[T3] On my 73 square

[William Jahn]

I do have a few analog volt/ohm meters that for these sorts of tests seem
to find things a digital meter might be to quick to point out.

On Sat, Sep 14, 2019 at 9:35 AM Jim Adney <jadney at vwtype3.org> wrote:

> On 13 Sep 2019 at 16:11, William Jahn wrote:
>
> > I will check the voltage at the ECU from the power relay , to be
> > honest after I fixed the relay plugging in the air temp it seems to run
> > even worse and the same with it unplugged.
>
> Fixing the supply voltage should have made it run leaner, which normally
> would have made things better. Your observation that it's worse now, makes
> it seem even more likely that it's running excessively lean, which is
> consistent with removing the air temp sensor, which richens it up a bit.
>
> This is also consistent with the problem starting as the engine and head
> sensor warm up and lean out the mixture.
>
> Things that will make it run lean:
>
> Vacuum leaks at the air runner to head connections. (I'm pretty sure you
> have fixed those, but did you get both surfaces nice and clean and flat
> before you installed the new gaskets? You could also check with some
> propane there.)
>
> Low fuel pressure (measure while driving)
>
> Bad connections in the injector circuits (Measure the resistance from the
> ECU injector pin to the separate ground pin on the same connector, should
> be ~2.5 Ohms. Also make sure the brain connector fingers are close enough
> that they will make good contact with the brain circuit board. I have some
> little bits of brain edge connector that you could use to test the
> tightness of
> each conector pin.)
>
> Leaky aneroid in the pressure sensor (try a different, late (116) E
> pressure
> sensor) This is rare, but it happens.
>
> That's all I can think of at the moment, but there may be more.
>
> > I don't have a problem spending the extra time checking wires with a
> > DVOM.
>
> The Bosch tester essentially gives you 1 or 2 extra hands. You can set the
> tester to look at a particular resistance path, while you watch the needle
> as
> you wiggle wires to look for intermittent/weak connections. It takes 2
> people
> to do this with a DVM.
>
> If you don't have the Bosch tester, get a friend to help.
>
> --
> *******************************
> Jim Adney, jadney at vwtype3.org
> Madison, Wisconsin, USA
> *******************************
>
> _______________________________________________
> VWType3.Org mailing list - type3 at vwtype3.org
> To unsubscribe or change subscription options, visit:
> http://lists.vwtype3.org/listinfo.cgi/type3-vwtype3.org
> If you need more help, contact: gregm at vwtype3.org
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.vwtype3.org/pipermail/type3-vwtype3.org/attachments/20190914/0d6d793b/attachment.html>