I have a 2056 with a VDO oil pressure sending unit coming off the top of the engine, one end has the oil pressure the other the temp, it worked before removing it from original engine now it doesnt?
I hooked black and green wire to it, but getting no reading at all, do the sending units fail?

The VDO sending unit only gives you oil pressure and the idot light for low pressure, the oil temp sender is on the bottom of the engine( Taco plate).

Green/black is ALWAYS a temperature gauge wire. Green/red is ALWAYS a pressure light/gauge wire. If you have a light and a gauge, the extra wire isn't in the original harness. The light wire goes to the terminal on the dual sender marked "WK", and the new wire for the gauge goes to the terminal marked "G". The body of the sender MUST be grounded. The Cap'n

The unit is grounded since it comes out of the block,
extra wire?
Where are these letter markings you speak of?
thanks

If it's a VDO sender, it's marked on the face of the unit, right next to the posts. I've never seen or heard of a combination pressure/temperature sending unit. The Cap'n

I have the black and green wire and the red and green wire, currenlty the pressure sunding unit come up out of the top of the block near the distributor, it then has a "T" one ind attaches to the plastic hose that send the oil pressure to oil opressure guage, the other looks like a sending unit, I thought it was the temp guage, it may be the oil pressure sending unit?
If it is the oil pressure sending unit then where does the oil temp wire attach to? How do I check which sensor it is? At some point this last weekend the oil light wernt on in the car after making a few consecutive hard turns, so I assume the sending unit is the oil pressure unit??
Ugh, thanks for help. Matt

Since you have a T installed one side of the T goes to a pressure switch (normally
has a male connector on it) this is where the red/green wire goes. the oil pressure unit normally has a screw on terminal connection this is connected to
the oil pressure gauge. This wire is normally run seperate as the harness is not equipped for it. The oil tempature gauge is on the bottom of the engine and has
a green/black wire to it this wire has a extension on it to reach the sending unit,
this wire runs to a connector in the floor which the console is wired to.

PS
You can check the oil light out by turning on the key and grounding the red/green
wire this should turn on the oil light.

so I think I have the oil temp wire hooked up to the oil pressure light cennection (Male connection on T opposite oil pressure guage sending unit) I need to connect correct wire to sending unit, but then the green black wire which does have the extra wire extension on it and comes out of the firewall behind battery - where does that connect? Where is oil temp sending unit?

The oil temp sending unit is on the bottom of the engine on the drivers side. It's
mounted in a large round plate (Taco plate) with a metal cover over the sending unit with a openning it it to connect the green/black wire.