Not the usual hot start problem...

[dr. no]

Starter spins just fine, not a starter issue.

With that out of the way...
Only when warmed up, and I mean warm, not even up to usual running temperature (needle just below the light), the engine will crank and crank and crank, and not catch, even if the engine is stopped just a second. As long as you leave it running it runs fine. Starting from cold is fine, catches on the first rotation. As it cools down it will reach a point where it will sputter and start if the throttle is held open.
There is nice blue-white spark;
The fuel pressure regulator holds 35 PSI at least for 10 minutes, and the pressure jumps to 40 as soon as the key is turned;
There is good gas flow as well as pressure;
Temp2 seems to have the correct warm and hot readings (there is no cold here);
changed the pump relay, no difference.

What next? I haven't checked the voltage at the injectors yet.
_________________
Scott
http://lungehphoto.com

'83.5 Westy s/p 1.6td JX and 4sp DK transplant--wonderful!
'86 MB 300GD
'06 MB Sprinter
'17 BMW X1
'89 Isuzu Trooper


PAST VWs:
'82 NA diesel Vanagon
'86 7-passenger Vanagon
'77 Bay
'71 Bay
'74 Things (2)
'69 Karmann Ghia (the only one I miss--in nice weather, anyway...)
'91 Fox

[MarkWard]

Is this on the 82 AC? When the engine is cold based on ambient temperature, the cold start valve or 5th injector sprays into the plenum while cranking. With just a little engine heat, the temp switch for the cold start valve turns this feature off. It could be this little extra fuel is all that is needed. Sort of like pumping the gas pedal on a carb car when you start it. The temp sensor also inrichens the mixture when cold or ambient temp. Sounds like you are not getting enough fuel. Have you tried pulling a spark plug after you have cranked it and it wont start? If you have a rich condition, the plug will appear damp or sooted assuming the ignition is not the problem.

VW came out with a hot start relay kit. It consisted of a relay and harness that tied into the starter and the cold start valve. Installed, while cranking, regardless of temperature the cold start valve would pulse. If you have carbon deposits on your intake valves and old injectors, this might be a solution to your problem
_________________
☮️

[dr. no]

I should be more specific since now I have too many. It's the '83.5. The '82 is a diesel (1.6 liter naturally aspirated).

It seems better now with the grounds cleaned (again). I'll post more if it keeps acting up.
_________________
Scott
http://lungehphoto.com

'83.5 Westy s/p 1.6td JX and 4sp DK transplant--wonderful!
'86 MB 300GD
'06 MB Sprinter
'17 BMW X1
'89 Isuzu Trooper


PAST VWs:
'82 NA diesel Vanagon
'86 7-passenger Vanagon
'77 Bay
'71 Bay
'74 Things (2)
'69 Karmann Ghia (the only one I miss--in nice weather, anyway...)
'91 Fox