Where the heck is the oil pressure sending unit?

[thescifiguy]

Where is the oil pressure sending unit located? I've checked everywhere on this web site. I've looked all over the engine. I'm a 4 time GT owner. I've pulled GT motors before. I feel like a complete retard for having to ask. I apologize for asking this stupid question.
Gordon

[jordan]

The oil pressure sending unit is on the manifold side of the engine below the manifolds on the block either on or in between cylinder 3 or 4 (I can't remember) it projects out of the block and it is a small stamped steel cup shaped part sometimes bare or with a black or orange rubber boot on it.

[BQS4]

If it's a standard sending unit, it should have one wire going to it. If it's a dual sender (for a gauge and idiot light) then it will have two wires running to it, and as Jordan has already stated, it's on the passenger side, back by the area where the bellhousing attaches. It will be the only thing back there with any wires running to it.

[jerseyopel]

Under no 4 aft cyl pass side

[broszzy]

yup what Jordan said about 8" back of the motor mount

Pat

[thescifiguy]

Arghhh, I'll bet that pesky heat shield was hiding it.

Thanks for the help guys!

Gordon

[MICAH1]

If you have used a timing light during your tune-up.... you looked right at it!!!

[tekenaar]

. . . already covered verbally, here it is in a picture!

[thescifiguy]

. . . merged into previous thread . . .

I don't have an oil pressure sending unit! Just a bolt. No wires in the vicinity. This discovery came about because I noticed that my pressure needle was pinning itself in the 5 range, as soon as I turned the key. Previous threads indicated that this was only possible if the wires were reversed on the sending unit. I don't have one! Who took it? Is it common/possible/likely that someone took it out and replaced it with a bolt to plug the hole? Did 72 GTs come without them? Do ya think the wires are jumpered together somewhere, causing the needle to pin? Where would the sending unit's wires enter/exit the firewall?

Gordon
"Bravely restoring, where no man has restored before!"

[jlthunder]

All Opels have an oil sending unit. If yours is missing, then someone removed it and replaced it with a plug. All Opels which have the gauge and light have the 2 wire unit. All others with only the light have the smaller one wire unit.

I believe the wire comes out of the firewall on the drivers side of the car. If the wire has been cut, I believe it will peg itself, but I'm going from memory.

Does the little light in the oil gauge light up when you turn on the ignition, but before you start the engine? Does it go out when the engine is running? This light is needed for the charging circuit to operate, otherwise you will be running off of the battery.

You need to install a sending unit so you know what your oil pressure is.

I don't have a schematic in front of me so I can't give you the wire colors.

[BQS4]

All Opels have one, either the simple one wire (for an idiot light) or the two wire (gauge and idiot light) one. GT's, Kadett Rallye's, Manta Rallye's and Sportwagons had the dual send, or rather two wire sender. A bolt there means the PO either didn't have another good sender or didn't care. If you want to get a new one, go to eGauges.com - VDO, Auto Meter, Defi, Isspro, Cyberdyne and Classic Instruments Gauges

[MICAH1]

Gordon,
This is on ebay.... better get it now..
eBay - opel oil unit, Parts Accessories - buy and sell on eBay Motors

[2 Fast 4 U]

Originally Posted by thescifiguy ......I don't have one! Who took it? Is it common/possible/likely that someone took it out and replaced it with a bolt to plug the hole?

maybe some little green fellow

[jlthunder]

Originally Posted by 2 Fast 4 U : maybe some little green fellow

You mean Kermit the Frog? Wait until Miss Piggy hears about this!

[namba209]

Originally Posted by thescifiguy Where would the sending unit's wires enter/exit the firewall? Gordon "Bravely restoring, where no man has restored before!"

Gordon, I was responding to this when the server went down, so I'll try again. First off the wires for the oil gauge go through the shelf above the clutch/brake pedal and in to the engine compartment with the rest of the front harness. Then they go across the firewall and down to the oil pressure transmitter. As was said before there are two wires, both are Light Blue/Green. Both go to the #6 pin on either the Red Instrument Panel connector to the lite or the Green Instrument Panel connector to the gage itself. On the transmitter, there are two connections, IIRC one is marked with a "W" or "Wk" and that is for the wire to the lite in the gage, the other is marked "G" for the gage wire. HTH.

[opelnut10]

The unit has two terminals, one has a spade terminal the other hnas an eyelet terminal than is held on by a nut. If you find two wire close togather and those colors you got it, if not you will have to locate the remains in the wiring bundle and make them up to go to the sending unit.

[markandson]

I have a question on my 2.2. I have the sending unit on the right side of the engine with two wires....normal. I also have a small sending unit with two male spade terminals sticking out of the timing chain cover. It is screwed into the hole where the old style oil relief valve is supposed to be. Does anyone know what this sender is?

[tekenaar]

Originally Posted by markandson I have a question on my 2.2. I have the sending unit on the right side of the engine with two wires....normal. I also have a small sending unit with two male spade terminals sticking out of the timing chain cover. It is screwed into the hole where the old style oil relief valve is supposed to be. Does anyone know what this sender is?

