How fast should gauges move when grounded?

[DC_Gearhead]

Quick and easy question: When grounding the oil pressure and temp sending unit leads, how fast should the gauges peg? I ask because mine take about 10 seconds to peg and jerk a little. I takes the same amount of time for them to zero out. I’m assuming this is not supposed to be slow since I am reading that when you turn your key to ON, the oil pressure gauge should peg and drop to zero. Mine would take 20 seconds to do that!!

All of my gauge pointers are close, if not rubbing, the dial face of gauge. Sounds like I need to have Classy do a rebuild but want to get confirmation before taking my rig offline for a month.


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[ared77]

I know on old Mustangs it's quick, maybe a second or two. Bronco should be the same I'd think.

 

[DirtDonk]

When grounding the oil pressure and temp sending unit leads, how fast should the gauges peg?

Like ared said, I'd say about two or three seconds and smooth. They're dampened, so unlike aftermarket gauges they're not going to jump to their peak immediately.

I ask because mine take about 10 seconds to peg and jerk a little. It takes the same amount of time for them to zero out.

Yep, too long. And the jerking is showing something, although I have seen perfectly good gauges do a gentle jerk or two, where it's more of a hesitation than a catch-n-release jerk.

I’m assuming this is not supposed to be slow since I am reading that when you turn your key to ON, the oil pressure gauge should peg and drop to zero. Mine would take 20 seconds to do that!!

Not that I know of. Never seen that on an old gauge.
A fuel gauge goes to it's current reading. If that happens to be empty it does not go up then down.
A temp gauge goes to it's current temperature reading. Or does not move if the engine is cold.
An oil pressure gauge should just stay at zero until the engine starts.
I know a lot of gauges do their dance when first energized, but I've never noticed a properly working Bronco gauge do that. Certainly don't remember it!

All of my gauge pointers are close, if not rubbing, the dial face of gauge.

Well that's not good. If just close, that should not have any effect. But if touching, that's a definite no-no that needs to be fixed.

Sounds like I need to have Classy do a rebuild but want to get confirmation before taking my rig offline for a month.

You could run the vehicle without gauges, or rig up some temporary ones.
Running without would not feel good to me! But rigging up something cheap to give me some peace of mind for the time it takes to get new ones would not be a lot of trouble.

Do the gauges eventually seem to read accurately?

Paul

 

[Broncobowsher]

I was going to say 2-5 seconds. Pauses as the rise would be normal. The IVR cycles and the gauge will only rise while the IVR is doing an "ON" cycle. The gauges are thermal, heating element heats a bi-metal spring deforming it. The more heat, the higher the gauge reads. That is where the old mechanical IVR has an advantage over the new solid state version, it is itself temperature compensating. I know The gas gauge is a steady input and watching it come up on a near full tank you can see it rise, pause, rise more, pause, rise a little more, and check a minute later it will finally settle.

I think your gauges are working correctly. So long as the pointers are not rubbing, they are good. They are very thin and easy to bend.

 

[Steve83]

...rise, pause, rise more, pause, rise a little more, and check a minute later it will finally settle.

I think your gauges are working correctly.

%) x2 The original description doesn't indicate any problem.

...when you turn your key to ON, the oil pressure gauge should peg and drop to zero.

No, it shouldn't move until the engine is running, and then it should respond to RPM (pressure from the pump rising & falling).

 

[m_m70]

so when you fill up, does your gas gauge take that long to peg and read full?

 

[DC_Gearhead]

so when you fill up, does your gas gauge take that long to peg and read full?

Works perfectly. I’ve only tested it at empty and 1/4, but i have a new fuel tank and sending unit.


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[DC_Gearhead]

I don’t know how to multi quote, so this goes to all above. Hahah.

It looks like the needles are all dragging on the face or just really rusty inside. These gauges haven’t been used for over 30 years. I’m a little nervous because I just started up my motor after rebuilding the top end myself (valve job, hardened seats, new springs, etc.). Seeing no oil pressure on the gauge made my heart drop. I tested the grounding out method and they all worked....slowly. I decided to start up my engine and run it for 20 minutes at idle to get the water pump flowing and thermostat opened up after the work. It ran like a top and sounded awesome with my new Duff duals with Flowmasters. With some tapping on the gauge the two gauges rose up. I can’t really see, but it looks like the needles are dragging on the face. If they aren’t dragging, they are REALLY close. I ordered two new $30 replacement gauges. Oil pressure and temp. I’ll install them this holiday weekend and hopefully that will fix the issue.

This is the first time I have had my bronco running since I went through the wiring and checked every connection, resistor, solenoid, regulator, sending unit, etc. Also verified correct sending units as well for temp and oil pressure. All should be good, but those are the famous last words of an idiot......hahaha

Hopefully it doesn’t seem like i disregarded the opinion that the gauges are working OK. I’m just overly sensitive about everything working well and the fact that I had to tap on the bezel to make them jump to the correct reading sucks. I will be driving this in the city with no shoulder to pull over on and no nice people to pull over and help me push if it breaks down. I want to know that the gauges are working perfectly. I do appreciate the advice.


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[DirtDonk]

I don't think we were saying yours are ok. From your descriptions they certainly don't sound ok! But the fact that when working properly they do still hesitate when climbing is true. Just not "notchy" or as slowly as yours, and certainly not that you have to tap on the gauge to get it to work.

And an oil pressure gauge that doesn't work at all is certainly grounds for not firing up the engine until it does. That would freak anybody out!

Good luck.

Paul

 

[DC_Gearhead]

I don't think we were saying yours are ok. From your descriptions they certainly don't sound ok! But the fact that when working properly they do still hesitate when climbing is true. Just not "notchy" or as slowly as yours, and certainly not that you have to tap on the gauge to get it to work.

And an oil pressure gauge that doesn't work at all is certainly grounds for not firing up the engine until it does. That would freak anybody out!

Good luck.

Paul

Good. I always hate when people ask advice and don’t even take it. I didn’t want to come across as one those guys.


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[DC_Gearhead]

Replaced the oil pressure and temp gauges with some from JBG. All work perfectly now. Oil pressure at 30. Much better.

When grounding out at sending unit they only take 3 seconds or so to peg.


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