Adding Gauges With
Jim Powell's Adapter


Some time ago I decided I wanted to add gauges to my M3. But I never liked the idea of having the oil temperature sender installed in place of my drain plug. It was a combination of the danger of having it
damaged and just the overall knowledge that this was a kludge. Clearly not something the factory would have done. But what to do? I couldn't realistically tap more oil ports into the engine. At first I
believed I could accomplish the level of install that I was looking for with Milos Klacko's oil cap. I bought one and had it tapped but it wasn't as clean an install as I wanted. Milos' oil cap is pretty cool and a great place to put a pair of lines for a cooler. It just wasn't right for sending units.

So I approached some local people with racing and BMW background about helping me design an adapter that would use a banjo bolt to extend the block tap that feeds the oil idiot light switch. This oil port would
allow me to re-install the stock idiot light switch, a VDO oil pressure sending unit and an E34 M5 oil temperature sending unit.

This procedure documents the use of this part to install gauges in my car. I expect this part will be marketed someday. I don't have any financial interest in this part any longer so take my enthusiasm for this installation method and part as a sincere belief that this is a solution that is superior to others marketed by BMP or VDO.

I will not go over installing gauges in-depth because it has been done many times and whatever vendor you buy this piece or gauge kit from will document installation step-by-step. I will loosely show you the steps involved as an overview for you to determine if you wish to do this upgrade yourself.

Examine picture 1 to see the parts involved. You should preassemble the gauges into your panel and construct wiring harnesses that can be disconnected for maintenance. I used a plastic faceplate and modified a spare sunglass holder to accept the faceplate. I attached the faceplate with superglue and black silicone.

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As first steps, remove the sunglass holder, OBC and glovebox. Also unfasten and open the wiring chase under the hood against the firewall. See pictures 2, 3 and 4 .

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Locate ground, switched 12V and switched, dimmed 12V. Wire power leads or harness to these points as directed by your gauge vendors instructions. Run signal leads for the oil pressure sending unit and oil temperature sending units through the firewall. This is pretty intuitive but can vary depending on model and year. Its generally easier to come through the passenger side. Feed the signal leads through the wire chase and dress each end with 1/4" wire loom as appropriate See picture 5.

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Install the 3 sending units (oil idiot light on bottom, oil temperature on top pointing back toward the firewall and the oil pressure sending unit on the angle) its important to always install the pressure sending unit within 45 degrees of vertical. Mounting it more horizontally will eventually lead to internal failure according to VDO. My adapter will mount this sender at 22.5 degrees. See picture 6.


Attach all of the sending unit leads. the stock idiot light switch harness plugs back in. I used an E34 M5 oil temperature sending unit and got the appropriate connector leads and boots from BMW out of their wiring harness repair kit and spliced those in. I also used a single connector boot from BMW to insulate, water proof and protect the wire to the oil pressure sending unit from VDO. See pictures 7 & 8 for details

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Picture 9 shows the gauges finished and installed in my '98 M3/4.

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If you find this part useful and are interested in obtaining one let me know and I will put you in contact with either the manufacturer or a distributor. Again, I have no financial connection to this part anymore. I've received my compensation for it and will not make another nickel if it sells millions. Good luck.

Jim Powell

Webmaster's Note: If you are interested in this product you can contact JT Designs at 760-736-9392 or via email at jtdesigns@jt-designs.com. Their home page can be found at
www.jt-designs.com