New oil pressure sender faulty?

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Stephan D

Stephan D

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Got a new oil pressure sender unit for the original gauge.

Just wanted to test it before installation, but it´s an open circuit,
is it faulty unit?

(Tested my ohmmeter with a small lamp, and it showed 5 ohm OK.)
IMG_6645.JPG
 
Two types of senders - one for the light, one for the gauge. If you can put 30 psi of air to it and it shows 0 ohm, it's the wrong one.
 
Demonic said:
Two types of senders - one for the light, one for the gauge. If you can put 30 psi of air to it and it shows 0 ohm, it's the wrong one.
Click to expand...

No light, just gauge.

No compressed air available, hmmm.

The workshop installed an incorrect oil pressure switch and connected it to the gauge that pegged.
 
Stephan D said:
No light, just gauge.

No compressed air available, hmmm.

The workshop installed an incorrect oil pressure switch and connected it to the gauge that pegged.
Click to expand...

That's because they installed a switch. What you have is not a switch, but a sending unit for a gauge. It has a basic rheostat inside. The more pressure applied, the more of a connection is given and the gauge moves up. It should be an open connection when checked as you have.

Also, I'll add this since it could be relevant. I just recently went through THREE bad brand new oil pressure switches (for a light) for my slant six. All Standard Ignition products. Part number PS16. First one never worked. Second one worked for a short time and failed leaving the light on. Third one worked for two days and failed where the light never came on. So.....I hawked eBay and got an NOS Chrysler pressure switch and all is well. I never thought I'd say this but Standard Ignition SUCKS. Thanks, China.
 
Yup, junk in the box. Way more now than 20 years ago.
 
RustyRatRod said:
That's because they installed a switch. What you have is not a switch, but a sending unit for a gauge. It has a basic rheostat inside. The more pressure applied, the more of a connection is given and the gauge moves up. It should be an open connection when checked as you have.

Also, I'll add this since it could be relevant. I just recently went through THREE bad brand new oil pressure switches (for a light) for my slant six. All Standard Ignition products. Part number PS16. First one never worked. Second one worked for a short time and failed leaving the light on. Third one worked for two days and failed where the light never came on. So.....I hawked eBay and got an NOS Chrysler pressure switch and all is well. I never thought I'd say this but Standard Ignition SUCKS. Thanks, China.
Click to expand...

Thanks!

So it´s not possible to check the sending unit resistance just on the bench as it will show an open connection as it does, right?

(Good to know about quality issues as well, that might show up after installation then...)
 
Stephan D said:
Thanks!

So it´s not possible to check the sending unit resistance just on the bench as it will show an open connection as it does, right?

(Good to know about quality issues as well, that might show up after installation then...)
Click to expand...

Sure it is. You're doin it. lol The only other way would be if you had air pressure. Which brings me to my next question. WHY do you have an old car and are working on it and you have no compressor "OF SOME SORT"? That should be as important as bringing your balls to the party. Entry level portable compressors are cheap. There's no excuse for not having one.
 
RustyRatRod said:
Which brings me to my next question. WHY do you have an old car and are working on it and you have no compressor "OF SOME SORT"? That should be as important as bringing your balls to the party. Entry level portable compressors are cheap. There's no excuse for not having one.
Click to expand...

I really appreciate all your help, but living in an apartment with a garage below where NO workshop activities are allowed puts a lot of limitations to my possibilities.

 
Just to clarify, someone above mentioned "light". I believe they are saying it's for the oil warning light on the dash(factory style). Not for "back lighting" on a psi gauge. Hope that helps.
 
It only takes a few minutes to change it out. That's the fastest and easiest way to test it.
 
cudamark said:
It only takes a few minutes to change it out. That's the fastest and easiest way to test it.
Click to expand...

Yes, but the current one is a very misfit mechanical Bosch hanging under the instrument panel, I want to get the original gauge working again with a new sender, thats me. :)
 
You should have tagged this onto to your original thread

1...If you tested the sender as you say, and did it correctly, that is NOT the correct resistance. All gauges using a sender---temp, oil, and fuel--pretty much use the same sender resistance ranges. Here they are photoshopped into the gauge tester:

Your results mean, if done correctly, that either the sender is defective or it is the WRONG sender (in the box) regardless of what was PRINTED on the box. It might be good to round up a friend with another multimeter and verify that your meter is OK and accurate

c-3826-jpg-jpg.jpg


Look at the yellow text, bottom left.

