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Hello all. Currently have an Accel intake base that I'm cleaning up and prepping for install in a superram setup, taking everything off and replacing sensors and gaskets while I go. I would like some help identifying things though...
It looks like the top one is just a coolant port. I assume the left is a temp sensor, but I'm not sure what the bottom right is, almost looks like a coolant level sensor.
Is this a vacuum port? I'm also curious what the screw is behind it.
This is the port for the EGR pipe in the rear. I'm removing smog equipment, but I'm still curious about that screw right next to it.
First photo, those are both coolant temp sensors. The one on the left feeds the ECM wiring harness with temp information, and the one with the blade setup is like the one used for the coolant temp gauge in the dash display for some years - often also seen in the head near spark plug holes.
Second photo, the pipe is for the PCV hose to attach from the valve cover. I don't know about the screw behind it.
Third photo, that plug is covering the hole which often has a coolant steam vent pipe fitting plumbed into it, which then tees into the heater hose nearby the AC blower enclosure on some years.
Thanks, that helps. I pulled the original from storage to compare, seems one of the original temp sensors is a different style. This is from an 88' for reference.
Something else that I noticed while researching the intake. I noticed that the rear coolant ports are restricted on the old gasket, and apparently that was something unique to the vettes. I read around some posts saying that it's okay to use a normal intake gasket without the restrictors so long as I cap that coolant steam vent pipe. My engine isn't stock anymore so I imagine it'll make a bit more heat. Will this be an issue in the long run? I didn't even know about the block off plate when I bought the intake gaskets...
Thanks, that helps. I pulled the original from storage to compare, seems one of the original temp sensors is a different style. This is from an 88' for reference.
If I were you, I'd take those sensors from the original and move them over to the newer manifold in same positions for compatibility with your wiring harness. If you get new sensors, look up the GM part for your year to get the right connector types on the new ones.
This photo is how the sensors should be set up on 86 - 88 . The top is a water hose, bottom left is a Thermo Time Switch which senses temperature of the engine, and if necessary, pulses your 9th (Cold Start) Injector for 8 seconds to assist in starting. The Thermo is rare, being discontinued years ago, so if you have one, its valuable. In 89 they reprogrammed the ECU such that the whole cold start thing became redundant. You will see that the connector to it is identical to one of your other 8 injector connectors. On one of the 2 electrical injector harness's (left or right) you will have an extra plug for it. The bottom right is the ECM Coolant Sensor . Two pin oval plug, yellow & black wires.
Now, I believe there are a further 2 sensors - Located between cylinders 6 & 8 and 1 & 3 on the heads. The single blade sensor in your original photo is a typical Engine Temp Sensor but does not go at the front of the engine, but at the side. The 2 additional sensors are (1) Engine Temp Sensor and (2) Cooling Fan Switch.
I am still trying to figure out which goes into which side of the heads, so can't help you on that. Hope this belated reply helps.
Since everything else is done, I'm doing the block sensors and the fittings. The coolant fitting on the front... Is there any reason for an o-ring inside of it? Took it off the original to put on the aftermarket, and I saw it sitting in the middle of it, and I can't fathom what it would be sealing in there.
Intake Port/Sensor identification
