[T3] 73 squareback auto trans FI question

Keith Park topnotch at nycap.rr.com
Tue May 17 18:01:56 PDT 2022

Never adjust the MPS for idle issues, you change the whole curve and unless
you have an AFR meter on it you have no idea where you are now, if its too
lean at speed you can burn it up or cause
Detonation.    Get the running mixture right, then idle is entirely bypass
air if everything else is right (like timing).


Topnotch Restorations
topnotch at nycap.rr.com
71 Squareback  “Hothe”
65 Notchback  “El Baja Rojo”
93 RX7  “Redstur”
13 Subaru Outback "Blendin"

-----Original Message-----
From: type3-vwtype3.org <type3-vwtype3.org-bounces at lists.vwtype3.org> On
Behalf Of William Jahn
Sent: Tuesday, May 17, 2022 1:32 PM
To: type3 at vwtype3.org
Subject: [T3] 73 squareback auto trans FI question

For some odd reason since it's been hot and dry 8% to 15% RH 90 degrees F.
I drove a 12 mile round trip and noticed the idle dropped 200 RPM. It was
always 1,000 in park and 800 in drive.  Then the next day drove it 1 mile
round trip and it was the same.

 I am not certain if it's the fuel the pumps say at least 10% ethanol. The
charging system works fine. It puts out 14 volts above idle meaning if I
place it in neutral @ 1000 RPM it would read 14 volts and while driving at
any speed it is 14 volts read at the battery and the battery even after a 1
mile drive reads 12.5 VDC.

 I thought perhaps since dry weather is less dense that might be the issue
since the MPS does not adjust for this just altitude as far as I know.

 Last time I dealt with this I replaced all the vacuum and fuel lines and
runner hoses and intake gaskets. I got the proper ones from Jim . After all
of this it still had the same idle running issue. The RPM would lag no load
unless I unplugged the IAD temp sensor. So I decided to adjust the MPS 1/4
turn CC richter until it ran smooth with the IAD sensor connected. It's been
fine since I did this. Now the idle issue has cropped up. I haven't started
it in 2 days to see if it's back to normal, hopefully it is. If not I need
to get it hot and either raise the idle 200 RPM or possibly adjust the MPS a
bit richer. The idle screw lock not is tight so it didn't change by itself.
I did install points and they only have 1,100 miles on them and while
driving I don't feel any difference in pickup and they still look new and
the gap hasn't changed.


 I also removed the engine lid and the lid seal was stuck to the lid so I
ordered it from ISP West.
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