74 ohms is Low end of gauge scale
23 ohms is Middle of gauge scale
10 ohms is High end of gauge scale

So the sender at rest, whether temp sender or oil sender should read 74 "or more."

2...If you are going to keep your truck search around and get a repop of the factory service manual. Nowadays there might be someone selling these in electronic pdf, so you don't even have to ship it.....just download it. You may have to pay for that

3....Identify the bulkhead connector cavity for the oil sender wire.

4...Connect a 12V test LAMP (not LED) to the wire you have identified and with the key in "run" (engine stopped) probe the suspect wire. If that is the correct sender wire, you should get two results---the gauge should move some while the lamp is connected, and the lamp should "pulse" on/ off

5...At this point you should be able to wire it up and get good results. If you can round up some test resistances shown above, you can test any/ all of the gauges (except ammeter) using those resistances.
 
Last edited:
67Dart273 said:
You should have tagged this onto to your original thread

1...If you tested the sender as you say, and did it correctly, that is NOT the correct resistance. All gauges using a sender---temp, oil, and fuel--pretty much use the same sender resistance ranges. Here they are photoshopped into the gauge tester:

Your results mean, if done correctly, that either the sender is defective or it is the WRONG sender (in the box) regardless of what was PRINTED on the box. It might be good to round up a friend with another multimeter and verify that your meter is OK and accurate

View attachment 1715642026

Look at the yellow text, bottom left.

74 ohms is Low end of gauge scale
23 ohms is Middle of gauge scale
10 ohms is High end of gauge scale

So the sender at rest, whether temp sender or oil sender should read 74 "or more."

2...If you are going to keep your truck search around and get a repop of the factory service manual. Nowadays there might be someone selling these in electronic pdf, so you don't even have to ship it.....just download it. You may have to pay for that

3....Identify the bulkhead connector cavity for the oil sender wire.

4...Connect a 12V test LAMP (not LED) to the wire you have identified and with the key in "run" (engine stopped) probe the suspect wire. If that is the correct sender wire, you should get two results---the gauge should move some while the lamp is connected, and the lamp should "pulse" on/ off

5...At this point you should be able to wire it up and get good results. If you can round up some test resistances shown above, you can test any/ all of the gauges (except ammeter) using those resistances.
Click to expand...

Thanks for all help!
(I have not tinkered with cars in 40 years,
so the learning curve is steep...)

Problem solved - We have pressure!
20201204_115307[1].jpg
 
Tooljunkie said:
Yup, junk in the box. Way more now than 20 years ago.
Click to expand...
you can say that again , have a buddy with a parts store , it is just insane the amount of defective new parts returned , then there is the failure rate if the parts do work for a while . Standard , do they still carry 2 lines of products ? junk and worse junk . that's what we get for going the cheapest route
 
67Dart273 said:
So what did you do?
Click to expand...

My goal was to get the original gauge to be operational again, as the previous owner had installed misfit aftermarket mechanical temp and oil pressure gauges below the dashboard.

No original senders where in place.

I asked my workshop to reconnect the original gauges, which failed big time, none of their solutions worked, they had installed an oil pressure switch, which off course didn´t work with the gauge.

Bought a correct sender for the oil pressure gauge, wanted to check the sender before installation, but that was not possible without pressure of some sort, which I didn't have.

Anyway, installed the new sender and located the right wire, success!

Water temp still to fix, shouldn't be any problem I hope, got a new sender in my office...
 
The temp senders are crap now too. I have been through a few, bad out of the box. You can test them as in post #16. If it doesn’t read about 70-80 ohms at room temp, it’s bad.
 
RustyRatRod said:
That's because they installed a switch. What you have is not a switch, but a sending unit for a gauge. It has a basic rheostat inside. The more pressure applied, the more of a connection is given and the gauge moves up. It should be an open connection when checked as you have.

Also, I'll add this since it could be relevant. I just recently went through THREE bad brand new oil pressure switches (for a light) for my slant six. All Standard Ignition products. Part number PS16. First one never worked. Second one worked for a short time and failed leaving the light on. Third one worked for two days and failed where the light never came on. So.....I hawked eBay and got an NOS Chrysler pressure switch and all is well. I never thought I'd say this but Standard Ignition SUCKS. Thanks, China.
Click to expand...

U nailed it , Standard ignition is junk now
 
Mike69cuda said:
The temp senders are crap now too. I have been through a few, bad out of the box. You can test them as in post #16. If it doesn’t read about 70-80 ohms at room temp, it’s bad.
Click to expand...
Best to find [ OLD ] NOS on ebay or swap meets new stuff is junk
 
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