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ok so I just got sick of all that damn heat in the cab from the exhaust. So I want to eliminate some heat and aide in helping the new cooling system. So order 100ft of black exhaust wrap and i be fixin to wrap the jeep headers. But want to know if anyone 😕 done this with good results? And shall I also wrap the down pipe as well as it runs under the cab?

Hi all, I just got my Rockauto order in with a new vacuum harness, and I got it all replaced. Now my low idle issue is fixed-ish. It’ll still idle low, but it won’t stumble and die. I noticed that my EGR solenoid was disconnected at the bottom, And when I plugged it in it ran like a top, only problem is it backfires, but only when warm, it doesn’t when cold. The EGR also makes a quack noise as well. I’m glad it’s running better now, but I don’t want to blow a huge hole in my muffler/cat, and also it’s a bit annoying. thanks in advance.

I’ve got a Canadian version 87 2.5 Comanche and was wondering if it came with a catalytic converter?

Hey all, This is my first post here, so I figured I'd do a bit of an introduction as well. I'm located in western BC and I've got myself a '90 base Comanche 4.0, 5-speed, rwd for $800CAD, looking to do a lot of cool stuff with it, but need to get the main issues sorted first. I've fixed my tail light wiring, and done the headlight relay mod, which fixed my flickering headlights. I've noticed in the right lighting I can see smoke/fumes entering the cab from what seems to be low on the passenger side (below the dash) and possibly the ripped shift boot. After a bit of reading I went ahead and replaced the exhaust manifold, and added a flex joint in a new downpipe, with new gaskets all around. I noticed a stud had been snapped in the head, so I went ahead and drilled and tapped the hole larger. Also, the cat has been removed at some point. After this, nothing has changed. I'm still seeing and smelling fumes leaking into the cab. I noticed that I have a filter on top of the valve cover that leaks oil out onto the cover. Could this possibly be a source of the smoke? Everyone I've taken along to check it out has said the smoke smells more like oil than exhaust. The weird thing is, it only smokes under load. If I'm sitting in neutral at a light, I can rev it all day and not have any fumes come in, same with going downhill in gear. Going up hill is another story, it's at it's worst when on the gas in 3rd - 5th gears, especially going up hill. I'm at a loss here, as I've checked the whole exhaust system and can't find any leaks. The underside is a bit oily, but its nothing crazy, could I have possibly blown a seal that shoots oil onto the exhaust under load? Downpipe still looks clean too. Another thing I should note, I have almost no floor on the passenger side, which is on the list of things to fix. I've thought about repairing the floor and hoping for the best, but would rather fix the source of the problem instead of putting a band aid on it. Any input you might have would be GREATLY appreciated, as I love this lil truck and want to fix it up the way it deserves. Also, it makes first dates a bit embarrassing when the smoke starts rolling in lol Thanks!

For those of us that still love our 4 screaming squirrels, here is a little necessary upgrade/Egr Delete The manifold I used was from a 2.5l yj ( a knock off pacesetter header from ebay) Header Link and EGR Block off plate There are going to have to be some modifications, the new mid pipe is shorter than the original, so you can either lengthen your new mid pipe or lengthen youe existing exhaust set up if you are going to reuse it It is short about 1-1.5 ft, so it gives you the opportunity to run a new exhaust if you want

So as stated in my previous post, I'm about to replace my down pipe, muffler, cat, and tail pipe due to rust and holes etc. 1989 Pioneer 4.0 5 speed manual. Thinking now that I'm replacing everything else, I should replace my manifold while i'm at it. Looking online for pricing and it's a bit expensive compared to everything else. I found stainless steel headers for way cheaper but they say they are for a 91-95 (or something) Wrangler and Cherokee. Cheaper and better looking. Will other 4.0L exhaust manifolds fit on our MJs 4.0, without heavy modifications?

