cranking gap detection scale - explanation

[Jeepster]

Hi All,

having my Jeep running great on wasted spark (Injection follows)
Only during start I have sometimes problems with unexpected missing tooth and firing into the Intake.
(This is always hammering my choke-plates into the carb-housing )

Cranking is between 110 - 130 revs. and a little bit uneven. Think this parameter can help me.

Please, can somebody explain how it works? Possible Numbers are 50%-150%! Don't know which direction would help me.

Michael

[przema72]

You have very low cranking rpm, typical motors have 200-300rpm

How do you have a crank primary trigger type ?

Share your log file for cranking ?

[Jeepster]

yes, cranking is low - but it's more a agricultural device than a car you use
(my introduction in "General")
Starter is 6 month old, Battery is 2 Days old.

I use a 36-1 trigger.

three cranking logs attached. The last one is the good one

Problem seems to be solved. I used the native advance (without vac) of the old distributor as "cranking advance (13 degree).

The last log was with 9 degree advance and it was fine. Think the first 1-3 sparks made cranking uneven with too much advance. With the old D.U.I. distri it starts running with the first spark and the first 2 or three teeth of the starter

was lucky and didn't do a further start... hoping thats usual now

Michael

[Paulo11]

How do you have set the "Cranking treshold" ? Because your ignition start raise from 200, after 300rpm. Maybe you have just too much ignition advance on very low rpm. You can try set the treshold to 400-500.

[Jeepster]

when ignition raises, engine starts running. my threshold is at 270.
Problems where before advance from table came to play.

But will try your hint tomorrow. At this time there is a carb on the engine..
...perhaps this weekend, when the new injectors arrive, I will try to complete with injection.

Think this will change the starting situation/problems too.

With the smaller cranking advance (now at 7 degree) it starts much better. Think my old 13 degree was to early for the low cranking rpm. combustion hits the piston sometimes back against the starter. especially with higher CLT.

[Jeepster]

Problem has gone

Jeep starts instantly with reduced cranking advance (6 degree)

next problem is coming up misfiring during part throttle after warm up perhaps coil failure... analyse it tomorrow