Gawynz Manche Thread

[Gawynz]

Trying to get this thing on the road, failed the emissions test today. The cat and muffler and tube of the exhaust are all brand new (several idling hours or trips around the block). The guy that did the test said to go to the DMV and get a temp permit and drive it a bunch before I bring it back in, that usually does the trick with new cats. Any advice is welcome.

 

[Corban_White]

I had a 91 GMC that I didn't drive much. Every year I would have to drive it enough to drain the tank, put fresh fuel in and drive it a bit more before it would pass emissions. I would get the temp and do what the guy says, drive it. Then make sure you put a full tank of fresh fuel in it before you try again.

 

[Gawynz]

I prioritized the MJ to do list on my white board and checked enough off the list to take it out for the first time this past weekend and for the most part the MJ did great! A couple small projects before the trip...

• The battery's just been flopping around in this thing, I replaced the battery tray and got to use my new TMR Machete to make a simple hold down strap.

• Relocated the vacuum reservoir under the hood, from the factory it mounts behind the bumper.

• Pulled all the stock CAD D30 vacuum lines and plugged the t-case inputs.
• Replaced the O2 sensor and reset the ECU after failing emissions.
• Cleaned up and rerouted the wiring harness to the front clip lights, installed all the front clip pieces.
• Tacked in a couple tubes for the bumper, I'll finish weld them later, neither bumper is painted.
• Routed wires and connected the winch.

Drove to San Rafael Swell early Friday morning where I met some family, my dad brought his new side by side and my brother brought his YJ; we set up camp near Temple Mountain and took off for the maiden voyage to run Muddy Creek. Driving the pavement towards Goblin Valley the MJ ran great, the steering was great, ride was great, then I noticed the temp continuing to climb. I stopped at the entrance for the Ding and Dang hike with the temp reaching ~230F, popped the hood to find coolant spewing out of the Renix style coolant tank... barely hit a dirt road and I was broke ha. While it was cooling down we started poking and prodding around and found that the fan clutch was completely free spinning which shouldn't be happening with it this hot, it was shot. I didn't know it at the time, but the electrical fan on these things doesn't turn on unless the A/C is on or the temp on the cool side of the radiator gets above ~230F. My family went ahead, and my wife and I limped the MJ back to camp to work on it for the next day. Once I got to camp I unplugged the electrical fan and wired it straight to the battery with a switch all zip tied neatly under the hood, I'd have to pop the hood everytime to turn it on or off but good enough for the weekend. My dad found some plumbers tape in the camper and we removed one bolt from the clutch side and one bold from the fan side and tied the two together. Did a sunset trial run and everything was running good, but then the damn temperature started rising again, I pulled off the side of the trail to find some idiot (me) didn't replace the cap on the coolant reservoir, I'd boiled out a ton of coolant but luckily the cap was still sitting there under the hood. Filled it up with water and what little antifreeze I had and limped back to camp.

Day 2 I filled/burped/etc. the coolant system and replaced the cap. We then took off to run Behind the Reef, put about 60 offroad miles on the MJ and it ran cool/great the entire time. The challenge/drive was super fun, wheeling a manual on 33s and picking your way through spots you'd just run over in a buggy was awesome. My wife was a fan and multiple times said it was much more comfortable than the buggy.

One of the coolest parts of the ride - we were in the "wild horse canyon/flats" area and from my left we see come busting over the hill about 20 beautiful wild horses. It was something out of a movie, they ran up alongside us and right in front of us across the trail. We got some rough video, but it was awesome.

It was windy and rainy both nights we were there, but Saturday night was wild. Woke up to the tent laying overtop of us, wind howling and raining like mad, my wife, doggo, and I abandoned the tent and spent the rest of the night in the truck.

Overall a great trip and successful shake down.

A few more pictures from the weekend.













I've already replaced the fan clutch and will be replacing the thermostat tonight, then back to the list buttoning other stuff up. Hope to drive it a lot for the next week and pass emissions in the near future.

 

[crosbike]

Im glad your comanche is up and running with just a few slight hiccups. I look forward to more trip reports to motivate me to get mine done

 

[Thursty]

I love the drive out to Muddy Creek/Tomsich Butte. The wild horse sighting would’ve been awesome! Glad the Comanche only had minor issues.

 

[Gawynz]

It's cold, shop isn't heated, and I've been lazy delaying working on this thing... but back to it. I got an emissions test prior to SRS and failed. Replaced a bunch of vacuum hoses, valves, sensors, whatever and still failed emissions a few days ago; mechanic said there was a bad leak at the exhaust manifold which is the only place there could be a leak given that the exhaust from the manifold back is new. Last couple nights I pulled apart the drivers side of the engine bay and I think I've found my problem... If you look at the bottom left (in the pic below) you'll see a stud from the cyclinder head that holds the exhaust manifold on, there should be another one on the back side in the bottom right of the picture. The stud on the back end isn't missing, it's been twisted off inside the head and I can't get to it with an extractor. Looks like there may have been many leaks from the gasket, but you can see the very different color on the back side where the stud/nut was missing.

Long story short, MJ for sale.

Just kidding, not sure what to do. Pull the head, try an extractor or weld a nut to it and get it out. At this point just pull the engine and rebuild. Pull the engine and swap a 5.3 ha.

I'm thinking maybe I can weld a nut to it with it in the truck as it sits, but it's tight. As always, open to advice.

