308QV starting issue

The leak down test has nothing to do with fuel.(valve test I think)
I think that you need to have your fuel pressure tested. Could be weak fuel pump, dirty filter etc. Maybe even bad relay for the fuel pump.
My 85qv ALWAYS starts instantly. (takes just a little longer when hot)

 

Could be. There is also another relay involved in supplying +12V power to the fuel pump on your model so as an easy first step try some same PN relays from other positions in those two positions. The second relay has a name like "start valve relay" or "G-relay for start injector" and is the ...101 part number on the case (whereas, the fuel pump relay is labeled more clearly and is of the ...113 part number). Also gives you a chance to give the fuses/fuseblocks a quick visual (esp. left upper corner of left fusebox).

You should also learn how to unplug the safety switch so that you can run/check the fuel pump with the key "on", but the engine not running (the audible test), and when you're having an episode of "many crank attempt but no start", running the fuel pump beforehand via this method and then trying to start can give some additional clues. Try a search on "safety switch".

 

there exists a xener diode in a relay which pops-most typically from a voltage surge when "jumped"-this is an internal item in an aluminum can, in 3.2litre cars it is a GM blade relay found on top of a relay in the trunk(10amp as I recall)
If this "landslide" diode is gone-or-weak, the car will be difficult if not impossible to start.
also worth examing are the integity of the current paths on the mylar of the fuse pannel-a NOTORIOUS failure zone on 1980s cars-even on 288GTOs..
Lastly, the function of the cold start injector on old cars that "sit mostly" is not to be overlooked...
the hot re-start decay factor engineered in cis cars is NOT that sophisticated....
closed loop was a big deal, but that is really about it...
remeber that these cars still use thottle KNOBS for idle speed tweaking, and DO not have electically controlled Idle speed motors....this is 1984 and 1985!
CISe was in full implementation in USA market in 9-83 by MBNA....Porsche/AUDI NA

 

This is "normal" for your 308QV and is related to how the system of the safety switch and the two relays works -- i.e., if the airflow metering plate is not deflected (i.e., the safety switch contacts are "closed"), +12V power reaches the FP only with the key in pos III (start), not pos II (run). By unplugging the safety switch, this puts +12V power to close the fuel pump relay with the key in pos II, regardless of whether, or not, the airflow metering plate is deflected. Search...read threads... look at pictures...fix...

 

That's another possible flaw on a US version '84-'85 308QV (K-Jet with Lambda), but the symptom for that fault is a little different than you describe, and it usually doesn't "fix" itself (i.e., isn't so intermittent -- but that can happen). That flaw (no +12V power from the protection relay to run the FV/ECU because the 10A fuse on the protection relay is blown or the protection relay itself is kaputt) usually shows up as "low/rough idle, needing throttle blips to stay running, but quasi-runs at higher RPM". (Like the audible test for the fuel pump with the safety switch unplugged) You should learn how to feel/listen to the FV to confirm whether, or not, it's "buzzing" when the FP is running. It should always buzz, warm or cold, whenever the FP is running -- so do the unplug the safety switch/key "on" thing and feel the FV too.

 

No trouble -- but it isn't like this is the first time this subject has come up

Your model is fairly immune to jumping problems since it has the protection relay architecture -- which "protects" the injection ECU from an overvoltage condition (from your alternator or somebody else's altenator) via the Zener diode going into conduction and (intentionally) blowing the 10A fuse if an overvoltage is ever present. If your FV is not buzzing when it should be, then you'll need to go looking into the protection relay and/or fuse.