I doubt  sharing the same grounding point or wire would set a code, but
you never know with electronics either.
I would be really surprised it it did though.

I have posted about 60 times on various engine conversion groups to
never run lots of grounds through one wire, to copy what the factor did
as closely as you can, etc - like, do over-do it on grounds.  Redunant
ones even.
scott
www.turbovans.com
vanaogn engine conversions of any type you're willing to pay for.

neil N wrote:
> Hi all.
>
> My Jetta ABA 2.0 OBD1 conversion *was* running crappy. TPS and ECT
> weren't grounded. (D-oh!) Grounded them, engine runs better, but I
> still get error codes for TPS, ECT, and CMP.
>
> I conveniently wired the TPS, ECT, and CMP to share the same physical
> ground location.
>
> But..... Bentley shows them using grounds at (presumably) different locals.
>
> i.e. "Sensor ground", "MFI Motronic Multiport Fuel Injection"
>
> In archives, I read of Vanagon O2 sensor issues related to shield on
> coax and ground wire sharing the same physical ground location. This
> tipped me off.
>
> So.....
>
> If TPS, CMP, and ECT share the same ground connection (location),
> would this cause these error codes? Would sharing the same physical
> ground connection hinder performance and/or damage these parts?
>
> If I can leave it as is, I will. I don't understand what/where Bentley
> is referring to when using the various terms for different ground
> locations.
>
> "Fussy" questions, but it would be nice to get this "right".
>
> FWIW,  these are the only 3 error codes (so far --- ;^)
>
> Many thanks,
>
> Neil.
>
> --
> Neil Nicholson '81 JettaWesty "Jaco
> http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-gas-engines
> http://web.mac.com/tubaneil
> http://tubaneil.googlepages.com/
>
>
>