88 Comanche SporTruck Project Daily

[Jeepzahn]

Finally joined the Comanche club a couple months ago.

This is a 1988 4.0 5-speed 4x4 with 180k on the odo. Exactly, what I had been searching for... a shortbed, 4wd, manual with a 4.0.

 

Currently, I am wrestling with some electrical gremlins and goblins. Learning Renix has been interesting, to say the least.

Not on the road just yet but, once I am finished sorting out the wiring it should be good to go.

 

 

 

 

[Jeepzahn]

Came across a cheap front clip for a white XJ, so I nabbed that and swapped those panels on. Eventually, I will put the Comanche emblems on, but I think ill leave it a Cherokee truck for now.

The factory fenders were pretty bent up, and the factory header panel was cracked, so I was pretty stoked to find all that together for cheap on Craigslist.

The center grille piece isn't exactly correct, but it will do for now as well.

 

[Jeepzahn]

can't wait to get this thing on the road... but, still chipping away in the meantime. Finally got the instrument panel to light up, and all exterior lights are finally functional.

Adding grounds, and more grounds. Thankful for cruiser54 for his extremely helpful wealth of knowledge and tips for the Renix. Cheers!

 

 

 

 

 

Sorry, these pictures are probably kind of boring.

I have soldered in a few grounds in other areas as well... its only helping, thats for sure.

I think I need to replace the TPS, and possibly the injectors as there was some bad gas in this thing and it sat a bit.

Other than a slow start, it seems to idle well... but, doesn't like to take fuel.

 

 

 

[Jeepzahn]

Alright, I removed the factory injectors yesterday, and they look pretty horrible. One of the o-rings and a washer was actually still in a rail port when I removed them.

I installed the appropriate Volvo injectors with new o-rings. Also a new fuel pressure regulator and seal. That seemed to solve most of my fuel delivery issues, however I do not think I am getting enough pressure at the rail. Key-on/engine off: pressure jumps up to around 30 psi and then sits at 10psi.. While idling the pressure sits between 27-31 psi, and does not change when I remove the vacuum line. Idles great, sounds great... surges while driving when trying to give it fuel. Any suggestions would be greatly appreciated!

In the meantime, I have fixed even more grounds... soldered the sensor grounds before the C101 connector.

 

Horrible factory splice:

 

The factory driver's side turn signal socket was broken, and I happened to have a harness from a later XJ, so I tried splicing in the different style. Works great, and the socket is exact match for the light assembly:

 

Factory injectors:

 

Also, went ahead and threaded the throttle body for a better MAP sensor vacuum connection. The little rubber plug on mine wasn't helping much.

[Ωhm]

Key on will cycle fuel pump 3-5 seconds with engine off (no crank). 27-31 psi is a good pressure. Pressure should hold and slowly bleed down taking a hour or more. Suspect check valve on fuel pump or leaky injector. As for no change in fuel pressure reading with vacuum hose removed, check hose or the manifold inlet nipple for blockage. Possible faulty new fuel regulator.

[Jeepzahn]

23 hours ago, Ωhm said:

Key on will cycle fuel pump 3-5 seconds with engine off (no crank). 27-31 psi is a good pressure. Pressure should hold and slowly bleed down taking a hour or more. Suspect check valve on fuel pump or leaky injector. As for no change in fuel pressure reading with vacuum hose removed, check hose or the manifold inlet nipple for blockage. Possible faulty new fuel regulator.

 

Thank you for the feedback Ωhm!

I am most likely just going to drop the tank this weekend and visually inspect everything. I am going to just end up putting in a new pump if that is in fact what it is... might do it anyway. I figure if i already have it dropped and i'm in there. This pump is very loud as well (with or without the ballast resistor), and who knows how much life is left in it. If its stock, I would say not much longer..

[Jeepzahn]

Jeep really is an acronym for "Just Empty Every Pocket."

However, there are much worse things to spend my money on than Jeeps.

 

Anyway, I was under the truck looking everything over before pulling the pump and/or dropping the tank. I noticed a weird large flake on the bottom of the tank, so like a complete idiot I picked it a little.. Sure enough, it was some sort of patch the previous owner must of placed on it to cover two little rust holes. Made for an easy drain of the tank at least.

