On the older TPI apps ($32) there is 4 coolant sensors. 1 head goes to gauge, one head goes to fan switch, front of intake has two. One goes to ecm (which one?), the other goes to ???

I'm gonna repin my vette to a '730, and replace one of the front coolant sensors with the later style sensor and plug, but need to know which sensor is for the ECM, and wtf the other one goes to. None of my fbody or ybody manuals have 2 sensors listed in the intake, but i've seen NUMEROUS older TPI setups with two.

-- Joe

 

1 should be for the cold start injector control.

The ECU one should be the same for both old and new ECUs, but I'm not sure on that.

 

The plugs are different. The newer style coolant sensors use the same sensor and plug as the manifold air temp sensor. Both of these use weird *** wacky plugs. I'm just having trouble finding a helms/GM ecm schematic. My GM service manual is from '91, and my other manuals are haynes and just shows the circuit output, not wire colors.

Thanks!

-- Joe

 

OK, so you have the two cylinder head ones down. One is a fan (passenger side?), and the other is temp gauge (drivers side). I can't recall the connector type for the fan, but the gauge is a blade type with insulator body.

so the two in the front, one is ecm, should have a 2 pin weatherpack connector, with a yellow and I think black wire.

the other is the cold start, and that part has a brown or reddish body color, and the connector is very much like an injector plug, square-ish, with a metal wire release lever.

that should be all of them.

 

Yellow and Black, is the sensor for the ecm.

 

Rock on.

My only complaint thus far about the miniram is that it doesnt have enough vac ports, and I really don't feel like drilling/taping another. Maybe I can run the map + fuel reg on the same port, then t off another port for everthing else. that will reserve the left side so the pvc and brake booster can have their own ports.

The vette has a crap load of vac lines. another complaint, they don't run the purge control on the canister like a fbody. They run a purge control vac device bolted to the thermostat housing. I don't understand. What i'll do is lengthen the wires, and run a fbody charcoal canister.

-- Joe

 

I wouldn't recommend T'ing the MAP or Regulator to anything. They should both have a direct connection to the manifold. Maybe if it was a big ole fat fitting that had 2 smaller ports it could work ok.

 

It would be like a 8mm barb, t'd to two hard lines.

-- Joe