[alfa] Gallagher's Stalling Spider

["Michael Tiefenback" <tiefenback@xxxxxxxxxxx>]

---------- Original Message ----------------------------------
From: "Michael Tiefenback" <tiefenback@domain.elided>
Reply-To: <tiefenback@domain.elided>
Date:  Fri, 23 Jul 2004 14:07:50 -0500

> From: "John Gallagher" <gallagher41@domain.elided>
> Subject: [alfa] "Quit stalling, Spider.  Yah..."
>
> My '85 Spider has started stalling after a cold start.  The cold start
> injector works (it starts, runs at 900 rpm), but the rmp start to 
> decrease in a few seconds until the engine stalls.  Restarts fine, 
> then same problem on restarts until almost to operating temperature.  
> Suspect the aux air device.
> Any hints?
> Thanks.
>
> John

That is exactly the symptom the 1986 Spider had that I got for my sons to work on with me.  It required punching the throttle every few seconds until it got to operating temp.  Its O2 sensor read ZERO (0.01 V or so instead of 0.5'ish) until it was force-fed an appropriate aerosol hydrocarbon.  Then it asked for more by smoothing out and having the O2 readback go up toward 0.3 - 0.5 V.

Check for leaks in the hoses.  In our case, we (think we) found all of the leaks and fixed them, with no real improvement.  Ultimately we found  that the AFM had been previously "adjusted," with telltale foreign RTV traces on the cover.  We checked that holding the AFM door open to tell the ECU (to push more fuel) made things better.  Then we richened the AFM signal, loosening by 15-20 gear teeth the mainspring.  It runs quite nicely now.  No more cold stalling.  But look at the O2 sensor when it's running..  When it isn't, blow into (for instance) the AAD hose and see whether the engine holds pressure at all.  Listen for leaks elsewhere.  Our oil return line from the oil separator was really trashed.  And I replaced several other hoses just on general principle.  The AFM is what really did it for me, but your car might simply have bad hoses leaking "false air" in and diluting the fuel mix.

Look at Greg Gordon's www.oldebottles.com pages for a really nice L-jet tutorial that was massively helpful to me.

Michael
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