Crank Position Sensor question.
Thread Starter
Teching In
Joined: Nov 2015
Posts: 25
Likes: 1
Crank Position Sensor question. I'm installing a Megasquirt MS3Pro on the LS3 in my RX-7.
I have a question concerning the Crank position sensor.
I'm currently running an LS1 99-up PCM, with the Cam position sensor in the front timing cover. This is a sensor for the LS3, and worked fine with the LS1 PCM.
Due to my motor having the 24X reluctor wheel, I must use the 24X CKP sensor.
This sensor is designed to work with a 12v reference, but the MS3Pro harness is wired for a 5v reference.
Also, the MS3Pro does not have a 12v reference output to change the sensor signal.
I don't want to use an unregulated 12v source because it could introduce electrical noise into the signal.
Does anyone know if the 24X CKP sensor will operate correctly with only a 5v supply?
Thanks,
David
I have a question concerning the Crank position sensor.
I'm currently running an LS1 99-up PCM, with the Cam position sensor in the front timing cover. This is a sensor for the LS3, and worked fine with the LS1 PCM.
Due to my motor having the 24X reluctor wheel, I must use the 24X CKP sensor.
This sensor is designed to work with a 12v reference, but the MS3Pro harness is wired for a 5v reference.
Also, the MS3Pro does not have a 12v reference output to change the sensor signal.
I don't want to use an unregulated 12v source because it could introduce electrical noise into the signal.
Does anyone know if the 24X CKP sensor will operate correctly with only a 5v supply?
Thanks,
David
Black CS Vss I have ALWAYS supplied the Black CS with MY ECU's five (5) volt supply.
The Data Sheet, Hall Sensor Differential, can be downloaded from Allegro.
This sheet states operation voltage.
I have told this to Matt/Ben, did you call DIY ?
Lance
The Data Sheet, Hall Sensor Differential, can be downloaded from Allegro.
This sheet states operation voltage.
I have told this to Matt/Ben, did you call DIY ?
Lance
The LS1 Crank/Cam sensors run off 12V. It's how the PCM reads them.
For the LS2+ PCMs (and I assume Megasquirt is using similar drivers to the newer PCMs), run 5V reference for the Crank/Cam. You can use the same sensors I believe, but the PCM drives them and reads them differently.
For the LS2+ PCMs (and I assume Megasquirt is using similar drivers to the newer PCMs), run 5V reference for the Crank/Cam. You can use the same sensors I believe, but the PCM drives them and reads them differently.
Falling Edge Trigger ALL aftermarket ECU's, my 882, "read" Falling Edge trigger.
This is done because "Rising Edge" trigger will CREATE a position error with the error becoming greater with RPM and Heat changes.
When you "scope" the 24xe one WILL FIND 24 evenly spaced, falling edge, signals.
The Allegro sensor will "see" rising edge signals as this is a differential Hall sensor.
I too would like to know more about the use of this signal, rising edge, by the early GM EMS.
MY GUESS, just another way to avoid patent infringement with No REAL WORK done.
Lance
This is done because "Rising Edge" trigger will CREATE a position error with the error becoming greater with RPM and Heat changes.
When you "scope" the 24xe one WILL FIND 24 evenly spaced, falling edge, signals.
The Allegro sensor will "see" rising edge signals as this is a differential Hall sensor.
I too would like to know more about the use of this signal, rising edge, by the early GM EMS.
MY GUESS, just another way to avoid patent infringement with No REAL WORK done.
Lance
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
Kinda surprised your Megasquirt doesn't have a regulated 12V output since they date back even further than the LS1.
If you decide your need a 12V source after all, you only need a #7812 12V regulator and a 100uF capacitor which will cost you a total of $3 at Radioshack.
EFIHARNESS: Are the pinouts on the 24x and 48x crank sensors the same? And the 1x and 4x cam sensors?
If you decide your need a 12V source after all, you only need a #7812 12V regulator and a 100uF capacitor which will cost you a total of $3 at Radioshack.
EFIHARNESS: Are the pinouts on the 24x and 48x crank sensors the same? And the 1x and 4x cam sensors?
Last edited by mrvedit; Nov 12, 2016 at 05:39 PM. Reason: Correct Microsquirt to Megasquirt
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 CAS sensor operation The CAS answer is INCORRECT.
The LS-1 "rear" sensor location (long sensor) has the same VCC, ground, signal as the CS in that same order as the CS sensor, just a different indexed connector.
The later LS-x "front" CAS sensor (short) location DOES have the reversed VCC as stated.
The "experts" SHOULD read the, any, Hall data sheet at the Allegro site.
I have never found a Hall sensor VCC that the VCC was not from 4-24 volts as specified in their Data Sheet. (AST-627)
Lance
The LS-1 "rear" sensor location (long sensor) has the same VCC, ground, signal as the CS in that same order as the CS sensor, just a different indexed connector.
The later LS-x "front" CAS sensor (short) location DOES have the reversed VCC as stated.
The "experts" SHOULD read the, any, Hall data sheet at the Allegro site.
I have never found a Hall sensor VCC that the VCC was not from 4-24 volts as specified in their Data Sheet. (AST-627)
Lance
Lone Star with Carroll Thanks, "Cobra" my first Cobra work was for the Ford "Lone Star" project.
I could send you a copy of my original quote "signed" by Len Bailey.
I have a customer, Nick@Rogue Racing, a Cobra Kit car with my Eight Stack 65mm ITB's
Would you like that picture ?
Lance
I could send you a copy of my original quote "signed" by Len Bailey.
I have a customer, Nick@Rogue Racing, a Cobra Kit car with my Eight Stack 65mm ITB's
Would you like that picture ?
Lance
Thread Starter
Teching In
Joined: Nov 2015
Posts: 25
Likes: 1
That's cool. I'd love to see the quote and pics.
I built my 427SC Cobra replica way back in 98-2000.
It has an original 1968 427 Sideoiler service block, with full forged crank and rods, and 12.5/1 Arias custom pistons, Ported and polished Edelbrock Aluminum heads, Custom grind Ultradyne cam, and much more. It's built basically to what NASCAR specs would have been in the late 60's.
I bought the LS swapped RX-7 because I wanted something essentially as fast, but with the comfort of A/C and a top. It also helps that the LS can run on pump gas.
I love the Cobra, but it requires a lot of compromises to actually drive it, not to mention it's a show-winning build, and for every hour I drive it I spend 10 hours detailing it back into shape.
I actually DRIVE the RX-7.
