trigger points question, double firing?? Options

[jeremiah98125]

I seem to have an issue with my injector trigger points on 72 1.7L. All 4 cylinders seem to be running a little rich which I think is another issue, but 2 of the diagonal ones (2+3) are super rich, they totally blacken the spark plugs within a few minutes. I pulled the distributer and cleaned up the trigger points with some contact cleaner and they looked fine to me. It seems from what I've read that they are double firing? What would cause this? Wondering what I should be looking for when I pull the distributor again, and how I can test them once removed? They have 60k miles on them, would a new set be worth the $$? thanks!

[Dave_Darling]

Randy W from the Roadglue site found a set of bouncing trigger points. He chased and chased a problem for a while and finally dug out a scope to check the trigger point signal. At least one pair was double-firing.

BTW, Cap'n... I believe the trigger points do fire diagonal pairs, not opposite ones. And I think D-jet only injects once per cycle; the L-jet injects twice per.

--DD

[Cap'n Krusty]

Randy W from the Roadglue site found a set of bouncing trigger points. He chased and chased a problem for a while and finally dug out a scope to check the trigger point signal. At least one pair was double-firing.

BTW, Cap'n... I believe the trigger points do fire diagonal pairs, not opposite ones. And I think D-jet only injects once per cycle; the L-jet injects twice per.

--DD

You're right, Dave, about the pairing. I was wrong about that. It's 1 & 4, 2 & 3. However, you're wrong about the number of pulses. Each injector fires twice per cycle.


The Cap'n