tI found a possible root cause for the idling issue : one leg of the intake spider was not tightened with the 2 bolts to the head. So air escaped.
After tightening and with my idle screw turned out about 3 turns CCW , idling is 950 rpm with AT in P. When shifting to R or D, idle goes to 800 rpm.
Much better.

Now I need to recheck the coldstart in the coming days whether engine starts directly without touching the gas pedal.

​​​​​​….to be continued

 

today I did a check again :
- still not starting cold. Only when applying gaspedal to the floor it finally starts
​​​​​​- idling during warming up is going to 1800rpm ! Even with turning idle screw CW till it almost is fully turned in, idle is still 1400 rpm
- when engine is warmed up, my idle is still 1100 rpm ( AT in P) with idle screw completely turned in…

However I did made some other discoveries :
- vacuum is quite high : 700 mmHg( - 0,7 bar) while it should be around 550 ( -0,55 bar)
- when reversing the tubes on my ignition distributor, engine runs much smoother and I can see vacuum go to around 500mmHg (-0,5 bar)
Also my idling is better : 800 rpm with AT in P and 750 rpm with AT in D, and idle screw is turned CCW 3 turns.
Could this be the real issue of my starting and idle problems?

 

Reversing the vacuum advance and retard lines on the distributor could cause the Idle issues, but doubt it would cause the cold start issue as the engine isn't really making any vacuum until it's running.

On a single vacuum port distributor, the vacuum advance port is on the front and there is no vacuum retard port. On a distributor that has both, the vacuum advance port is on the back and the vacuum retard port is on the front.

An elevated idle will increase vacuum so the 1,800.rpm idle could be why the vacuum you're seeing is also high.

 

Pull the center plenum and make sure that the throttle blade is properly closing. I just had an L-jet with a high idle. The stop screw was screwed in too far holding the throttle blade open.

 

Indeed, my idle issue is solved, but when trying to start the car again after 5 hours, the start did not go well and again I needed to
start the car again with gaspedal to the floor.😔
I measured the resistance of my thermo time sensor (35° 8sec):
cold : 35 - 0 - 35 Ohm. (G to ground - W to ground - G to W)
warm: 67 - 140 - 67 Ohm (G to ground - W to ground - G to W)

So this seems to be correct

Next test will be the voltage to the coldstart injector.
Any idea what voltage this at least should be?

note : I measured my timing again and it was 15° btdc @ idle , so within range

 

12v only when starter cranking I believe. Measure using the two contacts in the connector as it's the temp sensor that closes the ground side. If you don't get 12v when the engine is cold using the contacts, then try a reading using the hot wire and a different ground and see if you then get it when cranking. If so, it tells you the issue is with the grounding circuit via the temp sensor or the wiring to or from it.

The plug on the AAV should show 12v across the contacts whenever the ignition is on

 

So I measured the voltage on the blue coldstart plug : during cranking I got 8,5 V and once engine was started, it dropped to 0

When measuring voltage at the AAV plug, I did not get any voltage during ignition on
Here is a picture of the AAV just before coldstart :


Same for the brown plug to the thermo time sensor : no voltage ( this was measured 5 minutes after first start and thus with resistance 35 - 0 - 35)

 

won't be any voltage at the thermotime sensor as it doesn't have a power lead and is just a ground loop. When the switch is open (engine warm) the contacts inside don't complete the ground, but when thre engine is cold, they do and that's what causes the cold start injector to fire.

 

Is 8,5V sufficient to operate the coldstart injector? And how long does it spray, only during cranking?

 

I'm actually not sure and my K-Jet car is up on the lift because it needs torque tube work. I may be able to see what mine does on Thursday of this week when I need to move it to get the 84 Euro ready for SITM the next day (oil change and top up ATF) if you don't have it sorted before then.

 

no problem my friend. Keep me posted, I am curious about the result.
Normally the voltage comes directly from the starter and should be 12V:

 

I again verified the thermo time sensor and it is working as it should be according to the following schemes I have calculated :

COLD START VALUES

WARM START VALUES

But could the culprit be the start relay ???? SInce this is linked with the starter and should provide 12V , not ?

 

Good news : a new starter relay made the difference: car is starting directly. I only need to tune the idle during cold start ( 900 rpm is a bit too low)

 

What does it idle at when hot? If that's good, the elevated cold idle is managed by the WUR and AAV.

 

Sorry for late reply but after some tuning and testing, the idle seems to be OK cold and hot. I tuned the idle screw CCW.
Idling cold = 1100 rpm
Idling hot = 800 rpm

But the intermittent cold start issue is not solved
Yesterday I coldstarted the car and it fired up right away (engine was boosted during 1 second with extra fuel from coldstart injector )
Today I again tested coldstart of engine and now I need to push gaspedal to the floor to start it because I did not encounter any extra fuel injection from the coldstart injector...

So this means that sometimes the cold start injector is engaged.
Perhaps 2 possible causes ? :
- bad electrical circuit/connection (corrosion ..)
- bad working Thermotime sensor.....although I think that this sensor works or doesn't work at all

Any ideas ???