Hi Pat.

If need be, I'll add a ground from the frame to the engine. Something
to consider given that I've removed the Jetta engine from it's happy
home to a foreign land.

As for the wiring harness, here's a couple of possibilities in terms
of the physical integrity of the wiring harness.

I added a little length to some of the connectors in the wiring
harness. (in a "failed" attempt to position the large round 28 pin
connector on engine in a better spot.... away from the firewall) Plus,
quite a few wires had cracks in the casing and minor corrosion in the
strands. I cut and soldered new wire into those spots. In most cases
slightly large gauge wire.

I wonder if that added length (i.e. a few inches at most) caused this,
and/or the larger gauge?

I will double check the engine portion of harness. If need be, I'll
pull the larger portion of harness and re-check it again.

For sure. I have gone over this harness quite a few times. Newbie
learning curve for the most part. Never done anything like this
before!  --- :^)

Thanks Pat,

Neil.

On Sun, Jun 22, 2008 at 5:10 PM, pdooley <psdooley@verizon.net> wrote:
> If you're not sure what that means just add some extra ground wires between
> engine and body to get everything at the same potential (well, closer
> anyway).
>
> It sounds like your wire harness may have some physical integrity issues.
> I would check all the mechanical connections and check the circuit traces
> for proper resistance.
>
> You probably already checked all the grounds 10 times but maybe you missed
> something?
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Jim Akiba
> Sent: Sunday, June 22, 2008 5:58 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: Attn: Electrical Gurus (engine conversion grounds question)
>
> Keep in mind that in most vehicles, the sensor ground or returns are
> not chassis/battery grounds, they are reference grounds provided by
> the ECU to control/prevent voltage fluctuations and offsets... so you
> might not be doing the right thing by simply grounding them. Re-check
> the stock diagrams for this.. from the description (esp. with the
> mention of the ECU/engine management in the one description) maybe
> this is your issue.
>
> Jim Akiba
>
>
>
> On Sun, Jun 22, 2008 at 12:18 PM, neil N <musomuso@gmail.com> 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-engine
> s
>> http://web.mac.com/tubaneil
>> http://tubaneil.googlepages.com/
>>
>

--
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/