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Good info here, I need to do some trouble shooting on mine!
CK5
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Baseline new (to me) Jimmy
- Thread starter green55
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At the back of the truck, driver's side, inside the frame rails just forward of the fuel tank will be a two wire weather pack connector. With the key on, (engine doesn't need to be running) disconnect it. Gauge should slowly move to over full. Easy first step in diagnosing gauge weirdness.
My suspicion with your temp gauge is that either the sender is bad, or its the wrong one. Not the wrong one if it has the nail head connector.
My suspicion with your temp gauge is that either the sender is bad, or its the wrong one. Not the wrong one if it has the nail head connector.
you can remove the wire from the throttle body to repair. remove spacer and gasket under it. where the wires meet the TBI is rubber/plastic block the slides out of the tbi unit. this will give some room to work with
Yup I’ve seen that you can do that. Decided I’m just going to leave the wiring part to the pros.
Going to check these out tomorrow. I’ll let y’all know what I find.
@dyeager535 i disconnected that wire connector. Gauge did move way past full. I guess that means it’s not the gauge and is something communicating with the gauge. Probably the sending unit?
Yep, correct sender. That looks pretty crusty, try your best to clean it off, sandpaper, steel wool, etc. Hit the connector terminal up too.
Once it's all clean test again. Dielectric grease is always a good idea on these connections.
Grounding that terminal to the block should peg the gauge in the opposite direction.
Do you have access to an IR temp gun? It's possible a PO put in the wrong thermostat (a 160*) or there isn't one.
If you had a scantool you'd be able to see what temperature the ECM says the engine is, and if it corroborates the gauge, you'd know thermostat is the likely issue. IR temp gun should give you an idea as well.
If you have an autozone nearby they may loan the scantool. OBD1 is getting long in the tooth though, so they may not. Wouldn't hurt to ask.
Next step for fuel gauge is to take a wire and ground the fuel tank sender wire at that connector. Gauge should go full empty with a good ground. If it passes that test, the problem is somewhere closer to the tank than that connector. I can't recall the color of the wire that is fuel gauge (vs fuel pump) if you search the board here I know it's been talked about. Or someone else will remember. Really shouldn't matter with the key in run to try both, as the pump won't be getting power as long as the key isn't cycled.
Once it's all clean test again. Dielectric grease is always a good idea on these connections.
Grounding that terminal to the block should peg the gauge in the opposite direction.
Do you have access to an IR temp gun? It's possible a PO put in the wrong thermostat (a 160*) or there isn't one.
If you had a scantool you'd be able to see what temperature the ECM says the engine is, and if it corroborates the gauge, you'd know thermostat is the likely issue. IR temp gun should give you an idea as well.
If you have an autozone nearby they may loan the scantool. OBD1 is getting long in the tooth though, so they may not. Wouldn't hurt to ask.
Next step for fuel gauge is to take a wire and ground the fuel tank sender wire at that connector. Gauge should go full empty with a good ground. If it passes that test, the problem is somewhere closer to the tank than that connector. I can't recall the color of the wire that is fuel gauge (vs fuel pump) if you search the board here I know it's been talked about. Or someone else will remember. Really shouldn't matter with the key in run to try both, as the pump won't be getting power as long as the key isn't cycled.
No IR temp gun or scan tool. Although I'm thinking it'd be a good investment to get one. Someone suggested this one at some point. May have been this thread or a different one. I'll clean the connection up and see if I get lucky.
When you say take a wire and ground the sender wire...do you literally mean stick the end of a wire into the terminal on that 2 wire connection running towards the engine? And I do this with the key on but engine not running?
And so I understand what I'm looking for: we've already verified that its stuck below empty with connector plugged in and unplugging sends it way past full. Now if I ground the connection after unplugging, I'm seeing whether it goes back past empty
Strange development on the temp gauge. Cleaned off the connections, took it out for a spin to warm it up and got to 210. Was about to start celebrating but when i looked down again and it dropped to 155. It seemed like it happened the first time I slowed down after reaching 210...
