Gauge or Sending Unit?

[BadBahner]

I have a 0 psi reading on my Engine Oil pressure. It is totally dead, no movement at all. How can I figure out if it is a sending unit or if it is the gauge?
I have a BBC with electronic SU and VDO gauge.
Thanks,
Eric

[1HOTGMCJET]

Take and ground the sending unit wire directly to the block - gauge should pin - this would indicate bad sending unit - if not, probably the gauge - good luck! :)

[lilrick]

or faulty wiring

[Taylor LP]

or no oil pressure :jawdrop:

[BadBahner]

Take and ground the sending unit wire directly to the block - gauge should pin - this would indicate bad sending unit - if not, probably the gauge - good luck! :)
Ok I grounded the sending unit to the block and it did peg the gauge. Now what? Is this a special sending unit for the gauge? Is there a marine version of the sending unit or can I go to any auto parts store? I have no experience with oil pressure sending units so if anyone has ever replaced one I would sure appreciate some assistance. Trying to get it fixed so I can go to CBBB this weekend. Thanks everyone.
Eric

[Oldsquirt]

You need to match the sending unit to the gauge. You need to know what brand gauge you have and the pressure range(0-80, 0-100). Are there any numbers, brand name on the sending unit?

[lucky]

or faulty wiring
i found at the breakers - on ollllllld jet boats its common for the wire to become brittle - so if you have bouncy gauges - check grounds at the connection - just a fyi

[Taylor LP]

You said you had a VDO gauge, you need to get a VDO sender. Most VDO gauges are either 0-70 or 0-150 psi. Markings on those senders will be 0-5 bar or 0-10 bar, and they need to match the gauge. I have a couple good used VDO senders, if you need one, PM me and I might be able to save you some bucks.
The usual problem with these is that someone fed +12 volts to the sender, either by a short or incorrect connection at the gauge. Since you said the gauge still pegs when you ground the sender, be sure and check for any loose wires or terminals touching each other at the guage or engine junction block. These VDO senders seldom fail on their own. Don't want to puff another $ender.

[wet77]

Had a problem like that on my 460 I had, I just hooked up a universal wet gauge with the plastic lines going to the motor for $10 at a local parts store and found out for sure if I had oil PSI in the motor ;)
Fixed the problem (bad sender in the other gauge) and kept the wet gauge in the tool box for the car, truck, boat or whatever else I would need to check :D
Just a thought :idea:

[BadBahner]

You said you had a VDO gauge, you need to get a VDO sender. Most VDO gauges are either 0-70 or 0-150 psi. Markings on those senders will be 0-5 bar or 0-10 bar, and they need to match the gauge. I have a couple good used VDO senders, if you need one, PM me and I might be able to save you some bucks.
The usual problem with these is that someone fed +12 volts to the sender, either by a short or incorrect connection at the gauge. Since you said the gauge still pegs when you ground the sender, be sure and check for any loose wires or terminals touching each other at the guage or engine junction block. These VDO senders seldom fail on their own. Don't want to puff another $ender.
Thanks Taylor,
I have a 0 - 80 VDO. Do you have a sender for that one?
Eric

[Taylor LP]

I think the 0-80 was an newer VDO, not sure. Do you have any pix of the gauge or sender, or maybe the markings on the sender? Does it look the same as the attached pix below If it's a common VDO the 0-5 or 0-10 bar markings will be on the hex part of the sender, and the body will be steel gray and round with the terminal end flat.
The newer ones use a sender that is tapered on the end and have zinc plated (yellow) housing.

[BadBahner]

I think the 0-80 was an newer VDO, not sure. Do you have any pix of the gauge or sender, or maybe the markings on the sender? Does it look the same as the attached pix below If it's a common VDO the 0-5 or 0-10 bar markings will be on the hex part of the sender, and the body will be steel gray and round with the terminal end flat.
The newer ones use a sender that is tapered on the end and have zinc plated (yellow) housing.
I will post pics later today. The sender is painted the same color as the block as it is the oem one. I have not pulled the sender out either but I did check all the wiring and it is good.
Thanks for your help and stay tuned. If you have a sender I will buy it.
Eric