gauge and sensor ?'s

[psycho91]

Ok so I have replaced my temp sensor and my gauge still wont work, it just sits all the way to the right, after changing it though when the key is turned on it will move just a little to the left, what could be wrong

Also my oil pressure gauge does the same thing, except when I changed it it was sitting about half way and then when I turned the key it went all the way back to the right and has sat there since, my problem may be that idk what unit I actually need, my plug has 2 spots for blade terminals and also a spot in the middle for what looks like a pin of some
sort, I go to the parts store and all they have are one blade and 2 blade units, the one blades are all for a gauge and the 2 blades are for a light, well I have a gauge but my plug is for 2 terminals as already stated so I got one that was 2 bladed but it doesn't work, any suggestions, all this is driving me nuts

 

[Boone83K10]

sounds like a grounding issue. If it's pegged to the max...

 

[psycho91]

I wouldn't know where to look for the ground

 

[Driver4r]

Ground out the temp guage wire, and if it goes to full, then the senser is bad. Make sure you have the right one(guage version).

 

[psycho91]

It stays pegged to the right all the time whether it's plugged up or not

 

[chengny]

Also my oil pressure gauge does the same thing, except when I changed it it was sitting about half way and then when I turned the key it went all the way back to the right and has sat there since, my problem may be that idk what unit I actually need, my plug has 2 spots for blade terminals and also a spot in the middle for what looks like a pin of some
sort, I go to the parts store and all they have are one blade and 2 blade units, the one blades are all for a gauge and the 2 blades are for a light, well I have a gauge but my plug is for 2 terminals as already stated so I got one that was 2 bladed but it doesn't work, any suggestions, all this is driving me nuts

That's all one sentence. Difficult to read. I think this is what you are asking about:

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This is the sender you need to drive the oil pressure gauge:

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It provides a variable resistance to ground - in relation to engine oil pressure (0-60 psi).


As far as grounding the instrument panel, here is the main ground bus block:

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Check that the connections are all on and tight.

 

[psycho91]

Can't use that one, my plug has spots for 2 terminals and a pin, I think I'm just going to put an aftermarket gauge in cause no one knows anything about this

 

[chengny]

That didn't used to have a diesel in it did it?

 

[psycho91]

No, originally had a 305

 

[HotRodPC]

Can't use that one, my plug has spots for 2 terminals and a pin, I think I'm just going to put an aftermarket gauge in cause no one knows anything about this

Wow, you give up pretty easy. Not sure where you got "cause no one knows anything about this". We know plenty about this. It's a matter of troubleshooting. And it's also a matter of determining bad gauge, bad sender, tracing wire, checking or suspecting printed instrument circuit, etc. NO, it's not going to be as easy as looking at a fuse and saying YES it is, NO it isn't.


FIRST OFF, what we do KNOW. Is that a pegged gauge means the gauge is getting a full ground somewhere. That can be from inside the gauge internally, all the way to the sending unit, but somewhere, it IS grounded out.

 

[psycho91]

I haven't tried resetting the gauges or anything, ill also have to trace down the wires, sounds fun, how would I know if the printed circuit is bad, all my other gauges work

 

[HotRodPC]

OK, I'm back. Now that we get that adjustment made, that NOONE knows anything about this, Chegny is probably in the top 3 of 1 who would KNOW where to start with troubleshooting an this. Also, others will come in and one person gets another persons mind working, and other suggestions will come too.

Believe it or not, these gauge issues are probably one of the more complex issues you will deal with on an 86 or older square. I say 86, cuz in 87 TBI came about with ECM, and that can be pretty complex to troubleshoot too.

Also, keep in mind, we're not looking at this vehicle. It's not in front of us, it's in front of you. So assumptions will likely be made since we don't have the vehicle, and going to depend on your feedback and communication to help you out. But, if you're willing to do the leg work, I'm certain we'll get to the bottom of it. I might need a gauge, maybe even a printed circuit, but it can be handled. A cheap gauge trio for $40-$50 is also another option if you don't mind them not looking OEM and want to install them.

So onto the issues.

You said you replaced the sensors in both Temp and Oil??? Just so you know, and to make sure you got the right parts. There is a difference in SENSOR, Gauge SENDER, and Warning/Idiot Light SWITCH. Are you certain you got the right parts? The Gauge SENDER and Idiot Light SWITCH do look extremely similar. Almost noway to tell the difference without knowing the part # to the part.

Hey Jerry (Chengny), How about this, being he's mentioned BOTH Temp and Oil were both pegged, I know it's sure possible to have other issues, but what are the odds that 2 gauges, 1 on top of the other is also grounded out??? I think I'd just about make the first suspect problem is a shorted out Printed Circuit??? Maybe even right at the plug into the cluster??? I do know one track of circuit goes one direction, and one goes another, but still, some corrosion or something burnt right at the connector to the printed circuit, could certainly ground out 2 gauges. What doens't make sense in that scenario though, is why woudl the Oil Pressure change after a SENDING unit swap???

 

[HotRodPC]

I haven't tried resetting the gauges or anything, ill also have to trace down the wires, sounds fun, how would I know if the printed circuit is bad, all my other gauges work

Many times in printed circuit you'll see a burn or wear off of the track. But, before we have you tearing into your dash, we'll get Jerry and maybe a couple other guys with suggestions. It does sound as if the cluster might need to come out. And sometimes, you can't see anything obvious with printed circuit, so then it's process of elimination. Test everything else, and KNOW it's good, and when the gauge doesn't work still, then at that point, it' safe to ASSUME the printed circuit or connector has a problem.

 

[notverrysmart]

if your careful with a meter and don't scratch the copper you can ohm check between traces to see if you have a short somewhere on the pcb. would still require the removal of the gauge cluster from the dash though

 

[psycho91]

Yeah IV already had to lube the speedo cable so I know its a pain in the ass, ill have to check that next weekend, I'm not sure if we even got the right unit as part store only have 2, the one blade for a gauge or the 2 blade for a light, but as IV already stated my plug has spots for a 2 blade unit and it has a spot in the middle for a pin, I'm guessing its the gauges or the circuit, how hard is it to put in aftermarket gauges in the place of the stock ones