 

Flash forward a bit. New tank and Bosch pump are in, and everything seems to be working great. I did manage to break the little sending unit switch housing though, but i found one that was identical in a YJ tank at the shop. I went ahead and swapped it and it seems to be working... the fuel gauge didnt register at first, but when I put another couple gallons in, the needle rose.. hopefully when I fill the tank more it will continue to work. YJ tanks are certainly more plentiful, so it would be good to know as a possible candidate for a sending unit swap.

 

The Bosch pump is SUPER quiet, I can barely hear it at all. The pressure at the rail now is perfect, and with the regulator vacuum line removed as well.

It still felt strangely boggy in low rpm in first, and hard to have a consistent throttle in low speed. Today, I removed the EGR line and capped it... that seemed to have helped A LOT with that, and maybe the final issue. Capping the EGR also seemed to alleviate the intake backfire I was getting occasionally as well.

 

Truck is still not tagged yet, but hopefully all that will be sorted out in the next couple weeks. Looking forward to what is to come with this tough little truck.

 

 

Took a little hammering to get the tailgate to work... it'll do for now! 

 

 

 

 

 

[Jeepzahn]

Old tank and pump/sending unit.

 

Bosch pump installed. Factory housing and floater arm. Only thing I changed, besides the pump, was the little brown sending unit box. I broke the original's connection, and it was all too brittle to solder the tab back on. This one is out of a YJ tank (not sure the year) and it seems to work so far.

 

Also, the cable that moves the seat slider was super slacked out and was driving me nuts. The seat was always stuck way too far forward. Quite the abandoned mouse party under the seat..

 

Fixed... but, could definitely stand for more cleaning..

 

 

[Jeepzahn]

Ive been using the truck as a daily now and its been wonderful!

I still have work to do, and would like to lift it a few inches to fit 31s. I am planning on swapping in some WJ lower control arms as well.

I have an opportunity for a set of 5 15x8 Canyon wheels from an early YJ, so I am planning on using those with some 31x10.50s. It would also give me a spare. I don't have one for the truck now.

 

I disconnected and capped my EGR as it was causing throttle stuttering issues.. haven't addressed that yet, but I figure it's fine capped for now.

 

The truck had a grime on it that I couldn't wash off, so I tried Comet and a sponge and it did wonders. No more stained paint.

 

 

 

 

 

 

I slept in the back of it Saturday night under the stars. No complaints here so far. Excited to get it a little higher though, and new shocks (fronts are shot now).

 

 

 

 

 

 

 

[DirtyComanche]

Looking good.

 

Interesting intake mod there, was there a reason to not use a factory one?

 

I love your rubber floor...  Wish mine had one.

[SatiricalHen]

Could you take a picture of the “egr cap” I’m having a stuttering/stumbling issue and I can’t seem to get it resolved. I’m swapping in some new injectors this weekend, but would like to try capping the egr too and see if it helps any


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[DirtyComanche]

20 hours ago, SatiricalHen said:

Could you take a picture of the “egr cap” I’m having a stuttering/stumbling issue and I can’t seem to get it resolved. I’m swapping in some new injectors this weekend, but would like to try capping the egr too and see if it helps any

 

I'm not him, but if you're sure you don't want it you can tap the hole in the intake to 3/8 (IIRC) NPT and just thread a pipe plug into it.

[Jeepzahn]

On 3/6/2018 at 9:59 PM, DirtyComanche said:

Looking good.

 

Interesting intake mod there, was there a reason to not use a factory one?

 

I love your rubber floor...  Wish mine had one.

 

Thanks man!

 

So, the intake.. when I got the truck, the factory rubber intake tube was ripped where it connects to the throttle body. The PO had tried to duct tape it together.

I couldn't find a way to re-use it, so I found a Spectre brand TB adapter on amazon for the flange. The tube came from the auto store in town. I wasn't sure what to do really, but this works. I need to find a different type of tube, as this is too high where it bends and its pressing into the hood when its shut. I also hate the way it looks, reminds me of cheap dryer or shopvac hose.

 

Rubber floor is definitely great too. I want that in every vehicle I own!

[Jeepzahn]

On 3/6/2018 at 11:41 PM, SatiricalHen said:

Could you take a picture of the “egr cap” I’m having a stuttering/stumbling issue and I can’t seem to get it resolved. I’m swapping in some new injectors this weekend, but would like to try capping the egr too and see if it helps any


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Here is my EGR capped. The black plastic piece is the transducer, I don't believe capping that even matters, so ignore that.

