86 Diesel MJ to VW TDI conversion

[johnj92131]

That starter solenoid relay turned out to be just the first of many electrical issues.  All caused by the most common Jeep electrical issues:  Bad connections after close to 30 years.  Once the engine was running, we discovered nothing electrical in the cab seemed to be working.  More importantly, none of the tail lights/brake lights worked.  After a bunch of rechecking splices and connections, Matt found the problem at the fuse panel inside the cab.  All the fuses and  connections were corroded.  So all the fuses were tossed and the connections were cleaned.  Once this was done we had power to the cab and the tail lights.  The fan blower motor still did not function but had 12 volts to the motor.  Seems the 30 year old motor is shot.

 

Next the tach did not work. After some research, Matt got it working by picking up the W terminal from the alternator.  The tack was now reading 1100 RPM and the VW computer was reporting 900 RPM.  This was fixed by adjusting the Comanche tach (had to pull the tach from the cluster to access the adjustment pot on the tach). Now the Comanche tach was reading 900 RPM.

 

By now it was 2 a.m. on Thursday night/Friday morning when Matt finally quit for the night.

[johnj92131]

One issue that I have to say a big Thank You to Automan2164 here on the Comanche Club.

 

We had problems trying to find the water temperature sensor on the old Renault engine.  So I posted a request for help here on the Comanche Club:

 

Rob gave us all the answers and Pictures we needed to find the old temperature sensor!  A big Thank You to Rob!  

 

With that help, we found the old sensor. Matt fabricated a bung, welded it into the water lines and we had a sensor.

But we ran into another issue. The wire that came off the original sensor "Looked" green and there were several green wires on the other side of the engine bay. Turns out none of them match our original wire. So we pulled the wire back out of the cross body loom. Turned out the color was blue by the time we got to the other side of the engine bay. Oil, heat, and time had changed the wire color and fooled 4 of us who all check the wire color. That solved our water temp problem for a little while.  Turned out a few days later with the engine warmed up the old temperature sensor was not reading any heat.  So the old sensor is bad and will be replaced.

 

By 10:30 a.m. Friday it was time for me to leave the shop for a meeting in Plymouth, Michigan.

Several issues remained. The biggest was Reverse could not be engaged with the engine running. Boost was very erratic. Matt planned to change the N75 valve. There were a few smaller issues to be addressed.

By Sunday afternoon, I was back home in San Diego and the truck was still in Michigan. But I was very well pleased to see how close the truck is to being road worthy.

 

Here is a Monday afternoon progress update from Matt:
 

Bled the clutch more, everything seemed to be fine, went out for a drive today and by the end of the drive it was mushy again and couldn't engage reverse without shutting the truck off. I'm going to replace the master and hose.

Seems that everything that's original on the truck is just worn out/leaking/tired.

Jeep temp sending unit isn't reading right either so I'm going to replace that. Grounded connection and it goes right to max so the gauge and wiring are good.

Coolant also sprayed everywhere due to a bad cap on the radiator.

The oil pan gasket is also seeping so I'm going to do without the gasket and just silicone seal it like Mk4's are, I did the same on my ahu in my rabbit truck.

The alignment is also wayyyy off, it's toe'd out in the front badly. It's twitchy and all over the road.

I don't have a single good n75 here apparently so I'm going to grab also. They all are leaking vacuum out the vent port so boost control is all over the place.

Last bit of bad news, the left rear rim is bent like all hell. It has a good 1/4"-3/8" wobble in it spinning on the hoist.

Good news, tach works and i adjusted it to read correct 900prm at idle, heater valve operation works, and it has 5 miles on it now .

Matt likely means 5 kilometers on the truck - Originally sold in Canada, so metric speedometer/odometer. JJ

 

So now the thread is up to date with progress. 

 

 

__________________

 

[johnj92131]

Latest up dates:

Clutch is now working fine and holding. Salve cylinder and a hose were replaced.

New N75 installed and the tune is being dialed in.  (N75 controls the boost)

One more oil leak still to fix. Last one fixed was a leaking intermediate shaft seal. It was new, but still leaked.

Fuel sender works fine. Truck took 21.5 gallons in a 23.5 gallon tank. So he will be able to put some more miles on the truck now.

Rear springs are getting change out today. Putting in a good, clean used set of standard Comanche springs to replace the bastard pack that is in now. Guess I cheaped out on the springs!

Asked Matt to check the rear axle gear ratio for me.

I may have a driving video tomorrow.

Still need to send Matt the EGT gauge. He has the probe installed and wire into the cab.

 

Surprised to find that even the clock works!

__________________

[Minuit]

 

Can't wait to see it driving.

[johnj92131]

When I first started this project, I thought it would be a simple engine conversion. But I have come to realize I purchased a diesel title and a very real parts truck to restore.  My original budget guesstimate was $7500 to get it running properly. Proper restoration will be a good bit more cash and time.

