1984 C-10 Silverado CCC help

[Donnylee]

Hi guys,

I recently bought a 1984 stepside. Has a transplanted rebuilt 69 350. Where I live we have sniffer laws so every original smog piece remains on the truck.
It just passed sniff no problem. But I have kind of a baffling problem that appears to be related to the choke light and signal. That I want to sort out.

There is a 3 wire harness coming out of the firewall. Plug has been cut off. The wires are two light blue, one light yellow. It appears they have tried to run these to a 3 wire sensor that is on the oil pressure side front of the block with three wires coming out from the sensor.

The firewall wires appear to have 12V, a Ground, and I assume the yellow goes to the Computer for feedback. If I hook these up my choke light on the dash simply stays on. When you check the sensor it does not have continuity bewteen the 3 terminals not running...you start it, it does with oil pressure. And then of course it triggers the choke light inside the cab.

I am thinking this sensor is not correct for whatever it suppose to do, and seems bizarre a choke signal would be monitored off oil pressure.

I am hoping someone can help me identify the method of operation of this so I can get it hooked up correctly, or confirm that the sensor is in the right place to begin with, or when it should be open/closed state on the switch....

At this point instead of pulling all of this smog off, I want to make everything correct and work again. And this has me stumped.

Thanks for any guidance here, I believe this was a California emissions truck to begin with. But this sensor and its correct operation is a mystery I am hoping someone can clear up for me.

[pcmcobra]

Check this out.
http://www.autozone.com/servlet/UiBr...3d801156bb.jsp

[Slonaker]

The choke is related to oil pressure on our trucks. The choke on a quadrajet won't come on until the engine has oil pressure. They came that way from the factory, but I can't remember why.

Mine s set up with a tee right behind the distributor. There is a gauge sender for the oil presssure gauge and a pressure switch that is wired in with the choke. As soon as the engine builds up enough pressure when starting, the choke light goes out.

I recall reading somewhere that some model years had one sender behind the distributor and the other near the oil filter. It sounds like yours was one of those.

The truck does not really have a computer. It just has a knock sensor on the side of the block that is hooked to the ESC distributor and a little box under the dash. When the box detects pinging through the knock sensor, it retards the timing. That is it. That is as close to computer controls as it comes.

I know I didn't really answer your question about how to fix it, but this does at least explain why you have a choke light hooked to an oil pressure switch.

Slonaker

[krue]

Welcome to the board from South Mississippi!

[ElGracho]

Look at this...

http://www.gmtrucks.org/component/op...ressure_switch

[Donnylee]

Thanks So much for the help and links.... I think that explains it for me perfectly....I think its clear the choke sensor in my case is bad. Also thanks for welcoming me to the board! You guys have a really nice site to exchange, and hope in the future I can contribute back some help!

Meanwhile, I am enjoying this old truck. Runs good, has headers, intake and all the orginal smog bits as I pointed out..but all else is very original right down to the Rally rims with trim rings.....while part of me would like to modify it a bit, their is a voice in my head telling me to leave it pretty much stock as is. Stock 2W step sides are not common....and this one still looks *****in untouched.

My 700 R4 is shifting to soon, and has some sliding into gear problems....(Not crisp shifts) So I may have to have that gone through....But hey for $2K, zero rust, nice and straight truck with a newer 350 engine I am not crying at all!