Diesel swap: ECU concerns

I don't have any dash lights. That's why I said I wasn't sure about 2nd gen but it's not that hard. You're in over your head if something like unplugging an ecu is tripping you up. It's not an easy bolt on project.

 

I understand its not easy or bolt on. I just wanted to double check that the ecu wouldnt cause problems of any sort

 

OK, so a few months has passed since my last post on this thread and I still want to do a diesel swap. I understand why people say to just buy a diesel truck. Yes, it'd be easy, but a diesel conversion is something I've always wanted to do. I have two coworkers/friends who know a lot about mechanics and diesels (one is currently taking classes at a diesel mechanic school and works one diesels 5 days a week and the other is constantly dicking with his diesel truck. I am capable of TIG welding (I know how but i still need to buy a TIG welder off my uncle) and understand basic to slightly more than basic mechanics. What I need, however, Is some advice and info from those tech nerds on this site. Here's what I'm currently working with (nothing purchased or cut off my truck as of now so i can still go anywhere with the swap):

Engines I'm considering in order of desire: 24 valve 5.9L 6BT, 12 valve 6BT, 3.9L 4BT (all cummins)

Transmissions: NV4500 (5 speed manual) or the NV5600 ( 6 speed manual). Preferably the 6-speed

Transfer case (if i can get my hands on a 4wd tranny of the above two options): Not sure yet. Still looking into that. Don't know what will fit inside the trannies (stop laughing)

ECU: The 4bt and 12 valve are mechanical so no ECU needed there to run them, as far as I know. The 24 valve does require an ECU, however, it's a stand alone unit that can easily and cleanly be removed from a donor vehicle with the engine and simply rewired in my truck. A simple hookup, from what I understand and have read.

Differential: Probably gonna pluck the diff. off the donor. Don't want to trust too much on my drive train to support diesel torque, even though I don't plan on goig WOT all the time. I'm fairly moderate driver, but still want the extra tow power and mileage. Still open to ideas and options for the diff. Making a dodge diesel diff. work on my truck would require a lot of fabrication. There's probably a better option for this section.

Suspension and axles to support weight: not worried about axles to support the 4BT since the weight is only APX 400Lbs more than my 1GR-FE. Suspension for all 3 engine would still have to be upgraded. I am open to options, but I was thinking about getting Bilsteins, front and back with an add-a-leaf along with stronger uca's. For the 12v and 24v engines, I need advice on whether or not the axles can withstand that weight (around 1,000-1,100 lbs for both engines) and towing. If I need stronger axles, where can i get some?

Fitment and supporting: 4Bt with the suspension I am not worried about at all. I've seen people run 4BT's in 1st gen tacos, 2nd gen tacos, and even a mustang (no shit, google "mustang with cummins"). Somebody put a 6bt (both 12v and 24v have closely similar dimensions) in a first gen, which are slightly smaller trucks, If he managed that, surely I can squeeze a 6bt in my second gen PreRunner. I can fabricate some very strong motor mounts. Pretty sure the frame can handle it, but if anyone objects to that, please speak up. Like I said, I made this thread for advice for myself and those reading it who may have the same idea of wanting to do a cummins swap.

Fuel pump: I'm thinking my current pump is fine, but I could be wrong on that. If so, any pump suggestions?

Drive shaft: probably should pull the shaft off the donor vehicle and have a shop cut and balance it for me. Not sure what the capabilities of mine are

Radiator: I know the cummins will need a bigger and better radiator to keep the diesel engine from overheating. I'm sure three guys in a shop are more than capable of replacing a radiator and maming it fit.

Brakes: more weight means better braking required. I've been meaning to upgrade my brakes, this will be the perfect time while the truck is being upgraded in so many ways. might try and pull the master cylinder off a tundra.

MPG goals: As long as my city and highway mileage don't decrease, I'm fine with that. I am expecting slightly better mileage from a diesel in a midsize truck, but not exactly expecting Prius numbers.

So far that's what I've come up with. Modifications will take place when the truck is paid off in no more than a year, plenty of time to gather more info. Please, no comments saying "This is retarded. Buy a diesel" or anything like it. I've already made my decision and think this would be a great swap and a bad ass project that not enough people document in detail, especially with Tacoma's. When doing the conversion, I will post videos on youtube and document the process on TW. Let The comments flow

 

Now that I look back on this thread, @RAT PRODUCTS has a 6bt in this 1st gen. Perfect example of my fitment theory. Looks like a tight squeeze but it runs

 

If it were me, I'd pick a 4BTA with an inline injection pump mated to an NV4500 and its associated HD transfer case. The mechanical pump Cummins have lift pumps on the side of the engine. It'll fit easier and make more than enough torque if the pump is tuned and you put in larger injectors and turn up the boost. 24V Cummins are known to have injection pump problems. The 24V pumps are lubricated by the fuel and when you loose fuel pressure, the pump shits the bed = big dollars. Mechanical injection pump Cummins are much more robust and not lubed by the fuel. Rear ends could be narrowed Dana 70s - same rears in a 3/4 ton Dodge Cummins. I think Dana 80s are probably overkill. Driveshafts & associated stuff are the least of the issues to deal with. If you want to stuff a 6BTA in it, don't resort to cutting the firewall. It'll look like a hack job. A friend in the diesel truck club that I used to be active in stuffed a 6BTA in a round nose Dakota. It fit but needed the radiator to be squeezed in with pusher fans along with a body lift.

 

You, sir, are extremely helpful. And about what you said about fitment, I agree with the 4BTA. I took a look and some rough measurements using a foot-long piece of clear vynil tubing i had and now i seriously have no idea how @RAT PRODUCTS or the other guy with a 6bt in a first gen made it fit in that truck. May cut the firewall but i dont know for sure. I am not willing to do the same. So, 4bt it is. Big power, small package....wait a momemt..... forget i said that. But yeah. 4bt. Good point there. I have two more questions. How to i convert my gas pedal to use a cable so i can use the engine? Tried looking this up but got no helpful results. Also, would my current radiator be fine or will i need a bigger one? I know its alot of questions, but i want to get this right to avoid costly and destructive mistakes.

 

Your not going to convert your gas pedal. Get one from a junk yard that has a cable already - I'd look at Dodge Cummins first. For the radiator, it'll depend on how the outlets line up. Radiators in the Dodge Cummins are sized to be able to pull max towing out of Death Valley in the summer. I used to run mine all winter without the mechanical fan so that is get heat. Even after converting to electrics, they wouldn't come on that much in the summer when running empty. What's in the truck may be enough but you can only tell after its together and trial run it.

 

Alright. I am currently talking to a guy about getting dana 60's for the front and rear axels. As soon as this truck is paid off within the next 10 months or less, ill be doing some junkyard hunting for a 4BTA, nv4500 or nv5600 (whichever is available), gas pedal, and maybe suspension. Not sure yet if some susoension made for the tacoma would do the job at the front end of holding that 800-900 lb engine