[Diy_efi] Reply to Mark Bacon's ground question

mbelloli at speedymotorsports.com mbelloli at speedymotorsports.com
Thu Jun 10 05:37:15 GMT 2004

Mark Bacon wrote:
>Can anyone tell me if the 727 ECM requires a chassis ground, and where the
>ecm gets the tach/rpm signal on the small/remote coil dist? I think my
>problem may be related.

>Thanks Mark

Mark I think I have your answer.  Do you have a tach filter???  Here is a
site with a pic of one.  Gm used these throughout the years.  And they've
cause me many problems over the years.  People remove them while doing
engine work and forget to reinstall them.  Then one day they finally
decide to bring there car in because it is running strangely.  If you look
at the tach signal with a DSO you'd see the problem.  Many of the eariler
carbureted computer cars had them in the line to the ecm, and not just the

Marcello <hexibot43 at hotmail.com>
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