Howell TBI help... please

[elks]

So I just finished installing a used Howell TBI system into my blazer. I have got it up and running but since it was used I did not have all the neat little tabs. My problem is I can not figure out the darn check engine light wires. I have all wires accounted for except 1. I have one black wire that leaves the loom with the wire that goes to the fuel pump. I a, not sure if it is just a ground or if it is for the CEL.

When I set up an affordable fuel injection kit the cel required 12 volts in and the com grounded it to light up. Does this system do the same?

Anyone know? Mine is the to i system for converting a carb to thi.

 

[63chevyll]

Funny this come up. I called Howell today about my TBI harness and an issue i was having (not a howell problem)

Ill take a pic of what i have so you can compare.

 

[elks]

Thanks. I just wish I could get a full wire diagram for the unit with wire colors etc. The direction have no pictures and in some cases are written pretty weird.

I just need to know if the wire that exits with the fuel pump power is a ground, or ???

 

[63chevyll]

And these

 

[63chevyll]

I would have to trace my wires better but this is what i have for now

 

[dremu]

My Howell harness is (almost entirely?) wired with GM colors, so you should be able to use factory wiring diagrams to see what's what. Mine has two wire for the CEL, pink and brown. Like your Affordable system, the hot side is hot all the time and the minus side is switched, if memory serves.

However, as pointed out, the surefire way is to trace your particular harness.

IH8MUD has a whole ton of info on TBI conversions, oddly, including lots of wiring harness info

http://www.ih8mud.com/tech/tbi350.php

specifically

http://www.ih8mud.com/tech/ecmpin1227747/747ecm1.jpg

You can then beep with an ohmmeter to figure out which wire is the CEL (pin A5, should be.)

-- A