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Re:03 Ford E350 dead misfire off idle (waveforms attached)

  • Ben
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4 years 2 months ago #50653 by Ben
I've got a e350 van here I'm trying to avoid going in cylinder I believe I have a dead injector in cylinder #2 it flags p0302 power balance screams #2 but it does not smell like raw gas at all (someday I'll get a 5 gas analyzer) but looking at the exhaust waveform I think I can see a leaking exhaust valve anybody else see it? These are taken during power brake in bay every 20 some screens look just like this 1 (its not jumping all over) ignition sync is on #2 primary ignition red Also no firing line at all on #2 at idle it looks fairly normal.though i find it hard to read the triple strike ignition.. the last 1 is a snap throttle this is the worst looking 1 i found in the snap.

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4 years 2 months ago #50654 by Chad
It looks, to me, like this exhaust waveform indicates a misfire on Cylinder #1. And, I would say compression on #1 is leaking into the exhaust. But, I am used to looking at an idle exhaust waveform.

 

I think I remember hearing, from somewhere, that raised RPM's will cause the waveform to shift. I haven't experimented with this. I'm interested to see what others have to say about it.

Can you catch the misfire at Idle?

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"Understanding a question is half an answer."

I have learned more by being wrong, than I have by being right. :-)

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4 years 2 months ago #50655 by Ben
It's hit and miss at idle I will get a shot of it at idle in a few mins

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4 years 2 months ago #50657 by Ben
Pulse sensor trace is inverted in this capture (positive voltage is negative pressure) sorry I forgot to fix that in this capture it is correct in the first capture

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4 years 2 months ago - 4 years 2 months ago #50667 by Chad
It appears that the waveform HAS shifted. Interesting.

"Knowledge is a weapon. Arm yourself, well, before going to do battle."
"Understanding a question is half an answer."

I have learned more by being wrong, than I have by being right. :-)
Last edit: 4 years 2 months ago by Chad.

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