Fuse block

[Dogman12]

Are the fuse boxes from an 85 the same through 89? My truck came with the electric carb with esc. The block has two ports labeled ecm. I have an 89 tbi engine and harness that i am going to be installing and am stuck at the wire going into the fuse block. Any help on this would be great, i have searched and found alot on what the ecm needs but not alot on the fuse block side.

Thanks
Jesse

 

[dyeager535]

So you are stuck at the firewall connector, or powering the TBI ECM from the fuse panel leads?

 

[Dogman12]

Powering the ecm does not seem that hard, I have the whole harness for the tbi engine and not sure if it would be easier to swap to an 89 fuse block or start splicing the wires at the 85 fuse block. I hope this is not to confusing.

Jesse

 

[dyeager535]

Unfortunately it is, since the CCC setup is understood so little, at least in these trucks.

The same setup was used in cars, you MIGHT be able to find something out about conversion to EFI in say, carbed Chevy cars of the 80's, but other than that, factory manuals are about the only way to figure out how to do the wiring.

Since you have both, it might be best to start comparing them. You probably won't need to do any splicing, as a matter of fact I'd recommend against it unless it's the ONLY solution. Most everything is probably there (just wrong connector pinout) but you can remove the pins from the connectors and swap them around if the connectors are the same.

IIRC, everything unplugs from the fuse panels (power doors, heater, interior lights, etc) so while it would take some time, the swap should be fairly simple if you decide to do the whole harness.

Only thing I can think of the top of my head that would be missing are two leads for the TBI injectors...the CCC setups only had one solenoid, and I have no idea how that was powered. Probably similar, ECM grounds an ignition switched 12V, but I wouldn't assume anything.

 

[Mike D]

Buy a stand alone TBI harness from Howell Engineering. They have their own fuses and you only need to connect three wires ( 12V +, ground -, and ignition + ). I have been there and done that! Buy the harness - save the nightmare.

 

[kennyw]

Powering the ecm does not seem that hard, I have the whole harness for the tbi engine and not sure if it would be easier to swap to an 89 fuse block or start splicing the wires at the 85 fuse block. I hope this is not to confusing.

Jesse

Since you have the complete harness, it would be a couple hours work to swap the whole thing out, fuse block and all. Most of the little stuff like headlight, steering column, wiper connections will all be the same anyway.

 

[Dogman12]

Thanks for the replies, The two blocks look very close the same as but the connectors look like they have changed a bit. I have two books with diagrams, they both have little about the engine side of the fuse box. My truck has no options but ac so it is not crowded. The esc and electric carb stuff is still all over the place. I will look into Howell and see waht the price is like.

Thanks

 

[dyeager535]

$3-350 it looked like yesterday. I wouldn't if I had both harnesses, but I like doing electrical stuff.

I'm really interested to see what you find out, the harnesses could be very similar. If you don't have a year specific wiring diagram, it's going to be tough. Haynes are too generic year-wise.

 

[Dogman12]

I have compared both harnesses and where they go to the firewall the wires are very close, the plugs look a little different. I have not pulled the harness off the truck yet to see how close they are. The basics to make it run are the same. Here is a site i found that has great wiring diagrams, when you go to the site they are at the top right says wiring. the site is brochures.slosh.com

I will post up when if start the wiring, lots of cleaning etc. to do first.