TBI engine in a 85 C-10

[salrod00]

Here we go again with this thread. I have been checking on the web and quiet cant find the answers i have looking for. i have a 85 c-10 and im going to put a 89 suburban motor in the pick up. its my first time doing this so any advice will surely be put to use. my concerns are the fuel ratio and the wiring situation. any pics would also help but for most the advice will help thanks in advance and hopefully i will get this done in a day or two.. thanks

[rfmaster]

Salrod00

Since you have a donor it is relatively straight forward.

Engine - get all sensors, relays and harness transfered from '89 into 85. Take lots of pictures during removal. Label all connectors. IIRC 85 used CCC and ECM. TBI harness has additional circuits so retaining CCC harness & re-pinning ECM connector is asking for headaches for the first go around. Your '89 has 1227747 ECM which is well known and has been hacked extensively. Make sure that you get VSS sensor - ECM needs to know speed fuel control. I assume that both trucks are equipped with 700R4.

Fuel system. TBI fuel system uses three lines. 3/8" for supply, 5/16" for fuel return and 1/4" for fuel vapor - charcoal canister. Take a look see what '85 has. IIRC in '85 mechanical fuel pump was still used with CCC. Supply line is porbably is 3/8", but I do not know if you have fuel return line! You may need to fabricate . Just solid line - do not use rubber for long runs.

Gas tank and fuel pump. Suburban with TBI used in tank fuel pump and a baffled tanks, whereas 85 used old style saddle tanks. You can still get 87 tanks to replace the non baffled tanks. You'll also need a new pickup, fuel pump, etc.

//RF

[Russell]

If you need help with wiring / hookup, PM me, I've done this swap twice now

[salrod00]

ok what i did on the tbi was take the computer out and bring the harness out from inside the cab out to the engine bay. i didnt disconnect nothing of the main harness of the motor. theres another harness that comes off the fuse box and it also just got disconnected. so now i got two big harnesses that will go with the motor. as for the fuel lines i see that it gots two coming from the block. they are both steel braided one is for supply and the other is the return.is there a way where i can you the same tank of the blazer or so i put a electric pump outside the pickup ol gas tank. would the drive shafts match up or would i have to get it shortend

[gchemist]

Here is a guy putting one in a 77 truck from an 89 Suburban.

[Russell]

Sounds like you did good in unhooking everything! You'll probably want to snag the wiring that went off to the driver's side of the dash through the small connector by the ECM. In specific you are going for the ALDL connector and the park neutral switch wiring. The rest will be power and ground wires along with the speed sensor wire, service engine soon light, and an ignition wire which you can run yourself.

You won't need to use the thick harness that went off to the driver's side of the truck and into the fuse block. You'll be able to use your old original 85 wiring harness to make it a far easier swap. When I did my swaps the only wire that I found that was common to both harnesses was the AC wire. Just clip off the wire that runs into the engine harness and tie the one from the fuel injection harness into your stock AC wiring if so equipped.

If your truck has emissions equipment you may need to do some separating there as some of the power may be supplied by the engine harness.

Yes, you can infact install a Blazer or Suburban fuel tank into your truck. Mounting the tank is easy, but you'll find setting up a filler neck to be a major pain in the backside. You'd be best to install an EFI fuel tank or two from an 87 regular cab truck or 87 - 91 crewcab truck. You can use the fuel pump that is currently installed in the Suburban's tank in the pickup's sending unit, but you cannot interchange the sending units themselves.

If you wanted a frame mounted pump, get one that is rated for 15 - 20 PSI and make sure that you use proper fuel injection fittings to ensure you don't have any leaks. Frame mounted pumps are convenient but tend to be a fair bit noisier and don't typically last as long an an in-tank counterpart.

As far as driveshafts go, it depends more on what transmission you are planning on using (original or donor's). What transmission do both trucks have right now?

[salrod00]

Ok here is what i got done today. i took out the old 305 out of the pick up. i got everything ready to transfer the 350 into the pickup. im going to use the suburban from clip on the pickup.the condenser,radiator and evap canister are also going with it. now for the motor im putting new gear box,motor mounts,transmission mount, oil pan gasket,and rear seal just to be on the safe side. i noticed that on the side of the tranny where the speed cable go it is leaking tranny fluid. is that L looking shape that holds the speed cable to the tranny hard to switch out or not. also when yall say crew cab gas tanks is that the ones that have the fuel pump that i need.

[salrod00]

Russell thanks for the help as well as everyone else. but Russell when you say ALDL connector and park neutral switch wiring what color are they. where are they at again and are they all together or is it better to take the whole wiring inside the cab out.. thanks

[rfmaster]

salrod00

ALDL connector is usually a black connector - dual row (12 pin).

Park neutral line is orange/black - pin B10 on ECM conenctor.

//RF