Jeep CJ-7 6.5L TD Conversion

[Rafedial1]

I am the owner of a 1994 Chevrolet C2500 truck with the 6.5L TD and 4L80E 2WD. I have started to swap the drivetrain into a Jeep CJ-7. I currently have all components removed from the donor vehicle and started making the motor/trans mounts (engine/trans are in the Jeep). I have heard mixed opinions from some local diesel enthusiasts about this subject. Looking for any info you have to offer as I am stuck between a rock and a harder rock about all this. Heard this was the best place to come for info.



1) I am removing my A/C compressor and replacing with an idler pulley, because it never really gets past 90 degrees around here. Any codes get thrown without A/C hooked up? Obviously a belt length change is needed.



2) I going to remove the Vacuum pump just to simplify my setup and eliminate problems in the future. So, I would need the mechanical turbo boost controller and what else? Does the mechanical one react as quickly (bring on boost) as the vacuum controlled system? If a vehicle weighs less overall (truck v. Jeep) would it take more relative time to bring on full boost compared to the vacuum system? Any Computer Codes to worry about?



3) Looking to do a gear/tire size change. Is there a way to calibrate this to get an accurate speed on the gauge cluster/computer, because I am going to try to use the gauge cluster out of the truck in the Jeep. Is this possible?

I guess I have to use the entire interior wiring and engine wiring from the truck (already removed) to use the gauge cluster correct? There are so many wires I am overwhelmed!!!!



4) If a modified ECM/computer is needed for conversion, can it be reprogrammed in the future if more mods are done?


IF ALL ELSE FAILS........
5) I have the DB2 Conversion Guide that I will eventually do, after the Jeep is running OR would it be possible to completely eliminate the Computer and ALL Wiring, start over and just use the simplest wiring setup? I would obviously lose 4L80E control. I am looking to make this engine run as simply and reliably as possible.



For example: DB2 Marine 250 or 300HP+lines, Manual Boost Controller, Marine Injectors, WIRING: Fuel Shutoff, E-Lift Pump, Manual Glow Plug Controller, PCS 4L80E computer and harness, Cable Throttle, And a whole bunch of aftermarket gauges (Oil pressure/Temp, Volts, Water Temp, Lift Pump Pressure, 20 GAL Fuel Cell w/0-90 Ohm Sender, Tachometer??????, Speedometer?????, etc.) Obviously more difficult, yet most reliable.


How do you Diesel Conversion guys do it?


-Cody

[arveetek]

Although it's been done successfully, I would not for one inkling of a moment consider using the electronic DS4 pump in a conversion, especially into a CJ. I would dump that electronic pump and all associated components, and go with a mechanical DB2 pump. All you need then is one wire to hold open the fuel solenoid to keep the engine running, and then a few wires for the glow plug system. Get a stand-alone computer for the tranny, such as from a 93 model 6.5L truck or aftermarket version, or use a TH700R4 that needs nothing but one wire for the TC lock-up functions.

I wouldn't bother with upgrading to a marine pump. They're expensive and I don't think you'd ever use that much power in such a light vehicle. The base engine for your CJ was a 2.5L 4-cylinder, so a 6.5L V-8 turbo diesel, even stock, will rock your world!

Again, my advice is dump the DS4 and run run run!!! They're okay in a stock vehicle, but I would never go through that much work to retrofit it into another vehicle, especially a CJ. Also, the '94 models had extra quirks that are not very desirable.

I've done two diesel conversions and am getting ready to start my third, by swapping in a 6.2L into a 93 Jeep Grand Cherokee, to use as an off-road toy.

Casey

[Rafedial1]

Thanks for the response Casey.

DB2 injection seems like the way to go. But I have decided since it doesn't fit into my budget or time frame, I am going to use the DS4 5068 pump that came on the truck. I really want to keep the OBD1 monitoring also and all other component parameters. The PCS Brand auto trans controllers are too expensive and using the 6.5L diesel van transmission computer is alot of work/time.

This is probably a question for Heath Diesel. But can you change the VSS calibration for tire size/gear change without buying an E-prom chip? I really would like the extra 30 hp, but again $325.00 is too much right now. Can one of these E-prom's eliminate the code(s) thrown when using a mechanical wastegate actuator like the Turbo-Master? Is there anything else I can have removed/adjusted with the chip?



I would still really like to know what to do with the gauge cluster. If anyone has modified the interior/engine wiring harness to create a "stand-alone" system for a conversion, please chime in. I am ok with fabricating a sheetmetal dash to fit the cluster, function over form kinda guy.

Best case scenario......

ONE harness for the headlights, turn signals, brake/backup lights, wipers, interior lighting, etc.

ONE Harness for Engine, Starter, Fuel Pump, Gauges/Cluster, Dual Radiator Fans, etc.

Why? A duplicate of the Jeep I am converting now is wanted by a customer of mine. So the two separate harnesses would make copying very easy and versatile. Also if that duplicate vehicle used a 6.2L N/A Diesel or other engine, the separate engine harness makes it even easier.

Cooling- I upgraded the cooling system with SSdiesel's kit so before I tore down the truck it always stayed cool. The Jeep only has 30" Width 19" Tall and a max of 3" Depth for the radiator. Is this enough to keep it cool along with a set of Dual Fans?

Braking- I will not be using the hydroboost from the truck. I will be using a vacuum assisted brake system. Diesel=no vacuum. Is an aftermarket electric vacuum pump sufficient to operate the brakes? Like SSBC's pump?

[cgoffroad]

I am about 70% through this exact same swap. Hope things go better for you than me. Have you done anything suspension related to support the added weight, I drove mine around for a month till a small trail bent my front axle in a 15° V.
A few things i learned. The mechanical pump is the way to go, end of story. dont fight with that harness and ECM

Get a stand alone Glowplug harness, Its easier than trying to split your harness.

Junk your jeep harness and buy a painless 12 or 18 circuit universal harness. you can run everything on the engine and jeep on this harness. and painless will modify a harness to your exact specs.

Your going to have driveshaft length problems with the newer autos and a transfer case all in a stock wheelbase. I ended up deciding on the 6.2 mated to a GM SM465 manual and a NP205. I dont have the exact length but i can go measure if necessary. I went a little extreme and lengthed my frame and body 15" to bring the jeep to TJ Unlimited wheelbase. I added a second row of seats for my kids.

For guages i ran into a problem on the tach. I called peninsular diesel and ordered a set of marine guages they look nice and work well. My GPS has a speed setting so i dont have a speedo.

I see that your not going to run the Hydro brakes. My first try i ran vaccum boost fed by the 6.2 engine mounted vac pump. it worked but stopping distance was scary. I went with the Hydro brakes. check this link out, http://www.jeepforum.com/forum/f8/how-build-hyrdroboost-brake-system-644948/ its how i set up my hydro system and it works great. I got the hydro booster free from a guy scrapping a P-van but you can find them all over junk yards.


I have several discarded auto transmissions in my garage from this swap. I tried the 4L80E that came from the donor vehicle. I had difficulty getting it to shift properly. I did not drop the money into a standalone controller and that might have solved the problem but i could not fit the Dana 300 behind the 80 without moving the rear axle back. I also tried a T350/400 and D300 combo. It fit and worked but I had problems with the valving.

I will be more than willing to be a sounding board if you have any questions on this swap. For me its been trial and error for the last 3 years to get it from a rotten hand me down 79 CJ7 to a trail worthy family toting stump puller. It is well worth the effort though, nothings greater than hitting the gas in an open top jeep listening to that turbo whistle.

Joe