Yes to a wire from the connector to ground...it's unlikely you'll see any change (It should go to where you normally see it, below empty) but this just proves beyond a doubt there is nothing wrong with anything forward of that connector.
Somewhat odd that there would be a short to ground at the tank, but things happen, especially if someone was in there messing around like you said. Often the problem is no ground back there.
If you have stock exhaust, depending on your size, with a flashlight, you may be able to crawl under the passenger side just forward of the rear axle. Im able to sit up in this area, and it gives me a very good look at the top of the tank. The wires go to the center, and while some hoses will somewhat be in the way, if there is a pinched wire you may see it this way.
I'd be inclined to swap the temp sender at this point, unless you definitely expect to get a scantool, as that or an IR temp gun is about the only way you will be able to check gauge reading vs actual temp.
I can't vouch for these guys, hadn't popped up on my radar before. A bit more work than a dedicated scantool. http://www.reddevilriver.com/site/4...l=http://www.reddevilriver.com/aldl.html#2625
Somewhat odd that there would be a short to ground at the tank, but things happen, especially if someone was in there messing around like you said. Often the problem is no ground back there.
If you have stock exhaust, depending on your size, with a flashlight, you may be able to crawl under the passenger side just forward of the rear axle. Im able to sit up in this area, and it gives me a very good look at the top of the tank. The wires go to the center, and while some hoses will somewhat be in the way, if there is a pinched wire you may see it this way.
I'd be inclined to swap the temp sender at this point, unless you definitely expect to get a scantool, as that or an IR temp gun is about the only way you will be able to check gauge reading vs actual temp.
I can't vouch for these guys, hadn't popped up on my radar before. A bit more work than a dedicated scantool. http://www.reddevilriver.com/site/4...l=http://www.reddevilriver.com/aldl.html#2625
Anybody have a part number for that temp sender? I’m having a difficult time tracking down the correct one. Keep landing on sensors, which looks different than the sender I’m trying to replace.
I did take a look at the top of the tank from behind the rear axle. All the wires seem to be fine. Could even touch the connection on top of the tank and everything seemed snug. Good idea to look from there though.
I did take a look at the top of the tank from behind the rear axle. All the wires seem to be fine. Could even touch the connection on top of the tank and everything seemed snug. Good idea to look from there though.
Talked to the shop who got the truck running initially. They said the fuel gauge actually worked when they were last in it. They dropped the tank and drained the old fuel. Said the gauge worked when they put it all back together...very odd because when we picked it up it didn't work. Since it'd been sitting for 10 years, we just assumed it hadn't been working before.
If the gauge works from the connector down on the frame rail (meaning you can max the gauge out over full and below empty), most likely something that happened when they were messing with it. If the wires aren't messed up on the outside, something internal to the tank is.
Could be something that shook loose, but man that's unlikely. Not a lot to those things. But why I'd want to verify the gauge works exactly as it should, before digging into the tank. That's not a whole lot of fun.
If you learn to use a multimeter you could also test the resistance on the tank side of that wire. It should be between 0 and 90 ohms with fuel in it. 0 means zero resistance to ground (in other words, connected to ground, one of the tests to do with the wire to the frame) and 90 means there IS resistance to ground...meaning it's not connected directly, as the sending unit is what provided the resistance depending on the float level.
Also, those fuel injected tanks break the plastic baffle inside, that can affect or harm the sender as well.
Could be something that shook loose, but man that's unlikely. Not a lot to those things. But why I'd want to verify the gauge works exactly as it should, before digging into the tank. That's not a whole lot of fun.
If you learn to use a multimeter you could also test the resistance on the tank side of that wire. It should be between 0 and 90 ohms with fuel in it. 0 means zero resistance to ground (in other words, connected to ground, one of the tests to do with the wire to the frame) and 90 means there IS resistance to ground...meaning it's not connected directly, as the sending unit is what provided the resistance depending on the float level.
Also, those fuel injected tanks break the plastic baffle inside, that can affect or harm the sender as well.