I'm sure there are probably several other threads about this already. I did searches but didn't find quite what I was looking for. I have holes in the down pipe, I don't have a cat but don't see any evidence that I ever did. All the pipe and hangers and everything seem to be where they should be. So I'm looking at replacing everything from the exhaust header down. I have never done this and have questions. Everything appears to be bolted on, is this correct? I would like to add the cat back on. I assume I had one from the factory, but it sure doesn't look like it. Then my other question is, what mufflers will give me the best sound? I don't want something annoying, but I'd like a good growl if it's possible from a 4.0L. I've found the pipe online for like 30 bucks each. So what else do I need? Gaskets? Hangers? Clamps? Any input would be great. Thanks all. 1989 Pioneer. 4.0L Long Bed.

I'm sure there are probably several other threads about this already. I did searches but didn't find quite what I was looking for. I have holes in the down pipe, I don't have a cat but don't see any evidence that I ever did. All the pipe and hangers and everything seem to be where they should be. So I'm looking at replacing everything from the exhaust header down. I have never done this and have questions. Everything appears to be bolted on, is this correct? I would like to add the cat back on. I assume I had one from the factory, but it sure doesn't look like it. Then my other question is, what mufflers will give me the best sound? I don't want something annoying, but I'd like a good growl if it's possible from a 4.0L. I've found the pipe online for like 30 bucks each. So what else do I need? Gaskets? Hangers? Clamps? Any input would be great. Thanks all.

Actually an XJ thing, but it's the same for what matters in this case. 89, Renix, 4.0L Factory exhaust is scabbed, broken, doesn't fit right, has a 'newer' catback on it that's totally rotten because it was bare steel. Anyways, Renix parts are always harder to come by, and seem to be a premium. So I was thinking I'd massage the intake and install this header: http://www.amazon.com/Wrangler-Cherokee-Performance-Stainless-Polished/dp/B00JA1BGYY?ie=UTF8&psc=1&redirect=true&ref_=ox_sc_act_title_1&smid=A1F86TF7G43XA2 Any experience with it? Reading the reviews on Amazon is mixed. The flange thickness issue is well, an issue, but it can be dealt with by making some custom washers. Obviously there also isn't a bung for my O2 sensor, but on to that... Who makes a stainless downpipe, or 'front pipe' as it seems to be called by exhaust manufacturers, that will fit an HO and have the bung in it? Failing that, does anyone know what flange style can be bolted to an HO header? These maybe? http://www.summitracing.com/int/parts/vpe-1471/overview/(they sell individually also) Is there a flare piece on Summit that will fit the needed donut gasket? Closest I think I can find is for 2.5" pipe: http://www.summitracing.com/int/parts/vpe-2599/overview/ If I have to use that (if it would fit on the header and seal) I would neck it down to 2.25" right away. I do not have any issues with front driveshaft clearance but will have trouble fitting larger pipe from there back. Unfortunately 2.25" parts seem to be much rarer than 2.5". I can buy some U-bends and make the exhaust from the header back if I know what flange and flare will bolt up. Otherwise I'm at a bit of a loss. Buying a weld in bung for the O2 isn't a big deal. I can get everything from there back easily enough if I just buy normal universal parts. Yes, I can weld stainless well enough.

Hello! I searched high and low over this great site and have yet to find a good source for a DOWNPIPE (s-pipe...?) replacement for my 1992 MJ I6. I'm looking to replace the header with a BANKS unit and at the same time throw in a mandrel bent 2.5" downpipe (I think this is the correct nomenclature...it's the exhaust pipe connected dorectly downstream of the header.. Any suggestions? I keep finding the crushed stock unit (pinched to less than 2.25" right near the header...)....but that's not what I want. Do I need to have a shop fab up a custom one? I'd like not to have to think about for a while, so maybe a stainless unit? Definitely would like it to be smooth mandrel bent and 2.5" diameter to match my Magnaflow exhaust that's turned down before the rear axle. Any help will be appreciated! :thumbsup: :bowdown:

