Tbi to carb choke 12v

[chappys4life]

Just finished swapping my 90 Jimmy from tbi to carb. Right now I have the 12v taken from the tbi to the distributor and then the tach going to the fuel relay.

Now I’m trying to find a good spot to wire up the choke on the carb. I was wondering if any of the old sensor plugs could be a good 12v on key, or somewhere that makes sense to snag.

 

[HankScorpio]

Why did you attach the Tach signal to the fuel relay?
Any 12v switched should work for the choke, you could probably piggyback to the wire going to the distributor.
Did you swap an older style HEI distributor in?
You are probably going to have some trouble with the fuel relay, there is some interface with the oil pressure sensor on some of the tbi systems. You might need to rewire the relay to a switched power source that has nothing to do with the old computer wiring. Your fuel pressure is going to be way too high with a stock 1990 pump.
Carb? Gross. To each his own I guess.

 

[chappys4life]

Why did you attach the Tach signal to the fuel relay?
Any 12v switched should work for the choke, you could probably piggyback to the wire going to the distributor.
Did you swap an older style HEI distributor in?
You are probably going to have some trouble with the fuel relay, there is some interface with the oil pressure sensor on some of the tbi systems. You might need to rewire the relay to a switched power source that has nothing to do with the old computer wiring. Your fuel pressure is going to be way too high with a stock 1990 pump.
Carb? Gross. To each his own I guess.

When I looked up on YouTube using the distributor tach was the most popular way to trigger the fuel relay. I have debated just using a switched wire to trigger the relay as it does look for oil pressure first which is nice in a way. Why I am looking for 12v switched for the choke but maybe the relay too.

I used a fuel pressure regulator that is return style to make sure it was at the right psi. Just used the m6 to an6 conversion.

Not gross at all. Got tired of the bs tbi not being able to be repaired, no one works on it, and the scanners are so old they are hard to get. I tried to make it work, then went to 3 mechanics. It’s just not a good system for modern times.

Carb works great! I thought about a terminator but a lot of work and cost and not sure I really care that much.

 

[HankScorpio]

I have to start in the cold and deal with altitude changes so the carb is a no go for me. I really like how my TBI trucks run.
The tach signal seems like a poor choice to run a relay. Its not a clean 12v constant. I am not sure why guys would use that when there are switched 12v sources right there under the hood.

 

[HankScorpio]

I think its a pink and a white on the TBI distributor. If its the pink you are hooked to 12v switched. The white is the ground side of the coil and that's the tach signal.

 

[chappys4life]

I think it’s a pink and a white on the TBI distributor. If it’s the pink you are hooked to 12v switched. The white is the ground side of the coil and that's the tach signal.

Ok thanks. I will hunt for it. I was reading there is a pink w/ black stripe for the egr that I will hunt for too.

 

[Blue85]

It's been a long time, but I seem to remember the choke was wired to something hot only when the engine is running. If it's just switched ignition, and you have any trouble getting it started, premature choke opening can make it worse.

 

[chappys4life]

It's been a long time, but I seem to remember the choke was wired to something hot only when the engine is running. If it's just switched ignition, and you have any trouble getting it started, premature choke opening can make it worse.

Good to know I will keep and eye out. I know typically I just use 12v keyed on my older cars but maybe this one is a little different.

I found 3 pink with black stripe in the old harness (have them laying on the intake for now, need to cleanup) and 1 of them was 12v keyed. Hooked it up and worked great. Need to adjust the choke a little but seems good so far. Thanks for the help.