cruiser54

Great idea.. http://comancheclub.com/topic/17377-cad-fix-1/

More power. If you have a 3" or more lift, you can route the pipe like it was. I don't though. Unlifted, be sure to have your exhaust guy tuck the pipe out of the way of driveshaft up-travel. I stole your photo airspeed. Thanks.

Click on the link in my signature and do the ground refreshing, C101 refreshing, Connector and relay refreshing, and sensor ground testing before proceeding down any other rabbit trails.

750 in D.

Melted no. Disconnected.......YES. But was still tucked in slightly so not easy to see in dark with flashlight last night. Nice firm push to click it closed for sure this time and Presto we have fire. THANK YOU! This forum rocks Woohoo!! I love happy endings.

Is the CPS wiring on the exhaust manifold and all melted?

CPS generates it's own signal. Should be fine. TPS won't keep it from starting. What about the coil/ICU right near the battery? Never drive with a battery not fastened down...........

The factory downpipe has a "crush" in it that appears to be for front driveshaft clearance. That's not why it's there. It was done to slow the exhaust down and heat up the catalytic converter faster. A good muffler shop can make you a custom downpipe using two 45* angles instead of the one 90* angle the stock one has. Wait til you see just how much that pipe is crushed. Probably 30%.

Get one for an auto trans. Cheaper. Get a good quality one, not the cheapie.

Downpipe mod ?? Top secret. I haven't done a write-up on it yet.

Do the downpipe mod while you're at it and pick up some ponies.

Click on the link below. And, do the tune-up stuff as recommended.

Voltmeter reads battery voltage with the key On, right? What does that voltmeter do when you turn the key to Start?

I think it might have been late 90 or 91. Pretty sure all 89s had 21 splines.

You would have oil that looks like a chocolate milkshake if the head cracked. And, a compression test will not detect the cracked head.

Ever refresh your grounds? Refresh your connectors in the engine bay? 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 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 Added an instrument panel ground? Improving the Instrument Panel Ground The ground point for the complete instrument cluster on your XJ or MJ is located up under the driver’s side dash. If you lay on your back and look up under there with a flashlight, without wearing a hat, you will see a black wire attached to a shiny piece of metal almost directly above the hood release knob. The screw will have either a ¼” or 5/16” head on it. This ground point is responsible for handling the ground circuit for the following items: Dome lamps, Seatbelt and key warning, trans comfort switch, wiper switch, headlamp switch and delay module, fog lamp switch, cargo lamp switch, all instrument panel grounds and illumination, power windows and door locks, cruise control dump valve, and a few more things. The problem is that where the ground point is located does not have a good contact with the chassis where the ground should be. The solution is simple. Make up a jumper wire with #10 gauge wire about 10” long. On one end, crimp on a ¼” round wire terminal. On the other end, crimp on a 3/8” round wire terminal. Remove the screw from the existing ground wire and attach the small terminal of your jumper so that the original wire and your new jumper share the same attaching point, one over the other. Look above the driver’s side plastic kick panel just forward of the top of the hood release knob. You will see an 8mm stud there. Attach the large terminal end there with a washer and nut over it tightened securely. **Special note for Comanche owners: Make your jumper wire 12” long and attach it on the driver’s side kick panel close to the fusebox on the 8mm stud.** Revised 11-29-2011

Ever do the ground refreshing and other stuff in my link below? C101 cleaning Connector and relay /receptacle refreshing Check sensor grounds Intake manifold bolts loosened up? Vacuum line from throttle body to MAP sensor have a small crack?

Discussing removal of federally mandated emissions equipment is not allowed on the forum.

The lead alloy answer is pure bull$#!&.

CRUISER’S VACUUM TEST FOR EXHAUST RESTRICTION Your vacuum gauge should come with an instruction booklet outlining the procedure. Hook the vacuum gauge up to a source on the intake manifold. Start the engine and note the vacuum reading. Usually 17 to 21 inches of vacuum. Throttle the engine up to 2,000 to 2,500 RPM for 20 seconds or so and the vacuum reading should stabilize to the same reading you got at idle. Let the throttle snap shut. The vacuum reading should shoot up about 5 inches of vacuum higher for a second and then come quickly down to the original reading. If the vacuum reading stays high and comes down slowly with jerky needle movements, you have an exhaust restriction.

33002970, 33002971, 33002972 o-rings. Yes, they get hard as a rock.

CRUISER’S VACUUM TEST FOR EXHAUST RESTRICTION Your vacuum gauge should come with an instruction booklet outlining the procedure. Hook the vacuum gauge up to a source on the intake manifold. Start the engine and note the vacuum reading. Usually 17 to 21 inches of vacuum. Throttle the engine up to 2,000 to 2,500 RPM for 20 seconds or so and the vacuum reading should stabilize to the same reading you got at idle. Let the throttle snap shut. The vacuum reading should shoot up about 5 inches of vacuum higher for a second and then come quickly down to the original reading. If the vacuum reading stays high and comes down slowly with jerky needle movements, you have an exhaust restriction.

Local paint store mixes it up for about $16 per aerosol can.

They have the ability to shut the fuel off on decel.

No kidding you messed it up. What was the question?