BUY JEEP PARTS: Dana 44 | Catalytic Converter | Jeep Gas Cap | Distributor | Carburetor

In all of your future Jeep Creep questions, please list your first and last names, your hometown, and your state/province/country, so that we can publish that information here. If you don’t provide this information, we may not be able to publish your question and answer. Don’t forget to be as complete as possible with the description of your Jeep and its problems, too. In addition, if there is a recall issued on a Jeep model by the National Highway Traffic and Safety Administration (NHTSA), I will publish it here for your information and education. See all of the posted recalls at www.odi.nhtsa.dot.gov/cars/problems/recalls/recallsearch.cfm.
—Jim Brightly

No Cat

I recently had my catalytic converter taken off my ‘98 Jeep Wrangler 4.0L with auto trans. My buddies were telling me that I would increase fuel mileage. Best I can tell it bypasses the back O2 sensor. I have less power and worse fuel mileage than before. What’s up with that? It runs fine; no skipping or noises, just less power and less mileage. What to do? Should I replace the cat?
Melvin Bass

The lack of a catalytic converter is your problem. The O2 sensor is sending what is now mistaken data to your engine’s computer, causing the computer to flow more fuel to the engine. This causes an over-rich mixture, causing the reduced power and increased fuel usage. Replace the OEM cat with a high-flow, low-restriction aftermarket unit and you’ll get your power back plus a slight increase, and better mileage.

Supercharged Cherokee

I have a 1998 Grand Cherokee with the 4.0-liter. I want to supercharge it but have no clue about the specifics. Help me?
Motta4.0
Milwaukee, WI

First of all, do you mean supercharge or turbo charge? There is a difference. Also, are you sure you want to do this? If you live at high altitude, I can understand it. However, living in Milwaukee as you do, I can’t think of another reason unless you plan on drag racing. In addition, are you aware that you’ll have to run the highest test gasoline from now on regardless of what type of air-charging system you use?

Bad Brake Lights

My ‘93 Wrangler Sahara has a brake light problem. Sometimes when I push on the brake pedal the driver’s side brake light doesn’t go on until I turn my blinker on. I have a new brake light switch in it.
Brian
Lodi, CA

Your turn signal switch could be bad. Cycle the hazard switch about a dozen times and see if there’s any change. If no change, replace the turn signal switch.

Vacuum Lines

I’m looking for a diagram of the ‘96 Jeep Cherokee vacuum hoses. My jeep has been stalling out when stopping. This only happens in cold weather. It starts right back up, but stalls when stopping. Help!
Cathy Wojcik

OD or Not

Would it improve my ‘04 Rubicon’s engine life to switch off the overdrive while driving in the city? I have already switched to Mobile One. This is my first TJ and I want to keep it in good health for a long time. Thanks.
Rick
Hallsville, MO

The only time the OD could cause you some trouble—and it won’t be with the engine but with the transmission—is if you’re towing and it keeps shifting back and forth between 3rd and 4th. This “hunting” will cause overheating in the transmission and shorten its life. Actually, shutting off the OD without the hunting could shorten the life of the engine by causing it to rev higher needlessly. If you’re worried about lugging the engine (I’m assuming that’s what you meant by hurting the engine), an automatic won’t allow that to happen.

Bigger Rims

I have a 1999 Wrangler Sport with stock rims and tires (15-inch rims and 235/75-R15 tires). I am looking into getting new rims and tires but would like to know if I can put on 31x10.5-inch tires without any modifications? Also what kind of backspacing will I need and width of rim for this size tire? If this size tire does not work then what would you recommend?
Scott
Lancaster, PA

Thirty-ones will fit. They may contact metal during extreme turns over extreme terrain, but other than that they’ll fit. You could also use the original rims if you want to save some money. Unless you need a tire with wide-open treads for the mud in Pennsylvania, which would wear rapidly, I’d highly recommend Goodyear MT/R tires (see www.goodyeartires.com, Goodyear provides a tire chart with recommended rim widths). They’re tougher than hell, fairly quiet, excellent traction, and long lasting. If you still want new wheels, check out 4-Wheel Parts and/or 4-Wheel Hardware Web sites for their sales deals.

Dodge Swap

I have a 1989 Jeep Cherokee Pioneer with the six-cylinder 4.0L, and I was wondering if I could put a 318 Dodge V8 in there? I can’t find anything on that swap.
Logan

Shore can. You can install almost any engine in almost any Jeep, providing you have the patience, ability, money and equipment. However, there are several engines—mainly Chevy or Jeep—that would be much easier to install. Contact Advance Adapters to ascertain if AA makes the adapter, motor mounts, etc., that you’ll need. I’m also sure you can get a wiring loom from Painless Wiring.

Mad Module

I have a 1989 Jeep Wrangler Laredo 4.2L. I lost power going to the distributor, so I replaced the ignition module. It cranked fine for a couple days. Now I have no fire at the distributor again.
Steve
Youngsville, NC

MSD Ignition

I have a 1988 YJ 4.2L bored 60 over, ported/polished head, cam upgrade, 4 barrel, headers; all for off-road use. I want to upgrade the ignition system. I was thinking about MSD. What would you suggest?
Bill Bittle

That sounds like an excellent idea to me, and the Jeep doesn’t sound too bad either. Depending on what MSD model and kit you purchase, you may need a module to drive the tach, if you have one.

Ill Instruments

My daughter’s 1998 Grand Cherokee’s (bought used) instrumentation fades in and out, will go out for a while then comes back on. Also there are a couple of black areas in the cluster. Any suggestions to fix this economically? Thanks for the help!
Bill Bronander in NJ

The instrument cluster needs to be repaired , rebuilt or replaced with a known-good unit from a junkyard.

No Heat Heater

I have a 1995 Wrangler YJ. My heater quit working. I checked the fuses and that didn’t do it. I was wondering if you could help me.
Moises Garcia
Marshalltown, IA

Moises, if you checked on both sides of the fuse for juice, what you need to do now is trace the wiring. I know it’s going to be difficult, but it could save you some money. Check for juice on both sides of the switches, then at the motor itself (make sure the switch is on when you check at the motor). If juice is present at all these locations, you’ll probably need to replace the fan motor. By the way, I forgot to ask if it’s just the fan motor—which I assumed from you checking the fuses—or is there no heat coming from the registers at all? If it’s no heat at all, it could be the vacuum duct switching controls.

Wrangler S/SE?

I just purchased a ‘94 Jeep Wrangler. When I took it to get insurance on it I was told that it’s an SE. But when I look it up on NADA, there is no ‘94 Jeep Wrangler SE. Can you help me figure this out? I’m really just trying to see if I overpaid for the vehicle.
Vincent Orta
Commerce, GA

I’m not sure whether you paid too much or not, but according to my library, the “S” and “SE” model names were interchangeable at different points in the model run and were the base models. During the first few years the backseat and rear bumperettes were optional, some years the 6-cyl. engine was an option, other years only the 4-cyl. was available in the “base” model.

Brake Warning Light

I have an ‘86 CJ7. I had a front brake line rub out. After replacing the line and bleeding the brakes I still have a brake warning light on. How do I remedy this?
Bill Grinder
Santa Maria, CA

Your proportioning valve needs to be re-centered. All the info should be found in the proper repair book. I hope you enjoy the ribs and tri-tip at the Santa Maria Elks. We really miss the ribs and the dunes living in Arizona. Too bad they closed down Devil’s Slide years ago.

As usual each month, I’m shouting out a big THANK YOU to Paul Schupp at Rock Lizard 4x4 in Kingman, Arizona, for his invaluable assistance in answering many of the Jeep Creep questions.