[kansashogan]

Exactly what I said about the budget. Tack on many thousands more. I swear everything possible was worn out-no idea how the previous owner even drove it.  I am anxious to see your truck finished, kudos to you sir.

[johnj92131]

As promised - here is a short video of the truck now running under TDI power.  Take a good look at those speeds!  That little engine really moves the truck. 

 

Not REALLY as fast as it looks - Speeds are in KPH, not MPH.  Remember the truck was built for Canada.  But the tach is accurate  - so you do see the TDI engine turning 5000 rpm.  Also the factory Jeep boost gauge scale only goes to 15 psi.  The turbo on the TDI is tuned for about 25/26 psi.

 

Click on the link to see the YouTube video

 

https://youtu.be/mr3ThOyOhT8

 

 

 

 

[krustyballer16]

As promised - here is a short video of the truck now running under TDI power.  Take a good look at those speeds!  That little engine really moves the truck. 
 
Not REALLY as fast as it looks - Speeds are in KPH, not MPH.  Remember the truck was built for Canada.  But the tach is accurate  - so you do see the TDI engine turning 5000 rpm.  Also the factory Jeep boost gauge scale only goes to 15 psi.  The turbo on the TDI is tuned for about 25/26 psi.
 
Click on the link to see the YouTube video
 

 
 
 
 

It looks like it moves a little quicker than my Cummins. And smoother. 2700rpms is all mine has also.
I haven't read the whole thread but I like how you got all the gauges to work! Awesome. You need to get it home before February so i can see it!

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[HOrnbrod]

1 hour ago, johnj92131 said:

 Also the factory Jeep boost gauge scale only goes to 15 psi.  The turbo on the TDI is tuned for about 25/26 psi.

 

Sounds great John. 

 

You need one of these panels now, only with a 0-60 boost gauge.

 

[Jeep Driver]

Very cool!

[DirtyComanche]

Awesome you got this thing going!  It really seems like a great swap and I look forward to reading more updates as the inevitable little things all get worked out.

[johnj92131]

Long time and no update for a good reason...  Truck is still in Michigan and I simply have not had the time to go back and get it home.  Now with winter weather started - No Way is this California boy going to pick it up in the snow and cold weather.  For one thing, the heater fan does not work.  It has power, but will not run.  So right now it looks like I will not get it home till next March/April.  Unless I decide to have the truck shipped home for about $1200 from northern Michigan to San Diego.

 

 

[krustyballer16]

Long time and no update for a good reason...  Truck is still in Michigan and I simply have not had the time to go back and get it home.  Now with winter weather started - No Way is this California boy going to pick it up in the snow and cold weather.  For one thing, the heater fan does not work.  It has power, but will not run.  So right now it looks like I will not get it home till next March/April.  Unless I decide to have the truck shipped home for about $1200 from northern Michigan to San Diego.
 
 

I'm coming your way in February with an empty trailer...

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[johnj92131]

Man, you are the Devil!!!

 

Been thinking about a winter trip to the Detroit Auto Show in late January with a possible side trip to upper Michigan if the weather was not too bad.    Would have to get the truck from upper Michigan to Indiana.  How far are you from the Mackanak Bridge?  Maybe 600 miles?

[Honcho]

hello I had that truck for about a year sold it to the guy in Victoria for $700 I traded a wagoneer for it . it had the head off was warped from being overheated I took the head from the spare engine put that on but was cracked still drove it to and from work for 6 months put about 3000km on it then gave it to my son for his fist vehicle that did not go so well the cracked head got much worse and after a couple tows home that was enough was able to about 30mpg when it was working good power was not disappointing I tried to post some pics I have of it but can't get it to work good luck with the truck.

[johnj92131]

Honcho,

 

Drop me an email at:  johnj92131@yahoo.com

 

Would love to see the pictures.  Thanks for noticing the truck.  We also found one cylinder liner was cracked (in addition to the cracked  cylinder heads.

[krustyballer16]

Coming down to indiana!

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[johnj92131]

Well the TDI Comanche made it to San Diego on March 10.
 

 Another Comanche Club (Shelbyluv) member was going to San Diego to pick up a camper shell for his Dodge and offered to deliver the truck right to my door! How is that for help!!

The left front tire was almost flat from a slow leak and the clutch was not releasing well to change gears. But it is finally in California and we have started the registration process by going to the Auto Club. Only to find out that because the truck is from British Columbia I can only register it by making an appointment with the California DMV. The first appointment time was 2 weeks out, so the car sat in the driveway till then.

