Gauge He!!?

[ntx78k5]

This weekend my plan is to find out why my oil pressure gauge goes from 30 at idle to peg when I hit the throttle and find out why my water temp guage wont work at all.

When I check for power at the guages they are fine but I cant figure it out. They are the original gauges for a 78K5 with a 350 and the motor is out of an early 80's truck. Ive changed the thermastate twice and still no change.

Anyone having luck with those cheap guage pods from auto zone or orielly? how hard are they to install? I'm no electrician....

 

[pauly383]

All my experience with the factory gauges , came from trial and error . AFTER I had already replaced the senders and it didn't work .

I have had the resistor on the back , between the posts , actually go bad . They are a different color for each gauge .

I actually changed that and the gauge read right again

3 years later the temp gauge sender went bad though

 

[ntx78k5]

So am I better of just going around the factory stuff and just bying one of those $50 pods volt/temp/oil guages for under the dash?

 

[pauly383]

Depends on what you want .

I am bypassing them in the trail truck , and using the gauge pod gauges ( in dash ) .

I didn't mind getting the factory stuff working on the truck I drive all the time . I actually like the factory stuff . I used several used gauge clusters until I got what I needed to make it work .

Its not hard at all , just some diagrams , a multimeter , some patience , and a good understanding that you will need to replace wiring sometimes in old rides

 

[ntx78k5]

Thanks Man, I appreciate the info, its not a DD its a hunting/trail and mud rig, cant afford to get into rocks yet and this thing takes me all over TX during Hunting season. Really dont want to break anything and screw up a hunting trip.

 

[pauly383]

Theres a good post with pics of aftermarket gauges in the dash http://coloradok5.com/forums/showthread.php?t=144476&highlight=gauges+dash

 

[dyeager535]

How where you checking power, and did you check grounds as well?

Best way to test power to the actual gauges would be to pull them out of the cluster, but leave the cluster housing mounted in the truck, then test the spring clips at the back of the cluster housing for the right voltage and good ground.

Those printed circuit boards tend to get screwed up around the wiring connector, plus loose/poor connections all over, so testing what the pins on the gauge are actually seeing is a very good test.

The '80's clusters use quite a few different + and - wires, so it's very possible for one or two gauges to not work right based on those wires. ('90-91 clusters, at least, used a common + and common - for everything)

 

[ntx78k5]

How where you checking power, and did you check grounds as well?

Best way to test power to the actual gauges would be to pull them out of the cluster, but leave the cluster housing mounted in the truck, then test the spring clips at the back of the cluster housing for the right voltage and good ground.

Those printed circuit boards tend to get screwed up around the wiring connector, plus loose/poor connections all over, so testing what the pins on the gauge are actually seeing is a very good test.

The '80's clusters use quite a few different + and - wires, so it's very possible for one or two gauges to not work right based on those wires. ('90-91 clusters, at least, used a common + and common - for everything)

I was just checking for power, do you have actuall readings needed to verify all is correct?

 

[dyeager535]

Well, the senders all use one wire for the "reading" from whatever sender (oil, water, fuel) but use a + and - wire to power the gauge itself.

I believe the range of all the senders is 0-90 Ohms. Obviously varied based on how much fuel, pressure, or temperature is being measured.

Should have infinite resistance on the sender wire if it's disconnected from the sending unit.

 

[ntx78k5]

Thanks alot real good info