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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: Joe-NC on April 06, 2011, 07:36:06 am

Title: Wacky Gauges
Post by: Joe-NC on April 06, 2011, 07:36:06 am

I have an '84 truck with a 305 that someone took from a car (about '86, 1-piece rear main seal). When I got it, the temp and pressure gauges were unresponsive. Just installed a new temp sensor and oil pressure sensor.

When I first start it, the oil pressure is off the gauge (over 60) until it warms up. After warming, it reads about 50 while idling. The temp gauge reads 210 as soon as I crank it, which of course is wrong. Then it shows almost in the red (260 degrees) while idling. I shot a heat gun on different places in the engine while idling warm on a 70 degree day. Everything reads about 150. Radiator and hoses, top and bottom, both read around 180.

When I rev the engine, the oil pressure goes up slightly and the temp goes down slightly almost in perfect sync with the gas pedal. Is this normal?

Is it possible these gauges are not compatible with these sensors? 

Title: Re: Wacky Gauges
Post by: Irish_Alley on April 06, 2011, 10:04:00 am

Are they stock gauges

Title: Re: Wacky Gauges
Post by: Joe-NC on April 06, 2011, 02:13:05 pm

Yes, they are stock for the '84 truck.

Title: Re: Wacky Gauges
Post by: Captkaos on April 13, 2011, 10:08:29 pm

You may have the wrong sensors, or the gauges may be bad.

Title: Re: Wacky Gauges
Post by: Cheyenne on April 13, 2011, 10:48:25 pm

 agree with what the guy before me said, also when people go switching around motors that is diffrent sometimes it cause trouble. I to had a motor in a truck same trouble as you talked about.. I did get the oil pressure sensor to work after a bit.. You got harness from the truck not hooked up etc when somebody puts something in there you never know what they did.. You have to follow everything from the sensor to the cluster you get it. Most likely was done wrong or didn't care you get it with patience..