plugs, wires, cap, rotor? What do the plug tips look like? Sooty? Worn? Soaked in oil or gas? Is the firing order from cap to plugs correct?

cruiser54

So it runs the same whether the vacuum hose to the MAP is connected or not?

xj34

Yes it runs the same either way and no I haven't checked timing order or plugs going to do that today but I did check cap and rotor and wires all those look good

cruiser54

Do that first. Distributor rotates clockwise and the order is 1,5,3,6,4,2,.

Number is notated in the photo by the yellow wire terminal.

xj34

Ok checked firing order its good and plugs are black and smell like gas and some of the wires look a little cracked and one is slightly melted

cruiser54

Replace plugs and wires for sure. I'm wondering if your MaP is bad.

xj34

Yea I'm replacing them forsure and gonna check fuel pressure and it could be the map is going out cause it still works but doesn't mean it fully working is there a way to test the map

cruiser54

There's a test somewhere bu I don't have it at my fingertips. Check to see if the actual fitting on the MAP isn't clogged or something. They're cheap BTW.

xj34

Ok I will check tonight or I will just get a new one and try it

xj34

Ok so I changed spark plugs and wires and now it runs a little better I started it and it idled funny for a min then revs to about 1200 rpm and stays for a few secs and idles all the way back down to crap and goes right back up and if I hold the throttle a little open it will run fine and it will Rev all the way up

xj34

VID_20120801_201425.mp4

VID_20120801_201204.mp4


VID_20120801_200837.mp4

cruiser54

Okay, we're going back to basics here.

THIS needs to be done. Read it and you will see why.

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, and wasted money replacing unnecessary components.
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.
　
　
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 11-28-2011

cruiser54

THIS also needs to be done. easy to do as is the ground refreshing:
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

xj34

So do you think if I clean all the connections it will fix the problem it has now and or could it still need the tps adjusted

cruiser54

There is no doubt the connections need attention. Just do it. Both write-ups. Then, we'll dig further if that doesn't make an improvement.