. . . more than likely an EFP (electric fuel pump) safety switch to turn off EFP when no oil pressure, i.e. engine stopped!

[2 Fast 4 U]

Originally Posted by 2 Fast 4 U maybe some little green fellow

Originally Posted by jlthunder You mean Kermit the Frog? Wait until Miss Piggy hears about this!

Nope.
little green fellow, thescifiguy [the scifi guy]

[thescifiguy]

Thanks for the info guys. Todd, at Opels Unlimited, told me to look for the wires in the vicinity of the starter, where the wire harness for the engine compartment stuff ends. Sure enough, there was a mystery wire snaking around the back of the engine........where it promptly disappeared into the insulating stuff on the firewall. A little tug and there they were: a spade tip and an eyelet tip at the ends of two wires.

By the way, this is the greatest website. I love it's ease of use and interconnectivity of it's various features. You guys who answer our questions are a great bunch! I was so crestfallen when the site went down and it said "my account" was suspended. I thought my questions were too stupid and I'd gotten kicked off the site!!! Thanks, to all, for all your help!

Gordon
"Bravely restoring where no man has restored before."

[2 Fast 4 U]

Originally Posted by thescifiguy .....I was so crestfallen when the site went down and it said "my account" was suspended. I thought my questions were too stupid and I'd gotten kicked off the site!!!......

The only way I know of getting kicked off this site is if you behave stupidly

[69opelgtfvr]

I'm pretty sure my oil pressure sending unit is bad because:

1) The Gauge at the dash reads "0" with engine running.
2) An Ohm Meter connected to the sending unit's terminals reads near-short (10 Ohms) with the engine off and "open" with the engine running.
3) The leads to the interior oil pressure gauge read ~1.5 KOhms.
4) The engine has been observed to be pumping oil, since it was leaking out of all the top-end gaskets (until they were replaced last month.)
5) Engine ground strap is in place.

Are there any other possible reasons that the gauge readings are zero, given this info?

[namba209]

If you are measuring between the two connections on the oil pressure transmitter, that's not the way to check it out. It should be either terminal to ground. The oil light switch terminal should read 0 ohms with the engine off and the gauge terminal should read high ohms. With the engine running, the oil lite switch terminal should read an open and the gauge terminal should read a lot higher and decrease as the rpm goes up, indicating a higher pressure as the rpm increases. Here's the approximate readings of the gauge side of the transmitter taken at the Green instrument panel connector, pin 6 to ground:
HTH.

1 bar = 45 ohms
2 bar = 77 ohms
3 bar = 113 ohms
4 bar = 145 ohms
5 bar = 175 ohms
gauge pegged = 250 ohms.

[69opelgtfvr]

Originally Posted by namba209 If you are measuring between the two connections on the oil pressure transmitter, that's not the way to check it out. It should be either terminal to ground. The oil light switch terminal should read 0 ohms with the engine off and the gauge terminal should read high ohms. With the engine running, the oil lite switch terminal should read an open and the gauge terminal should read a lot higher and decrease as the rpm goes up, indicating a higher pressure as the rpm increases. Here's the approximate readings of the gauge side of the transmitter taken at the Green instrument panel connector, pin 6 to ground: HTH. 1 bar = 45 ohms 2 bar = 77 ohms 3 bar = 113 ohms 4 bar = 145 ohms 5 bar = 175 ohms gauge pegged = 250 ohms.

Thank you for the info. I was connected wrong- but I just took measurements the right way:

>>>>>>gauge term.(thumbscrew) >>>>>light term.(spade)
engine.................................................. ...........
off.................10 Ohms.......................short
idle................84 Ohms.......................open

This seems to match up with your data for a good sending unit. I was hoping to get readings at higher RPM intervals, but I'll that try again later. It looks like I need to focus now on the instrument panel to see why I have no deflection on my gauge.

[Dennis Texas]

Originally Posted by thescifiguy . . . merged into previous thread . . . I don't have an oil pressure sending unit! Just a bolt. No wires in the vicinity. This discovery came about because I noticed that my pressure needle was pinning itself in the 5 range, as soon as I turned the key. Previous threads indicated that this was only possible if the wires were reversed on the sending unit. I don't have one! Who took it? Is it common/possible/likely that someone took it out and replaced it with a bolt to plug the hole? Did 72 GTs come without them? Do ya think the wires are jumpered together somewhere, causing the needle to pin? Where would the sending unit's wires enter/exit the firewall? Gordon "Bravely restoring, where no man has restored before!"

Well this post has made my day wondering if you ever had done any work on the opel Gt's you have had...3/4 the way back on passenger side right below the exhauste manifold is your unit it has two wires one for an idiot light for pressure one for the actual pressure range motor in running in. If it has a bolt then why does guage read when you turn key you have more than one issue here.... and the upside is everyone here will help you through it just details and pics are good.