The EGR is the capped part below it.

 

It is on the manifold side of the motor, beneath the throttle body. It's Exhaust Gas Recirculation, so look down by the exhaust manifold

 

What else is your vehicle doing? What have you ruled out already as a potential culprit for the stutter?

Hope the pictures help!

 

 

[SatiricalHen]

 
I'm not him, but if you're sure you don't want it you can tap the hole in the intake to 3/8 (IIRC) NPT and just thread a pipe plug into it.

Eventually I’ll put a 99 intake and newer head in, so there’s no place for egr down the road, but I’d like to at least temporarily test it and see if it does anything.


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[SatiricalHen]

 
What else is your vehicle doing? What have you ruled out already as a potential culprit for the stutter?
Hope the pictures help!
 
 

I’ve replace the fuel filter, new wires, cap and rotor, removed the cat, it blew the muffler up (so for now it’s straight pipe till I fix it), cleaned tb, cleaned iac, adjusted tps, new air filter, refreshed grounds and went through most of cruisers renix tips and that’s all I can think of right now.


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[SatiricalHen]

Just thought I’d come back with the solution even though this isn’t my thread. Unplugged the IAT and it runs perfect. Just need to get a replacement for it now.


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[Jeepzahn]

On 3/13/2018 at 12:09 AM, SatiricalHen said:

Just thought I’d come back with the solution even though this isn’t my thread. Unplugged the IAT and it runs perfect. Just need to get a replacement for it now.


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Awesome man! Congrats on figuring out that issue. Good luck finding an IAT, or do you know what you are going to use? I think replacements are hard to find, but if you are going to switch to the newer intake soon then I wouldn't worry with it until after that. Does the disconnected IAT seem to affect your gas mileage?

 

Cheers 

[DirtyComanche]

The GM IAT should work, you just need to make a pigtail to plug it in IIRC.  It's just a GM sensor under another P/N to make life confusing, basically, many of the Renix sensors are.

[SatiricalHen]

 
Awesome man! Congrats on figuring out that issue. Good luck finding an IAT, or do you know what you are going to use? I think replacements are hard to find, but if you are going to switch to the newer intake soon then I wouldn't worry with it until after that. Does the disconnected IAT seem to affect your gas mileage?
 
Cheers 

You can use a GM sensor or find a used one. That’s about the options we have available. Even with the new intake I’ll be using renix sensors so I’ll need it. If I did the math right I got 17 mpg this fill up, but I also did injectors and spark plugs at the same time so that probably did a good bit too. Usually get around 15ish I think.


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[Jeepzahn]

7 hours ago, SatiricalHen said:

You can use a GM sensor or find a used one. That’s about the options we have available. Even with the new intake I’ll be using renix sensors so I’ll need it. If I did the math right I got 17 mpg this fill up, but I also did injectors and spark plugs at the same time so that probably did a good bit too. Usually get around 15ish I think.


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Okay great... I am sure I will have to replace mine at some point. That is great you are getting 17mpg! I know most modern cars get much better mileage than we are talking here, but I still get ecstatic about the little things. Hell, my 2002 WJ gets about 15, so thats what i'm used to. Which injectors did you use?

I've only had a few fill-ups since I got my Comanche on the road, but so far, I've been averaging over 20 mpg, which I think is crazy considering I live in the mountains and rarely use a highway. That is with Volvo injectors and a recent full tune-up (plugs, wires, cap/rotor), not to mention a new fuel pump, pressure regulator and TPS.

 

Unfortunately, it failed to start Friday afternoon, which I narrowed down to my starter relay. I can start it by jumping the relay straight to the battery.

Anyone have any suggestions on which starter relay to seek out? No one carries them in stock around here.. still need to check NAPA tomorrow, but its unlikely they will stock one.

 

[SatiricalHen]

 
Okay great... I am sure I will have to replace mine at some point. That is great you are getting 17mpg! I know most modern cars get much better mileage than we are talking here, but I still get ecstatic about the little things. Hell, my 2002 WJ gets about 15, so thats what i'm used to. Which injectors did you use?
I've only had a few fill-ups since I got my Comanche on the road, but so far, I've been averaging over 20 mpg, which I think is crazy considering I live in the mountains and rarely use a highway. That is with Volvo injectors and a recent full tune-up (plugs, wires, cap/rotor), not to mention a new fuel pump, pressure regulator and TPS.
 
