Im new to tpi systems and this is probably a dumb question, but I can't figure it out. There are two sensors on the front of the intake one is the cst and the other i have no idea. Is it for the temp switch for the electric fans? It's the one on the right, it has two flat prongs inside the plug. Also There is a hole similar to the egr valve hole on the back right of the intake. I've asked about it before and never got a straight answer. The motor is an 86 L98. Thanks for the help! Jimmy

 

Back right? As in passenger side or what?

As for the sensor, thats probably the cold start switch. If it looks like an injector connector, thats what it is.

 

Yes on the pass. side rear. It is angled exactly like the runner ports, right next to the dist. There is also a 3/8 hard line, about four inches long directly beside it. Can you tell me what it is for? The plug is like an injector plug. Since I converted my harness to SD I can just plug that sensor hole correct? Thanks again

 

The sensor on the front of the intake next to the CTS is not a sensor, it is the cold start switch. It controles the ninth injector during start up. GM did this from 86 to 88 and then rewrote the code in 89 for the ECM so that the ECM would add the extra fuel at start up and did away with the ninth injector.

 

Sounds like you have a corvette intake base. That would be where the EGR tube hooks up to the exhaust manifold. Theres no heat riser/EGR passage in the vette heads so thats what they did to get exhaust gas into the manifold.

 

Yeah it is a corvette motor, forget to clarify. I had the egr codes removed from the cpu also so I guess I'll close it off also. How about that hard line right beside it? thanks for the help

 

Does the hardline head down to the exhuast headers/manifold? That would be the EGR crossover.

 

The hard line right beside it is a coolant line used in TPI Corvettes. It would normally hook up over near the heater box to the heater core coolant line. It is there to promote coolant circulation in the back of the manifold to help cool things down back there so that the aluminum cylinder heads would have less chance of warping. It also helped burp any air out of the intake manifold that may of found its way back there somehow. I have pictures of it somewhere and how its hooked up in my vette, I'll look for them. You can probably just unscrew the hard line and fitting and put a plug in it.

 

Here we go, hopefully this helps.









I have my EGR blocked off with a corvette EGR tube gasket and a small steel plate over it.