Inconsistant Stutterbox settings...any ideas?

[Scott Y]

Yesterday at Bandi I could not adjust the stutterbox. It's a keydiver chip, with TPS adjustment for the stutter rev limit. For several runs I was stuck at 4500rpm, then I was able to bump it up to 5000. I couldn't make it adjust at all after that. It took about 15 attempts to get the change to take. The clutch switch works, and the connections look like they did when it was installed over 2 years ago.
Logging shows that the TPS goes from 10.1 to 99.6. perhaps I just need to unwrap the connections and take a closer look.
I had an new EPROM burnt with some other modifications; as I remember the stutterbox worked fine on the old EPROM. Can an EPROM be flaky like that?

[Kibo]

It's unlikely the EPROM itself is flaky, although it could be some sort of issue with the way the code was written. Jeff is pretty competent, though, so that seems unlikely.

What kind of changes were made to the new EPROM, and who burnt it for you? It's possible there were some unintended consequences of the modifications that affected the stutterbox (unlikely, but possible).

The most likely culprit would normally be sensors, but it sounds like you've already verified that. Did you verify the clutch switch via datalogger (i.e. what the ECU is 'seeing')? I assume you're aware of the relatively common problem of the TB not being grounded once you remove the cast iron brace between the intake manifold and the TB (plus that little L-bracket that goes from the TB mounting bolt to the top of the TB).

I'd be happy to look at the EPROM for you if you'd like.

[Carl Morris]

I'm not sure, but Jeff's code may work like Todd's did, which was to use the idle switch rather than the TPS? If so you could be having problems with your connection to that switch.

[Kibo]

Oh yeah...forgot to mention that my whole grounding scheme line of questioning was centered around the idle switch. I don't really know how keydiver's adjustable stutterbox is set up to work, so I was ASSuming it was TMO-like. :p

[Scott Y]

The brace is still in place, as is the little L bracket. I'll look at the idle switch.

This was a reburn by Jeff, leaving existing options and adding the pump gas timing maps. I sent my old EPROM back, so I can't swap it to test.

Thanks for the ideas.