Is it possible to have an OBD2 port in an mTDI AHU on an 87 VW Vanagon Syncro ?

gaucho

New member
Joined
Apr 7, 2017
Location
Miami
TDI
1.9
The engine swap on my 87 Vanagon Syncro does not appear to have included an OBD2 port and I would really like to replace the 6 mechanical engine gauges that monitor the mtdi engine but take a large portion of my dashboard with an app that can run on an iphone or tablet (like DashCommand) and take its info from an inexpensive bluetooth OBD2 reader connected to an OBD2 port. This engine was previously in a 1998 Jetta and I assume it must have had an OBD2 diagnostic port since it was made after 1996. Is there a wire/s somewhere that would allow me to get OBD2 data to an obd2 port?

I had a previous tdi powered vanagon (not an mTDI) that had an OBD2 port and allowed me to use a scangauge which worked well.
Any assistance or suggestion if that is possible or pointing me in the right direction would be appreciated. This is my first post here although I have owned 3 tdi powered vehicles.
Thank you
Drew
 
Last edited:

Vince Waldon

Top Post Dawg
Joined
Apr 25, 2009
Location
Edmonton AB Canada
TDI
2001 ALH Jetta, 2005 BEW Wagon
Having an mTDI pump generally means no ECU...and if there's no ECU there's nothing to speak OBD2 to the outside world, port or no port. :)

Does your vehicle have an ECU?

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gaucho

New member
Joined
Apr 7, 2017
Location
Miami
TDI
1.9
I appreciate your reply even if not what I wanted to hear. I do not see anything that resembles an ECU but will look again.

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Vince Waldon

Top Post Dawg
Joined
Apr 25, 2009
Location
Edmonton AB Canada
TDI
2001 ALH Jetta, 2005 BEW Wagon
Unfortunately for you whoever decided on your engine almost certainly wanted to delete the one thing you're looking for... hence the mechanical-only injection pump. :)
 

d24tdi

Veteran Member
Joined
Jan 6, 2019
Location
MT
TDI
97 AHU in a Toyota pickup
I suppose the technical answer to your question is that you could add an OBD port even with a mechanical pump running the engine, if you wanted to badly enough and were ready to do (or pay for) the work. Presumably if it was originally an electronic TDI engine that was converted to mechanical operation, it still has the boss in the block for the crank position sensor and the tone ring on the crank, and might even still have the sensor there with wires cut or unplugged, so that could give you RPM. Provisions for other engine sensors that feed the ECU probably also still exist (ECT sensor, etc.) Optical or magnetic pickups for vehicle speed sensing exist that you could send to the ECU at the right frequency with a little homework. You could find a used engine harness and ECU to start with, reconstruct enough wiring to get the ECU to wake up, receive the few signals from the needed sensors, and output live data to an OBD reader to run your gauges. Some folks have done this type of thing on engine swaps into newer cars that depend on the original ECU functioning in a limited capacity to run gauges and handle things like ABS or stability control functionality, alternator charging, etc, where running without a dummy ECU still in place would cause problems with those systems.

So it could theoretically be done. But it almost certainly would be the most labor intensive available way to get a good set of gauges in your conversion. ;)
 
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