name this part,tbi 350
 

I have chevy tbi in 72, donor harness is 1991 chevy 1500 . engine is 1990 suburban,
I have a couple of pieces on the harness that im not sure of , if u know please tell me what they are and what they do please.

one is the plug with 2 gray wires going in to it that is jumped with a fuse .this plug with the fuse if u pull it truck stops running. i believe its some how attached to the fuel pump relay.

the other is this gray box has a circuit board in it,

the other is the fuel pump relay green/ white wire. only starts if i have 12 volts to gr/ white wire. it is partly bare to attach 12v to , is this all right cant find any were to attach 12 to get it to work any ideas.

Re: name this part,tbi 350
 

The item in the first photo is simply a fuse holder and most likely powers the fuel pump relay if that is where on of the grey wires is going. The other wire should be connected to battery voltage or ignition voltage somewhere.

The grey box with the circut board does not look factory. Is that all purple wires coming out of it? Where do they go? This looks like it might be some type of alarm gizmo but not sure.

Stay tuned for more information

Re: name this part,tbi 350
 

Firts pic with the fuse should be your fuse for the ECM. Not sure about the second pic maybe with the Vehicle speed sensor? Third pic is your fuel pump relay. I also installed a TBI system on my 72 Blazer. I used a custom harness it got rid of the junk you don't need. Good luck I'll help where I can:metal:

Re: name this part,tbi 350
 

Ok rereading your post looks like someone wired a fuse in line with the relay for the fuel pump.

Re: name this part,tbi 350
 

no this is stock harness was just thinking had some thing to do with fuel , may be not . I think your right it being fuse holder. bought that way with the fuse in it . what is weird is if u take fuse out and test one side has power that goes to computer and other reads ground bl/wh on the computer. plug in fuse and runs great,

Re: name this part,tbi 350
 

Try posting in the right message board. You'll find members more familiar with the workings of TBI if that's what they drive. I can't go out and look at my '72 to compare.

Re: name this part,tbi 350
 

thanks for your help, special k

Re: name this part,tbi 350
 

if you can give me the service number on you ecm i can get you a pinout sheet with what wires go where.

Re: name this part,tbi 350
 

here u go i hope this is it

Re: name this part,tbi 350
 

thanks for your help

Re: name this part,tbi 350
 

here you go :metal:

Re: name this part,tbi 350
 

i have some more that are a little more detailed if you need them but i'll have to email them as they are to big to post

Re: name this part,tbi 350
 

:chevy: :5150: :uhmk:

Re: name this part,tbi 350
 

1227747 is the ecm service no. the asdu letters on the right side is the service no. for the computer chip in the ecu.