Testing Trigger Points

[Schroeter]

Starting a new thread, and quoting part of another one:

From Schroeter:
I've got good spark. Seems to want to start for 1 second, then no kicking. Then flooding. Bosch D-Jetronic system. W114 model. 1969 250ce.

I pulled 2 injectors out to watch the pulse, and it starts nice and short pulse, then about 1 second later, long/heavy pulse.

There was fuel in the throttle position sensor area, could this have damaged that sensor?

I was also wondering if the injector trigger contacts in the distributor may be mucked up from flooding?

Just looking for suggestions.

Best Regards,
Michael Schroeter.


From Graham:
"I doubt you could damage the TPS - It is on outside of throttle housing.

Trigger points are a possibility. I had this happening on my SL. The fiber cam followers had worn down and the points were staying closed for almost a full revolution. As a result, the injectors were firing at the wrong time and for too long. If you open the distributor up and look at the trigger cams, you can see how they work.

When I had a similar problem, I took the distributor out and tested it on the bench. If you connect an ohmmeter from the center contact to each of the others in turn, and rotate the distributor, each set of points should stay closed for about 110 deg or so. Or at least thats how my good points are. I wish I had had an oscilloscope or a scopemeter, but the ohmmeter did work.

If they don't test out, you may need a new set of trigger points. But they are VERY expensive. Used sets may be as bad as the problem ones unless they come out of a known to be good running car!

I have an idea on how we could adjust the trigger points. If you are interested, it might spur me to do it and take some pictures!"

From SChroeter:
"Hi Graham,
I'll start taking my distributor appart. I'll take pictures also.

I'm very interested in you idea on "adjusting trigger points".

I'm a bit new to this forum, but I'll try to start a new thread here in a moment.

Cheers,
Michael Schroeter "