Q on injector signals

[sano86323]

I am pretty sure I have this right, but would like someone who is sure of it to confirm it... cause it aint happening.

1) the dist. G signal fires once in each rotation of the cam shaft.
2) each pair of injectors (1/3 tied together, 2/4 tied together) should fire twice for each rotation of the cam shaft.

both of these are right, right? What I am actually seeing is that the 1/3 pair fires once per cam rotation and the same with the 2/4 pair.... which would explain why there is a fuel delivery problem on our project car.

Thanks for the sanity check.

[sano86323]

Pretty convinced that this is bad behavior from the ECU. Traces of the G and NE signals look clean. Having a bit of trouble figuring out a failure mode that would take out both signals though... that gives me pause.

But the biggest problem is the fact that it clearly is running during crank and a bit afterwards. Checked and the injectors are behaving the same way during crank as during run (which they should not be)... so I am left with a doubt...

Maybe the injector duration is longer during start and this is causing it to try to run? I am pretty sure the duration is longer, but I dont think this would explain the behavior... very confused.

And buying an ECU.

[heyoldguy2002]

remember...we have old skool batch-fire fuel injection...dont go looking for sequential injection

hope it helps ...I know naught else.

[sano86323]

Interestingly, it looks like the G signal happens between the firing of 1(/3) and (1/)3 rather than at the transition from 1/3 to 2/4.... that seems odd to me.

The above is from the geometry of the dizzy and the fireing order.