The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > General Truck Forums > Engine & Drivetrain > LSx Swaps

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 07-20-2018, 08:34 AM   #1
solidaxel
Registered User
 
solidaxel's Avatar
 
Join Date: Dec 2002
Location: Cactus Patch So. Az
Posts: 4,749
Aftermarket Electric Speedometer

For those of you that have added a speedometer controlled by your ECM

What brand of speedo are you using ?
What is the signal that is produced by the ECM?
Does the transmission VSS make a difference if it is a 4L60E or a 4L80E
or is the "magic" controlled by the ECM and not the VSS?
What Pin or Pins control the speedometer and what is the signal that is transmitted to the speedometer?
__________________
53 TuTone Extended Cab 350 4-Spd 3:08 (SOLD)
53 Chevy Moldy pearl green ZZ-4 4L60E 9" 3:25
55 GMC 1st Black Mll (ZZ4) ZZ6 TKO 600 5 sp 3:73
62 Solidaxle Corvette Roman Red (327
340hp 4spd 3:36) C4 & C5 suspension tube chassis
LS 3 4L70E
65 Corvette Coupe 327 350hp 4spd 4:11
78 Black Silverado SWB (350/350) 5.3 & 4L60E 3:42
2000 S-Type 3.0 (wife cruiser)
2003 GMC SCSB 5.3 4L60E 3:42
solidaxel is offline   Reply With Quote
Old 07-20-2018, 12:59 PM   #2
dayj1
Senior Member
 
Join Date: Jul 2009
Location: Athens, AL
Posts: 499
Re: Aftermarket Electric Speedometer

Quote:
Originally Posted by solidaxel View Post
For those of you that have added a speedometer controlled by your ECM

What brand of speedo are you using ?
What is the signal that is produced by the ECM?
Does the transmission VSS make a difference if it is a 4L60E or a 4L80E
or is the "magic" controlled by the ECM and not the VSS?
What Pin or Pins control the speedometer and what is the signal that is transmitted to the speedometer?
I'm going to assume we're talking about Gen 3 PCMs since that seems to be what most folks are using.

The PCM outputs a square wave with an amplitude of 12V and a frequency that varies with vehicle speed on pin 50 of the red or green connector (depending on whether you have a "red/blue" or "/blue/green" PCM).

The VSS output defaults to 4000 pulses per mile (4K ppm), but can be changed in the tune.

4l60 and 4l80 both have 40 tooth reluctors on the trans output shaft and the VSS sensor reading the teeth on that reluctor wheel outputs an AC sine wave that increases in both frequency and amplitude with speed.

Most speedometers are going to want the square wave from the PCM and not the sine wave directly from the VSS.
dayj1 is offline   Reply With Quote
Old 07-20-2018, 06:26 PM   #3
solidaxel
Registered User
 
solidaxel's Avatar
 
Join Date: Dec 2002
Location: Cactus Patch So. Az
Posts: 4,749
Re: Aftermarket Electric Speedometer

I have a combination of a 2003 4l60E and a late model LS3

Thanks with that info I think I can answer his questions


I don't have the ECM in front of me but is a new ECM and the engine runs and the trans shifts, working on the dash speedo and Tach next
I can get an electric conversion for the tach but I can only use the stock speedo "Face"
which has a 180* sweep
__________________
53 TuTone Extended Cab 350 4-Spd 3:08 (SOLD)
53 Chevy Moldy pearl green ZZ-4 4L60E 9" 3:25
55 GMC 1st Black Mll (ZZ4) ZZ6 TKO 600 5 sp 3:73
62 Solidaxle Corvette Roman Red (327
340hp 4spd 3:36) C4 & C5 suspension tube chassis
LS 3 4L70E
65 Corvette Coupe 327 350hp 4spd 4:11
78 Black Silverado SWB (350/350) 5.3 & 4L60E 3:42
2000 S-Type 3.0 (wife cruiser)
2003 GMC SCSB 5.3 4L60E 3:42
solidaxel is offline   Reply With Quote
Old 08-06-2018, 12:43 PM   #4
solidaxel
Registered User
 
solidaxel's Avatar
 
Join Date: Dec 2002
Location: Cactus Patch So. Az
Posts: 4,749
Re: Aftermarket Electric Speedometer

Will there be a description on the aftermarket speedo to indicate what signal it needs to make it read MPH
__________________
53 TuTone Extended Cab 350 4-Spd 3:08 (SOLD)
53 Chevy Moldy pearl green ZZ-4 4L60E 9" 3:25
55 GMC 1st Black Mll (ZZ4) ZZ6 TKO 600 5 sp 3:73
62 Solidaxle Corvette Roman Red (327
340hp 4spd 3:36) C4 & C5 suspension tube chassis
LS 3 4L70E
65 Corvette Coupe 327 350hp 4spd 4:11
78 Black Silverado SWB (350/350) 5.3 & 4L60E 3:42
2000 S-Type 3.0 (wife cruiser)
2003 GMC SCSB 5.3 4L60E 3:42
solidaxel is offline   Reply With Quote
Old 08-06-2018, 06:40 PM   #5
Clyde65
1965 Chevy C10, 2005 4.8L/4l60
 
Clyde65's Avatar
 
Join Date: Aug 2004
Location: DFW Texas
Posts: 8,539
Re: Aftermarket Electric Speedometer

I used a Dolphin electronic, 8k was the setting I believe.
__________________
Clyde65

Rebuild of Clyde
http://67-72chevytrucks.com/vboard/s...84#post8338184

69 Aristocrat Lo Liner build
http://67-72chevytrucks.com/vboard/s...84#post7561684



support our troops!
Clyde65 is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 11:00 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com