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1 Pin Engine coolant Temp sensor nowhere to be found

Discussion in 'General Chevy & GM Tech Questions' started by Ethan, Oct 27, 2010.

  1. Ethan

    Ethan Rockstar 100 Posts

    So, I have a 1994 Chevy Silverado 1500 2wd with a 350 cu in TBI with a bad coolent temp sensor. The old one kept reading 160, so my gas mileage sucked. For the life of me I can not find a replacement one that is an exact replacement. They keep giving me these 2 pin coolant temp sensors. Well, the one on my truck is a 1 pin design, but has the weather proof connector. No where that I look can I find the right part.

    So, I buy one of these two pin sensors, yank one pin and file down the weather proof connector so it would fit in there, and nothing. Idk if anyone has ever run into this problem before, but I'm extremely frustrated.

    My question is, I have a new 2 pin coolant sensor, I need to go and get a connector for it, but when I do, can I just run the original wire into it, and then run the second wire to ground, cause I imagine that's what the second pin is for, ground. I would like to know beforehand before I go and buy a $14 connector, the outrageous prices for these connectors is going to bankrupt me.

    Any help is much appreciated.
  2. stephan

    stephan Rockstar 3 Years 5000 Posts

    Are you talking about the temp sensor for your guage or temp sensor for your fuel injection? You may be looking @/working on the wrong one & that is why what they are selling you doesn't match your wireing.
  3. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    Not trying to sound rude here but for reference on the 350TBI the "coolant temp sensor" is mounted up by the thermostat housing with a dual wire connector(which is for the PCM to read the engine temp to allow the right fuel mixture), and the "temp switch" is mounted between the number 1&3cyl on the drivers side head with a single wire (this runs your guage cluster)
    Also how poor is your milage, i have owned several of these trucks (2 1994s and a bunch of other years from 1988-1994) i never got more than 15mpg on the highway with them on a regular basis sometimes the stars would align and id get 17, as to the city milage i dunno cuz it sucked that bad i didnt even want to look. But if your milage is bad and your coolant is truly at 160degrees then you will want to look at the Thermostat and replace it with a factory 195 unit to get everything right, and possibly consider a tuneup since the cap and rotor even on the TBI motors werent the best and lasted me usually a year or two before needing replaced.
  4. Ethan

    Ethan Rockstar 100 Posts

    Ok, so I'm jacking with the one on the side of the block, and since it's not hooked up anymore my temp gauge reads 0. Before all this mess happened, I was getting about 20 mpg on the highway and 17-18 in the city on a good day. I've already replaced the thermostat, flushed it multiple times. The coolant shows 195 like it should with a external temp gauge, the temp gauge always reads 160 when I know the actual temp is at 195. So right now with it unplugged, I get a crazy amount of horsepower, but my gas mileage is crap. So what I'm looking for is a temp switch?

    This truck is in excellent condition, 160,000 miles, I wash the motor with degreaser every time wash the truck, I replaced things before they go out, etc. Never had any major engine problems.
  5. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    Yes..............
  6. Crawdaddy

    Crawdaddy Epic Member Staff Member 5+ Years 1000 Posts Platinum Contributor

    I had the reverse issue. I needed the single-pin one for the coolant temp gauge on the side of the block, but they gave me the 2 pin one for the intake. I was able to source the sensor from autozone once I realized the mistake.

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