LS3/480 and Cam Surge

Howard Jones

Isn't there a software reset for loss of throttle peddle signal that is meant to be reset at the dealer so as not to allow use of the car until a dealer qualified mechanic can check out the system for safety? I think someone had that issue with a drive by wire GM system here at some point. Worth asking.

Ken Roberts

I'm gonna guess and say it is a bad crimp. I would de-pin the connector at the throttle body and accel pedal and check the crimps. You can usually de-pin a connector with a large sewing needle.

Do the T body connector first due to it being easier to access.

Went to my third tuner and followed the suggestions from the site. We went richer and in lieu of a dyno tune, I requested a street tune. So we used an empty industrial area and focused on normal city speed driving (I was not focused on maximum HP). The car is 100% improved. To finish the tune, we will change out the 1.32 drop gear of the Graz and then complete the tune.

Interesting bit of information, at least I was not fully aware. We talk about the VSS signal a lot on the site. Many, self included, are using the Dakota Digital to send a VSS to the ECU. Tuner showed me a table where the ECU uses MPH to help it reduce throttle input when you want the motor to go to idle regardless of when you take your foot off the throttle. A no speed input to the ECU can/might cause stalling of the motor. So the ECU does need MPH, it does use it, and based on that speed it tempers the throttle adjust to reduce RPM to reach your desired idle RPM. It happens very quickly, so nothing you can hear.

Having said all that, what caught my interest is the DD system's speed reference is essentially linear. It works well, but there is an opportunity for a more robust speed signal to the ECU...aka via a relucter. Apparently the relucter is actually more dynamic in its signal to the ECU, again all at speeds beyond our hearing or seeing, but better than the DD linear feed.

Not being that smart about the correct teeth/sensor combo for the LS3, has anyone found the right combo to use for a mechanical speed reference to send to the ECU, no worries on speedo?
Andrew and Frank were both right about big cam tuning (not that the GM Hot Cam is big). It’s a bit counter intuitive.

I started reading more about Franks and Andrews insight following their responses......just wish I had been more knowledgeable sooner. Tunes are expensive.

Lesson learned, have some general understanding of the tuning process, make sure the tuner understands big cam dynamics, and make them pay more attention to low speed drive ability over just top end HP and torque.