Date:         Mon, 23 Jun 2008 00:23:18 -0400
Reply-To:     Jim Akiba <syncrolist@BOSTIG.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Jim Akiba <syncrolist@BOSTIG.COM>
Subject:      Re: Attn: Electrical Gurus (engine conversion grounds question)
In-Reply-To:  <ac1f198b0806222122u33165ad9nc1886661b863f2b1@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

I just looked up a 95 jetta 2.0.  All of the sensors you mentioned are
grounded via body ground, so no worries there other than making sure
you have good ones.  It would be bad if they were "reference" grounds,
and body grounded instead.

Jim Akiba



On Sun, Jun 22, 2008 at 9:06 PM, neil N <musomuso@gmail.com> wrote:
> This is a large part of what I was curious about. The "sensor" ground.
>
> This makes sense. I'm sure that even in a pre '96 Jetta, the ECU is
> more than sensitive enough to judge if the sensor ground is "missing"
> on a given engine management component. Especially if it's providing
> the required sensor ground.
>
> I'll read the Bentley diagrams again and suss out where the ground
> (constant) comes off ECU. Thanks for pointer of where to start.
>
> Ah the poor, oft neglected ground..... --- ;^)
>
> Thanks Jim!
>
> Neil.
>
> On Sun, Jun 22, 2008 at 2:57 PM, Jim Akiba <syncrolist@bostig.com> wrote:
>> 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-engines
>>> 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/
>