Building my exhaust. I decided I wanted to run the pipes and muffler high in the frame, and have nothing exit under. So I cut a hole in the side of the bed, and ran exhaust there. The muffler will mount high under the bed, just in front of axle. Its a same side IN / OUT. Its a larger muffler, for a deeper sound. I'll be putting an 8" flex pipe near header to prevent header cracks. I'll be wrapping the headers (already done). And wrapping most of the exhaust piping. For a few reasons, one the pipe runs near the transmission and I want to keep heat down. And the hotter the exhaust gasses the better the flow. An Exhaust that runs too large of a pipe, or too long of a pipe will have issues, as the gasses cool. (Its dry where I live, so I'm not worried about rust due to moisture in the wrap) I'm going extreme on the mounting too, to insure proper weight, and strength. multi rubber isolators. (Exhaust is not not done, that tip is just hanging in these pictures) Image Not Found Image Not Found

I have a 1991 MJ 4.0L, 5 sp standard which I plan on installing duel exhaust from the new duel exhausr header I installed. I want to run the duel exhaust all the way from the header duel outlets, thru glasspacks, all the way out the rear of the truck. Does anyone have any good or bad info on such a project?

In this topic you will read about what I have done so far with my 1989 Jeep Comanche Eliminator Edition. I am simply making this topic because I like to read what other people have done and what their experiences are so I can learn from them. So if you have any questions or comments about what I have done let me know! I HAVE PICTURES!! :rotfl2: I bought it with 32,000 original miles. Exhaust----------------------------------------------------------------------------------------------------------------------------------------------------------------- Flowmaster Delta Series Exhaust High flow cat . :MJ 1: . I had the cat and muffler welded together as well as a down pipe tip welded at the end of the exhaust The cat was then welded onto the flange by the bottom scrap bar that supports the transmission I had my exhaust/intake manifold gasket go bad on me so I replaced that and if anyone has questions on how to get to it just let me know. You do have to take the injectors off which I didnt know. I would also recommend a high quality gasket so you don't have to go through that long process again. Intake------------------------------------------------------------------------------------------------------------------------------------------------------------- I bought a high performance oiled cotton air filter that you can clean with a solution. It has a warranty replacement. Good results and I like it. Here is the website: http://www.greenfilterusa.com/ :driving: Regularly clean the throttle plate. Tried the seafoam procedure to clean out the intake manifold to get the carbon out once. Id say its a good thing but do not do that often. Maybe every 50,000 miles Electrical---------------------------------------------------------------------------------------------------------------------------------------------------------- Upgraded the grounds on the engine, firewall, and inside one of the main wiring harnesses. Refer to Cruiser54's instructions! Added LED lights in my dash. Pretty cool I think. 8) I spliced the brake lights to wire in a four wire trailer plug. I did not cut the original truck brake wire though. I actually carefully just cut the insulation off and then soldered the plug wires on. This way I will always have a complete wire section for my truck brakes just in case the soldering becomes bad. No headache! :group beer: I recently added a supplemental wiring harness for the headlights to get the full voltage from the battery. I bought this: http://www.amazon.com/dp/B001P29X4G/ref=pe_385040_30332200_pe_309540_26725410_item This was definitely a good upgrade! 25% brighter lights for cheap. You could go one step further and buy new e-code bulbs and housings. I chose not too...yet. Old Lighting system with stock lights and wiring harness getting ~10 V: New wiring harness with stock bulbs: :rock on: LOTS of ground checking and such because of a low idle issue. You can find my experience in my signature........ Exterior--------------------------------------------------------------------------------------------------------------------------------------- Undercoating! As you can see I undercoated the bottom of the side panels just low enough where you cannot see if you were standing. I also coated part of my door jam so when I kick my feet off so no dirt gets inside my truck it won't scratch that surface. But where that wider coating is on top i guess you can say, is a black plastic cover that screws into those holes. So it covers the coating but I did it anyways. Painted my bumpers a nice black finish. I have a fiberglass cap on the bed. Wax and keep clean! :clapping: NEW TIRES and 2" Lift. BFG 31's with a 2" coil spacer and rear shackles. Interior------------------------------------------------------------------------------------------------------------------------------------------------ I made my own cupholder! :yes: It is an interesting concept but it works AWESOME. I used foam from a couch cushion and cut it into the shape of the console. Then dug out the holes for the cups. I made the holes a little smaller because this puts side pressure on the cups when you put them in. Results? Drinks do not move at all Insulates the drinks and the cupholder itself is easily removable if not in use New poineer speakers in the door and side panels as well as a new pioneer radio which was a needed upgrade from my 25 year old speakers. Happy with the results. I can supply the model numbers if requested. 20% tinted windows Brakes------------------------------------------------------------------------------------------------------------------------------------------------------------------- THE BEST UPGRADE :thumbsup: :wrench: Dual Diaphram Brake Booster from a 96 Cheerokee and new matching master cylinder. I actually wrote a DIY on this and just take a look. Twice the braking power of the stock system. I highly recommend this and this is a really clear writeup with a lot of views. http://comancheclub.com/topic/39437-1996-xj-dual-diaphragm-brake-booster-conversion/ Cooling/Heating---------------------------------------------------------------------------------------------------------------------------------------------------- Flushed the coolent system a few times to keep it clean. A problem a came into is that I cannot get the drain plug in the side of the block out. A 3/8 extension does not fit and that is what it looks like should be the right tool. I havent figured that out yet so I just use the petcock in the radiator. During this cold winter :fs2: ... My heat was not normal. Jeeps should be shootin out heat that will burn your skin (not really). But I was getting like 70 deg air or less. Not right. And my temp gauge was showing fine and everything was running normal. Both heater hoses were warm... Now both were warm so you wouldnt think the heater core was plugged but it was.. I reverse flushed the heater core a few times both ways and now I'm getting amazing heat. I still have that vacuum valve so I had to clamp an extra hose in order to reverse flush. That valve also stuck during the -30 deg weather and did not let coolant flow through the heater core. Any questions please ask. Update: My heat works great now. I replaced the heater control valve because it was leaking and I also back flushed my heater core which it what really made the difference. Misc.---------------------------------------------------------------------------------------------------------------------------------------------------------------------- I did have issues with my Jeep not starting due to my bad CPS Did all of Crusier54's renix tips and tricks. He did a good job with those writeups and helped a bunch. :bowdown: I have been having idling issues with a low idle. Here is the link to the thread: http://comancheclub.com/topic/42581-renix-dead-spot-and-idiling-low/ Added a Permanent Fuel Pressure Gauge on the Fuel Rail. http://comancheclub.com/topic/12565-permanent-fuel-rail-pressure-gauge/ Upcoming projects (topic will be updating)------------------------------------------------------------------------------------------------------------- Buying a high quality gasket for that damn valve cover. It is always slowly leaking oil :fs1: COMPLETED Taking the clear coat off my rims and polishing and re-clear coating 4x4 conversion Again feel free to ask questions :waving:

Okay, my question will take some background first. My MJ just got back on the road after a year restoration. The engine was completely rebuilt. Ever since, the engine has felt like it did not have the power it once did. (I know the 4.0 is not a racer.) It just felt like it was not firing correctly. I took it to my mechanic. He checked the distributor position and timing. Everything was correct. When I excellerate in 1st, 2nd and 3rd gear, the engine hesitates and chugs as the RPM get above 2000. I don't experience it in 4th and 5th, but I don't take it up that high, either. On Tuesday this week (high of 10*), I took it in for the emissions testing. The first attempted errored out. The tech cleaned his equipment and tried again. Same result on the test: "Error Low Flow". That meant the computer was not registering enough gases to calculate a test result. They had me pull up to the next testing station. Different machine; same results. (See definition of Insanity.) I did not pass the emissions test, but I did not fail, either. I got a 5 month extension to fix the problem. However, they could not tell what the problem was?!?!? :huh???: A tech asked me if the exhaust may be clogged. That's when a light went off in my head. Several years ago, I had a clogged cat. The truck felt like I was pulling a battleship behind me. I could not get up to even 25 mph with the engine chugging. Are my symtoms from a partially clogged exhaust system? How can I test for clogs?

I'm installing a new exhaust system on my MJ including a new exhaust manifold, pipes, cat and muffler, all stock. Can this be done without disconnecting fuel line to the intake, the vacuum hoses and the throttle linkage? I'm thinking I may be able to slide the intake back a little, support it from above (couple of 2x4s across the fenders and some straps or rope) while removing/replacing the exhaust, and then slide it back in place and bolt on the manifolds with a new gasket. What's the best way to do this?