Wiring up an oil pressure gauge added to a 914 center console

[Windisch]

OK, I've got a center instrument console for my 1974 914-4 that I've installed. I've replaced the clock instrument at the top of the console with a new 0-80 PSIG VDO gauge and now I need to hook it up and make it functional.

[The other two instruments (middle position oil temp, and lower position volt meter have been connected to the car's wiring harness that is already in place on my '74 model.]

I've installed a two-terminal (0-80 PSIG) VDO oil pressure sender (via a short length of braided steel sheathed tubing to a brass adapter fitting that I screwed into the stock oil pressure warning light orifice on the engine, next to the distributor) and connected the 'idiot' light to one of them. I now need to connect the other distal terminal (gauge pressure terminal) on the sender to the gauge itself.

My question is "How do I make this connection most easily?" Do I need to run a new wire from that sender terminal on the engine into the cockpit and then to the gauge? Or is there an existing wire on the stock harness somewhere that I can connect the sender terminal to (thereby saving myself a heap of difficulty snaking a wire along the central shift linkage tunnel to the console)?

Any expert insights into this mildly perplexing matter would be most appreciated. [FYI, I have the whole Porsche 914 series of shop manuals as well as most available conventional manuals on the car, but intuition tells me that this has already been done numerous times by others, so I'm eager to hear from those who've done this and can share their experiences with me.] Thanks.
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1973 Standard Beetle, 1974 VW/Porsche 914-4, 1.8 liter
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Der Volkswagen ist ein Ausdruck der deutschen Kultur der Allrad Art ...

[The only irrefutable evidence we have that intelligent life truly exists elsewhere in the Universe is the fact that so far it has NOT contacted humanity...]

[Starbucket]

After market gages like to be grounded near the sender not the body of the car.

[Windisch]

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you can certainly use one of the wires from the relay board to the front of the car, depending on how your car is equipped and what gauges you are using (for example if you do not have heat exchangers, you can use the wire for the heater lever which exits right near the console. Best to call for advice on this one.

[Windisch]

Well, this post isn't strictly about wiring-up the two-pole engine oil sender... Rather it's more about installing that sender, given the challenge of adding a two-pole (one to oil pressure idiot light, the other to an oil pressure gauge) sender to the engine, given that damnably small access hole where the idiot light sender normally screws in (using a 24mm deep socket to remove it).

See the attached three images that show AUTO ATLANTA's nifty oil pressure sender extension hose assembly. These are available from several other sources, of course, but interestingly their use also involves some challenges of their own, since that damnable pressure sender hole is so small (and submerged inside the outer sheathing).

Actually, you'll need to have a cut-away 14mm deep-socket, first of all, in order to install the correct brass adapter required in the sender hole after you've remove the OEM idiot light sender. But then you'll need two of those SAME brass adapters (stacked on top of each other) in order to get the extension hose collar above the sheathing (otherwise it's tough to be able to get a suitable wrench on it for tightening purposes). Then, if you're not careful, it's all too easy to accidentally drop an adapter down onto the engine itself (requiring fishing it out with a long-nose forceps or hemostat). [If you smoke 'funny stuff', no problem finding a hemostat...er...'roach clip.'

Assuming you aren't tres clumsy (like me...I was born with 5 thumbs), that's most of the 'tough' work required. The next step is to determine how long you need to cut some wire lengths to attach to the two sender poles (the 'WK' terminal goes to the idiot light, the 'G' means 'Gauge, NOT 'GND'). After this, the new two-pole sender needs to be grounded to the engine casing (which I was able to do easily enough...see attached images).

Since there's already an idiot light wire going directly to that warning light on your instrument panel, the only thing left to do is run a separate wire from the 2nd sender pole ('G') to your oil pressure gauge, up in the cockpit. [Every time I am forced to go into my car's center tunnel, I usually make sure I've installed a couple of extra spare wires in there, running from the engine bay to the instrument panel outlet., so as to save a lot of needless extra work.]

Make sure you use the appropriate copper washers (as and where appropriate) on the adapters and DO NOT over-torque them. Since the adapters use tapered threads, over-torquing can really screw things up.

Grounding the sender body to the engine casing IS necessary and use of as extension tube assembly like mine (AUTO ATLANTA) enables the new two-pole sender to be installed anywhere with reach of the attached hose.

As you all know, working on a 914, with its mid-engine access, is somewhat akin to intimate dealings with the feminine gender! Either one is never easy to 'work on' and always complicated (insincere apologies to any female 914 owners in the audience, but experience has amply shown it's TRUE!). Since my car's name is 'JEZIBEL': QED!

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1973 Standard Beetle, 1974 VW/Porsche 914-4, 1.8 liter
----------------------
Der Volkswagen ist ein Ausdruck der deutschen Kultur der Allrad Art ...

[The only irrefutable evidence we have that intelligent life truly exists elsewhere in the Universe is the fact that so far it has NOT contacted humanity...]