 

[Gravy]

I would feel pretty confident about welding a nut on there. Peen around it. Repeat until the broken stud is out. I broke one on my 1999 about 15 years ago when I was swapping a cracked exhaust manifold and we did this.

Also easy time to replace that wasted motor mount 😀

 

[Gawynz]

Also easy time to replace that wasted motor mount 😀

I knew someone would call that out, you win! ha. Thanks for the advice.

 

[Gawynz]

So follow on question - The stud broke below the surface, any tricks to making sure that while I build up the stud I don't weld the stud to the head?

 

[Herzog]

So follow on question - The stud broke below the surface, any tricks to making sure that while I build up the stud I don't weld the stud to the head?

Probably easier said than done, but can you use some kind of small thin wall tubing as a guide to build up some weld then attach a nut... Already looks like a huge pain to get in that position.

 

[N-Smooth]

Pray...?

Make a sacrifice to the broken studs Gods?

 

[Gawynz]

I tried to use an aluminum tube to protect the weld from the head but could get it to fit with any room to weld a decent thickness.

Pray...?

Make a sacrifice to the broken studs Gods?

I built an alter out of old MJ parts, stole and sacrificed a neighbors goat, then just said screw it and gave it a shot. First nut I welded on loosened the bolt (I think) but twisted off. Welded on a second and then heated, PB blasted, peened, and slowly worked back and forth repeating until it came out! Thanks guys.





Also, from the tools thread on this forum I picked up one of these silicone trays off Amazon and they're great.

 

[Gravy]

That is so satisfying!

 

[Gawynz]

That is so satisfying!

So satisfying. I don't know what came over me but when I got that stud out I immediately took my pants off, jumped up on the bumper of the jeep and smashed two beers together overhead stone cold syle...

 

[Gawynz]

Took me forever to get a intake/exhaust manifold gasket, the first two shipped to me were bent but was finally able to get one ordered to a local store. Got everything I'll say 80% cleaned up and not greasy and put it back together. There was a small crack in the exhaust manifold so I ground it out and welded. The PO replaced the power steering pump, I didn't notices until I was putting everything back together but one of the bolt holes that mounts the pump bracket to the engine was stripped in the aluminum intake manifold; installed a helicoil and got it fixed. Put everything back together last night and it fired right up, if I don't pass emissions now I don't know what to do.

 

[The_Lobbster]

This wouldn't exactly be honest......but.....you could ask to register it as diesel. It would then be exempt. I registered my comanche as diesel because I was going to TDI swap it. And I also had my TDI samurai registered as diesel. Lady at the dmv asked for my emissions once and I pointed out it was registered as diesel, and therefore exempt, and that was that.

Slap a couple "turbodiesel" ebay badges on the side for added effect.

 

[Herzog]

This wouldn't exactly be honest......but.....you could ask to register it as diesel. It would then be exempt. I registered my comanche as diesel because I was going to TDI swap it. And I also had my TDI samurai registered as diesel. Lady at the dmv asked for my emissions once and I pointed out it was registered as diesel, and therefore exempt, and that was that.

Slap a couple "turbodiesel" ebay badges on the side for added effect.

Since it is a 4.0L, it is going to be burning some oil so it's not too dishonest.

 

[Gawynz]

Failed emissions again today, I'm about to list this damn thing for 2x what it's worth and just see if it sells. It did improve though, last test their machine couldn't even get a reading for any of these metrics so the exhaust leaks were causing problems (I guess?). This time around here are the results, failing on CO% which means it's running rich.



It cracks me up that they tell me how much I have to spend in repairs.

So the entire exhaust is brand new, air filter is new, O2 sensor is new, engine coolant temp sensors are new, spark plugs and wires are new, the entire vacuum manifold cluster/EGR is new, fuel pump is new, tested with fresh gas, injectors I robbed out of a junk yard as described earlier in this thread (supposedly an "upgrade"), compression test is on the bottom end of the range but "ok". My plan is to check/replace the MAP sensor tube, replace the MAP sensor, replace the throttle positioning sensor, clean the throttle body, replace the injectors w/ stock. If that doesn't work, burn it to the ground.

Any other ideas other than registering it as a diesel (it was a creative idea that I do appreciate ha)?

 

[N-Smooth]

Failed emissions again today, I'm about to list this damn thing for 2x what it's worth and just see if it sells. It did improve though, last test their machine couldn't even get a reading for any of these metrics so the exhaust leaks were causing problems (I guess?). This time around here are the results, failing on CO% which means it's running rich.

View attachment 170935

It cracks me up that they tell me how much I have to spend in repairs.

So the entire exhaust is brand new, air filter is new, O2 sensor is new, engine coolant temp sensors are new, spark plugs and wires are new, the entire vacuum manifold cluster/EGR is new, fuel pump is new, tested with fresh gas, injectors I robbed out of a junk yard as described earlier in this thread (supposedly an "upgrade"), compression test is on the bottom end of the range but "ok". My plan is to check/replace the MAP sensor tube, replace the MAP sensor, replace the throttle positioning sensor, clean the throttle body, replace the injectors w/ stock. If that doesn't work, burn it to the ground.

Any other ideas other than registering it as a diesel (it was a creative idea that I do appreciate ha)?

Register it somewhere that doesn't require emissions. Done.

Edit: or vintage...?

 

[Trate D]

These have an 02 sensor relay under the hood that are known to stick giving full voltage causing a rich condition. I’d swap that out and re-test.