Ok, I am trying o figure out how a speedo gauge works on my 1990 K5 blazer 350 with 700r4 tranny. It has the electronic type sensor off the t-case.
Reason I ask is can I use the speedo with out the ecm computer? OR does the speedo have a stand alone computer that can operate seperate from the engine ecm.
My goal is to swap a 6.5 diesel into the K5 I have all the stuff and 2 doner trucks also.
Thanks for the help, Forrest

 

OK, it's been a while, I have completily gutted two running trucks, a 1982 gmc c10 6.2 diesel and a 1984 gmc k20 6.2 diesel.
I have just started the conversion last week to install a 6.2 turbo diesel into my 1990 K5 blazer that had a 350 TBI engine.
Running into LOTS of problems, first of all my 700r4 tranny was weak, so I pulled the gas engine, tranny and t-case and sold them. I installed the turbo 400 and 208 from my 3/4 ton pickup cause it was allready set up for diesel. The drive lines are a perfect mountup, but the crossmember holes are off so I have to redrill them.
Next is Im using the factory tbi in tank fuel pump, this is debatable, but Im going to try it. Trying to find the right wire to power the fuel pump was a challange, I have removed the factory wiring harness, ecm, DRAC box, exhaust, gas filter, radiator and vacuum booster.
I installed another battery tray, cut the high pressure fittings on the fuel lines to accept normal hose, installed a hydroboost unit, now things get interesting. In 87 or so gm went to plastic master cylinder resevoir. Well the part that fits into the hydro boost is too large to fit in the hole. So I got a master cylinder for 1986 K30 1 ton with a diesel to give instant pedal response. I got the engine all ready to go in with the ATS turbo, hopfully I will have er in by wendsday, I will keep you guys posted on the progress.

 

Today I got the engine installed, well kinda....I found that gm changed the bolt pattern that holds the motor mounts to the frame, my 1984 mounts wont fit!!!!!!!!!!!!! SO, I ordered mounts for a 1990 K5 with a 6.2 diesel. SO MUCH FOR INTERCHANGE between gm trucks......Got the wiring harness mess kinda delt with, HAAA, what a pain. I now found that my oil cooler lines also wont fit cause the K5 has an added reinforcement ridge on the firewall that wont allow the oilcooler lines to work. Also the crossover pipe for my exhaust wont work cause the front drive line is in the way.........HOLY CRAP, I will never try this swap again

 

sounds like a very interesting build, i will definitely follow this one. i dont think gas to diesel is ever easy tho lol

 

I am beginning to find that the best diesel swap for a blazer is to find a K5 newer than a 1981 and older than a 1986. These years both the trucks and blazers had common parts, once you get newer than 1987 you run into fuel injection wiring, different mounts, all kinds of stuff.
Diesel doner trucks are more readily available in the 1982 to 1986 range also. Older blazers will work too but the wiring harness plugs are different than 80's diesel rigs.
OVERALL best canidate for a diesel swap. 1983 to 1986 K5 with a 305 or 350 with 700R4. all youn have to do is change the torque converter, and add hydro boost system, with a big diesel radiator. Most doner 1/2 ton trucks with 6.2's allready had 700R4 trannys in them, and most of the trannys are junk.... Get the tranny updated to a post 1987 with a shift kit and it will last just fine.
Any one got any questions, feel free to ask, this is my fourth gas to diesel conv.
#1 1984 c30 dually 454, swapped out to 6.2 diesel
#2 1982 volkswagon rabbit gas converted to diesel
#3 1984 dodge W-350 360 gas, converted to 5.9 cummins
#4 1990 K5 blazer 350, to 6.2 in progress