Need Help Setting Parameters for Speedo
Thread Starter
Teching In
Joined: May 2013
Posts: 23
Likes: 0
From: FM, Texas
Need Help Setting Parameters for Speedo I have a 69 Camaro that I have installed an LS3 GMPP crate motor with the GMPP E67 ECM and wire harness. I have also installed a Tremec Magnum 6 Speed. I called Tremec and they indicated that for my model transmission the VSS Pulse per Revolution is 12.0. I am using HPTuners to calibrate the ECM and under the Speedometer General tab, when I load 12.0 and change the VSS Tire Revs per Dist table to match the tires I get an exact speed match between HPTuners and the Garmin GPS I am using as a baseline.
HOWEVER, the speedo signal in the ECM is intermittent. It will work great for a mile or two then stop. I did some troubleshooting with the calibration and when I keep the stock calibration of 40.0 pulses per revolution the speedo signal is stable in the ECM but the speedo mph is way off as expected. Then when I make just the one change to 12.0 pulses per revolution for the new transmission, the speedo signal goes intermittent. What else do I need to change so that all the parameters are compatible with 12.0 PPR and get a stable speedo signal? Do I need to change some of the Err parameters also? To what?
Really appreciate your help. Thanks.
HOWEVER, the speedo signal in the ECM is intermittent. It will work great for a mile or two then stop. I did some troubleshooting with the calibration and when I keep the stock calibration of 40.0 pulses per revolution the speedo signal is stable in the ECM but the speedo mph is way off as expected. Then when I make just the one change to 12.0 pulses per revolution for the new transmission, the speedo signal goes intermittent. What else do I need to change so that all the parameters are compatible with 12.0 PPR and get a stable speedo signal? Do I need to change some of the Err parameters also? To what?
Really appreciate your help. Thanks.
TECH Resident
Joined: Aug 2003
Posts: 970
Likes: 4
From: England UK
Sounds like a very odd one.
I know when you say you set the ECM to read 40 pulses per rev, speedo is off, and when you set to 12 its intermittent. This would steer you to believe it something in the calculations inside the ECM. I wonder if its just a coincidence what the intermittent issue comes when you change the figure and its actually the sensor playing up.
I know not everyone has one, but I would be tempted to rig up an oscilloscope to the sensor output and get a passenger to check the waveform output when driving just to verify all looks good and the signal isn't intermittent.
Good luck.
I know when you say you set the ECM to read 40 pulses per rev, speedo is off, and when you set to 12 its intermittent. This would steer you to believe it something in the calculations inside the ECM. I wonder if its just a coincidence what the intermittent issue comes when you change the figure and its actually the sensor playing up.
I know not everyone has one, but I would be tempted to rig up an oscilloscope to the sensor output and get a passenger to check the waveform output when driving just to verify all looks good and the signal isn't intermittent.
Good luck.
Thread Starter
Teching In
Joined: May 2013
Posts: 23
Likes: 0
From: FM, Texas
I have done quite a bit of troubleshooting on this to confirm it is not a hardware, VSS, or wiring issue. I also changed ECM's and had the same issue so concluded it is an internal calculation issue within the software. This has to be a common issue for others using the latest GMPP E67 ECM so was hoping others would share how they "fixed" it.
So, just for curiosity, what happens if you change the pulse reading to say 20? Does it work for an extended time or does it cut out after a short while?
My thought was if you could get the pulse rate near your actual number, maybe you could adjust the tire rotation to get the MPH to work out correctly.
My thought was if you could get the pulse rate near your actual number, maybe you could adjust the tire rotation to get the MPH to work out correctly.
Thread Starter
Teching In
Joined: May 2013
Posts: 23
Likes: 0
From: FM, Texas
I tried a couple of different numbers with 20 one of them and it still went unstable. I did not try enough PPR's to see if there was a break over point where the calculation got stable. I was hoping someone would provide some guidance before I had to figure it out by T&E (trial and error)
Shoot me a PM with your email. I think I can help.
Btw, even though the software lets you change that 40 to 12, it doesn't affect the calculations.
Sounds like it just screws things up.....
Btw, even though the software lets you change that 40 to 12, it doesn't affect the calculations.
Sounds like it just screws things up.....
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Teching In
Joined: Sep 2015
Posts: 7
Likes: 0
Was there a solution to this problem??? I've been trying to work this out for months! Exactly the same issue but its happening with the stock pulse settings. I don't need it to read correctly but this p0507 is killing me.
Please help!
Alex
Please help!
Alex