The registration process was fairly simple and I had all the documents required, so I walked out with a temporary registration and the DMV got a $186 check for use tax, current registration and about 15 different misc. "fees". My only surprise was that because it is a pickup and registered as a commercial vehicle, I had to get a certified weight on the truck. My Briitish Columbia registration listed the weight as 1393 kg or 3071lbs, but not good enough for the DMV.  So a trip to a Certified Scale and $15 later I have the Certified Weight of 3180 lbs, that is with 23 gallons of diesel in the fuel tank. Just one more trip back to the DMV to turn in my paperwork and I will get a fresh set of California plates. Also got the truck added to my insurance policy today. 

 

Since the truck's future license fees will depend in part on the certified weight I turn in to the the DMV, I am going to reweigh the truck with just 2 or 3 gallons of fuel.  That should drop the weight by about 140 lbs

More about the clutch issue and it's solution in the next post

[johnj92131]

We noticed the clutch problem the first time we moved the truck off the trailer on to the driveway.

Matt said the clutch had been fine at his place. Brandon (krustyballer) also told me the clutch had been fine both when he picked up the truck in Michigan and when he dropped it of at 29 Palms, Ca. But by the time the tuck got to San Diego we noticed the problem about 3 weeks later.

Whitbread was going to be in Southern California for Easter, so we agreed he would check it out when he got here. Last Thursday we met half way between where he was staying and San Diego. After bleeding the clutch, Matt noticed the clutch fluid was discolored and had some aluminum particles suspended in it. His diagnosis: A bad clutch cylinder out of the box - scraping the bore of the cylinder wall. So Matt called his NAPA supplier in Michigan who agreed to a warranted replacement for the clutch master cylinder and had it delivered to my local NAPA store for me to pick up on Saturday. Here is a picture of the new parts.  Clutch Master Cylinder on the right:

 

 

 

The other two items in the picture are a new, larger power steering pump idler pulley and a longer belt to go around the pulley.

 

Matt came down to San Diego on Tuesday and installed the new/replacement master cylinder, installed the revised pulley and belt.  Also finished up adjusting the turbo actuator arm length.  Clutch seems fine now, but I plan on putting some miles on it before we declare the problem solved.

 

Next item on the list was that slow leaking front tire.  I took the truck to Discount Tire this afternoon to get the leak fixed, because the tires on the truck look quite good.  Turns out the tires are 18 years old - made in the year 2000!

 

So replacing the tires and figuring out what wheels I want on the truck just moved way up to the head of the line. Not exactly what I planned. But it needs to be done.

Stock steel wheels were 15 x 6 wide. Optional were 15 x 7 wheels and in later years, the 15 x 7 size was standard. Any wheel that fits the 86 to 2001 Jeep Cherokee (XJ) will work. Just a matter of deciding on a wheel style.

 

My first thought is to go with the 5 star aluminum wheels that were optional on my 91 Comanche.  That would let me sway tires and wheels between the 2 trucks at will.

 

The second thought is to stay with the 86 steel "rally wheels", even if they are narrower - hey - it is the cheapest thing to do.

 

Any input would be appreciated.

 

 

 

 

[krustyballer16]

Why a bigger pulley?

If you want, I can post the ten million pictures I took of your truck while i had it...some comparison videos too...

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[johnj92131]

The original plan was to go with an electric power steering pump from a Volvo.  But after installing the electric pump, Matt found the pump was randomly and momentarily failing while on the road.  So in January, he installed a stock power steering pump from a 2000+ Jetta with a small idler pulley.  See picture:

 

 

 

Several TDI Club members posted their poor life span experience with the small idler pulley.  So Matt decided to make a new bracket with the larger pulley as a proactive measure after you picked up the truck.

 

Brandon - Please do feel free to post any pictures you have.  Comparison Videos would be great!  Not very often do we have the chance to see 2 different Diesel Comanche conversions side by side.

 

 

[HOrnbrod]

10 hours ago, johnj92131 said:

So replacing the tires and figuring out what wheels I want on the truck just moved way up to the head of the line. Not exactly what I planned. But it needs to be done.

Stock steel wheels were 15 x 6 wide. Optional were 15 x 7 wheels and in later years, the 15 x 7 size was standard. Any wheel that fits the 86 to 2001 Jeep Cherokee (XJ) will work. Just a matter of deciding on a wheel style.

 

Any input would be appreciated.

 

15x7 Turbine 10-spokes w. machined face and caps.

[johnj92131]

Have not seen any Turbine wheels for sale in some years.  They sure would be model year correct.     Got a price quote to sand blast and powder coat a set of 5 steel OEM rally wheels at $200.  Figured $200 would be better spent on aluminum wheels.

[HOrnbrod]

You can get them remanufactured LN for ~75/ea. + shipping. I got a set HERE. They were perfect - even had the inside surface between the spokes painted to my body color. Look for p/n 52000025. They have the caps too.

[Pete M]

there's a wheel guide in the link in my signature.   

 

tied with turbines as my favorite Jeep rims: the 15x8 TJ Canyons   (15x7 if they came on ZJs)