Just made a few (14) pulls yesterday and was reviewing some the runs when I notice something odd. There are two that have a strange curve in the beginning and I was just curious as to if this is where the converter is stalling/grabbing at (at least that is what I am thinking). Any thoughts would be appreciated.

Glitch in software. You cannot have more than one value at any given RPM. Throw away all data before 2400.

Did you do any other pulls?

Yeah, made a total of 14. Only two of them have this silly curve in them.

That looks to me like the optic tach was wigging out. I'd try to bring the tach pulse in on the ECM's tach wire for best stability.

John,

All runs were made with the tach signal from the ecm, not with the optical unit.

When you follow the curve around, it seems like the rpm is climbing, then slows down, and drops a 100 rpm or so then starts to climb again, almost like the starting off in the stall area of the converter. As rpm increases, the converter starts to grab the load and loads the engine down a bit.

No biggie, the rest of the run is fine, was just curious about it when I saw it.

Then I'd say that the ground clip lost contact. I've seen this before, and it has to do with the tach signal IIRC. I'll see if I can find my tests like that some day.

If you use Profilter, that will fix these runs I'm pretty sure.

Elowe, did you do any runs with the Juice/Predator stack, without propane? Curious as to what this stack does alone...
Thanks
Steve

Not that big of a deal, just was curious, nothing I could do about it now. Just thinking about next time on how to prevent it. We'll try Profilter next time. It was just strange that out of all the runs, only 2 of them had this.

Thanks.