Unfortunately, it failed to start Friday afternoon, which I narrowed down to my starter relay. I can start it by jumping the relay straight to the battery.
Anyone have any suggestions on which starter relay to seek out? No one carries them in stock around here.. still need to check NAPA tomorrow, but its unlikely they will stock one.
 

I actually have a spare starter relay I pulled from a junkyard Cherokee, so I can’t tell you where to get one in stores. I’ve done plugs, cap, rotor, and fuel filter. I have a feeling my pump is going out so I need to replace it sometime, probably wouldn’t be a terrible idea to do the pressure regulator while I’m there and have a full fresh system. I put in some refurbished 746 injectors. Something is still up with it since it’s more gutless than my 4wd cherokee with 5.5” of lift and 35s. Gets better mileage, but has no power. The Cherokee gets under 14 mpg usually. What fuel pump did you go with?


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[Jeepzahn]

2 hours ago, SatiricalHen said:

I actually have a spare starter relay I pulled from a junkyard Cherokee, so I can’t tell you where to get one in stores. I’ve done plugs, cap, rotor, and fuel filter. I have a feeling my pump is going out so I need to replace it sometime, probably wouldn’t be a terrible idea to do the pressure regulator while I’m there and have a full fresh system. I put in some refurbished 746 injectors. Something is still up with it since it’s more gutless than my 4wd cherokee with 5.5” of lift and 35s. Gets better mileage, but has no power. The Cherokee gets under 14 mpg usually. What fuel pump did you go with?


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I ordered a Bosch unit through Amazon for around $60. It's Bosch 69302 Original Equipment Replacement. It solved my pressure issues at the rail, and it is VERY quiet... I really can't hear it unless I get under the tank and listen. My old fuel pump was really loud also. If you go with that Bosch unit, just realize it is smaller than OEM, so you have to use the included adaptors and modify the mount a little to make it work. It didn't come with instructions, but it was simple to figure out, and there are a couple threads pertaining to that pump on here and other forums.

 

Have you checked your MAP sensor on the Comanche? I recommend doing Cruiser's tip of threading the throttle body and using a brass carb fitting for the MAP connection if you haven't done that yet. It's pretty cheap to do, especially if you already have access to a threading tool.

[SatiricalHen]

 
I ordered a Bosch unit through Amazon for around $60. It's Bosch 69302 Original Equipment Replacement. It solved my pressure issues at the rail, and it is VERY quiet... I really can't hear it unless I get under the tank and listen. My old fuel pump was really loud also. If you go with that Bosch unit, just realize it is smaller than OEM, so you have to use the included adaptors and modify the mount a little to make it work. It didn't come with instructions, but it was simple to figure out, and there are a couple threads pertaining to that pump on here and other forums.
 
Have you checked your MAP sensor on the Comanche? I recommend doing Cruiser's tip of threading the throttle body and using a brass carb fitting for the MAP connection if you haven't done that yet. It's pretty cheap to do, especially if you already have access to a threading tool.

I can hear my fuel pump over the exhaust and currently the truck doesn’t have a muffler. It’s LOUD just gets louder as you drive. The vacuum line to the MAP is fine, haven’t checked the actual readings though. When the vacuum line is unhook it runs like garbage though so it’s doing something.


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[Jeepzahn]

It's been a while since i've posted, but seems like a good time for an update post after a productive day.

The truck has been doing great, although I have had to repair some things over the last couple months.

 

Here are some photos from the last few months. It's a slow process, but this truck is becoming more and more enjoyable and our relationship continues to grow!

 

 

 

 

 

Developed shifting issues... ruled it out to be the master cylinder and slave, and I could hear the throw-out bearing. Ended up doing the clutch while I was in there, and replaced all fluids, with the exception of cooling and brake, while I had it up in the air.

 

 

 

Ran into further problems with excess play in the clutch pedal. Turns out the assembly stud was half-way worn through. Anyone else experience this?  Could save a lot of heartache with clutch master engagement issues... I had someone weld up the gap, and I used a greased metal bushing as a spacer to take out the slack. Hope this helps others..

 

I will definitely be throwing in an AX-15 the next go around. I am going to start sourcing one soon.