[T3] Question about D jet idle issues 73 T3

[William J]

It has the proper intake gaskets that are bakelite and the fuel pressure is 
30 PSI. I rebuilt this engine myself in 97 . I did change to a pertronix ign 
back in 89 yet it ran fine.

 I used a 72 case and heads I had here and it was the same exact auto trans 
1600 as the 73 the case and heads down to the PCV breather were the same . 
However the stock pistons on both had the dished drop and the new set which 
were Mahle were flat top yet at that time it ran perfect. I did used the 
dist from the 72 and the vacuum advance from the 73 because the 72 auto dist 
looked in better shape yet even timed at 5 BTDC I didn't have these issues. 
I checked the timing and it does not jump around and is steady .

 The odd part about this is the car didn't have these issues in 2006 . In 
2009 I changed all the fuel lines and filter , spark plugs , vacuum lines , 
valve adjustment ext this is when it seemed to change . I didn;t touch the 
timing because without points it does not change. In 2015 May I replaced the 
plug wires with the same proper Bosch 7mm gray ones I had before. Did the 
valves again and still noticed this odd erractic miss and remembered the IAD 
temp sensor I unplugged in 2009 because it developed a hunting and would not 
start at times when warm and suddenly this all cleared up doing nothing on 
my part. At that time the idle raised as now with that sensor unplugged yet 
it seemed to run better in 2009 even with that sensor plugged in . I didn't 
notice the popping and never tried to run the RPM's up in park I really was 
not paying that much attention .I have only put 1500 miles on it since 2009 
to present and only noticed the erratic idle because one day I had the 
engine running and the tail gate locked after a trip to the store so I had 
to unlock it with another spare key I carry before pulling it in the garage 
, I usually unlock it after I leave a store . I may have been there in 2009 
and I didn't notice it. I thought it might be the spark plugs I put in in 
2009 yet I bought set sets one for the rebuilt engine in 97 and a second set 
for spares . They were Bosch plugs W8AC if I recall . I can't be certain now 
if they were resister plugs because I didn't pay any attention . Always got 
my parts from the same place back then all they dealt with were VW air 
cooled.

 I haven't replaced the runner hoses or head gaskets since 97 . I did clamp 
the runner hoses to IAD in 2009. I haven't been on the freeway since 06 
except once in 2015 and it seemed to run fine 80 mile round trip . This was 
before the new plug wires and cap and rotor and valve adjust I did in 2015 
in March.

William
----- Original Message ----- 
From: "Jim Adney" <jadney at VWType3.org>
To: <type3 at vwtype3.org>
Sent: Tuesday, January 26, 2016 3:21 PM
Subject: Re: [T3] Question about D jet idle issues 73 T3


> On 26 Jan 2016 at 14:53, William J wrote:
>
>> Has anyone run across issues with an unstable idle that clears up with
>> the IAD temp sensor is unplugged ? It only shows up when there is no
>> load auto trans in park engine warmed up . If I give it gas from 900
>> RPM idle speed and watch the tach for lack of a better term it seems
>> to stuggle until it reaches 2000 RPM.
>
> Any chance this engine was rebuilt using Beetle intake manifold
> gaskets rather than the correct Type 3 ones? Dual port Beetles used a
> metal gasket there, but FI type 3s have a special bakelite
> spacer/gasket that's about 4 mm thick. If the Beetle gaskets are used
> there, they don't seal; they leave a vacuum leak that leads to lean
> running.
>
> Another possibility would be insufficient fuel pressure. Have you
> checked it? Should be ~30 psi for a '73.
>
> -- 
> *******************************
> Jim Adney, jadney at vwtype3.org
> Madison, Wisconsin, USA
> *******************************
>
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