Magnetic & Hall-Effect Crank/Cam Sensor Setup

[doc]

Will do. Thanks for all the help Danny.

[UR50SLO]

We had a customer here with a '65 Mustang Fastback with a '03 Cobra engine with a Holley HP EFI. I helped him get the startup file, but always had a low RPM Sync error and would stall. Replaced cam/crank sensors with no luck. I found this thread. Now, on the first page, you had Modular engine ignition settings. I put those in (instead of picking the drop down Modular engine setting). The low RPM Sync error went away, and it runs fine now. THANK YOU for posting that. I was having a hard time figuring out what was going on till I tried your settings. Have a great weekend, Scott.

[Bullshark]

After much head scratching and frequent discussions with Holley, we finally got to the bottom of a problem I was having trying to upgrade from Version 2 to version 4 Dominator/HP EFI software. Version 4 is sensitive to the pulse width of the Hall-Effect pulse.

My Dart 541 cid engine with Holley Dominator ECU, Coil-On-Plug, saw tooth 60-2 crank trigger wheel, and FireStorm crank/cam sync distributor (used for cam sync only) ran perfectly when configured with Version 2 EFI software. When I upgraded to version 4, it would start, and then almost immediately die, loosing sync. I ran System Logs & Datalogs, sharing them with Holley Tech support, which showed no loss or anomaly of crank/cam pulse loss or timing variation. I tried numerous troubleshooting configurations i.e. HP ECU, multiple EFI software installations, rise & fall pulse trigger settings, etc. Holley could offer no explanation. It was only after finally changing the crank trigger wheel to the square tooth version that I was able to succeed. With my EE background & limited knowledge of the Holley ECU detailed design, I can only come to the conclusion that with the saw tooth wheel, I had a very narrow pulse when the Hall-Effect sensor picked up the ramp on the tooth vs the definitive fall. With the square tooth wheel there was a defined 50% duty cycle. Software execution timing in the Version 4 ECU must be sensitive to the narrow pulse? Anyway, heads up!

[sacarguy]

I'm confused. In the EFI software it designates cam sync to precede cylinder #1. Yet at your recommended 330° cam sync position on a 4 cylinder setup (I'm using with a Hall-Effect 1 Pulse/Fire crank sensor, and a 60° crank reference), that would put the cam sync happening 330°, which is 30° after the cylinder #4 crank pulse and prior to the cylinder #2 crank pulse (1342 Firing Order), which will happen at 180° before TDC + 60° crank reference angle, so approximately 240° BTDC #1 for the cylinder #2 crank pulse. So the cam sync would precede #2, not the #1. So do I change it in the EFI software under the Firing Order to 2134 to compensate or?

Oh, I'm using a Digital Falling Hall-Effect crank signal, 1 Pulse/Fire and a Digital Falling Hall-Effect cam sensor with my distributor. Rotor phased so that it's pointing directly dead center at #1 at my peak timing under load boost of approximately 24°, with all other timing events happening as described.

[Danny Cabral]

UPDATE: The new V4 EFI software allows the Ignition Reference Angle to be changed from −360° to +360° BTDC on #1
cylinder. This eliminates the requirement to alter the Firing Order in Ignition Parameters for some unusual applications.
http://www.masterenginetuner.com/top...all-fails.html (Crank Reference Angle Importance)

[metal tech]

I found that MSD makes a cam sync sensor for SBC/BBC that drives the oil pump and has no distributor type cap on it. With the elimination of the distributor cap, does this have the same signal quality that the Holley cam sync distributors have? I'm planning on using the 60-2 crank trigger & CNP coil setup, so the additional room saved by not having a cam sync the diameter of a regular distributor is appealing.

[Danny Cabral]

I found that MSD makes a cam sync sensor for SBC/BBC that drives the oil pump and has no distributor type cap on it.

Yes, that's called a cam sync unit.

With the elimination of the distributor cap, does this have the same signal quality that the Holley cam sync distributors have?

Yes, the Hall-Effect sensor/1x signal is compatible with Holley EFI. It even says so: LINK.

[viciousride]

I decided to swap over to the MSD cam sync plug (PN 85221), and when reading the installation instructions, it appears an additional advance is required? In their example, they use 10°.
Now, it does state to follow the EFI manufacturers instructions, so I just wanted to confirm I should follow the same procedures
as described in the first post, and disregard the MSD instructions for setting up the cam sync. Does this all seem correct?
60-2 wheel and Hall-Effect sensor setup on 10th tooth = 60° ignition reference angle (360/60 = 6, each tooth is essentially 10°):

Rotated counter-clockwise from TDC until reaching 180° BTDC and installed the cam sync plug:

[Danny Cabral]

Now, it does state to follow the EFI manufacturers instructions, so I just wanted to confirm I should follow the same procedures
as described in the first post, and disregard the MSD instructions for setting up the cam sync.

Yes, simply follow the Holley EFI crank & cam sensor setup instructions in post #1 of this thread.
http://forums.holley.com/showthread....m-Sensor-Setup (Crank & Cam Sensor Setup)

(The GM HEI & Ford TFI distributors are installed at 10° Ignition Reference Angle, but they're operating one crank revolution ahead, so they're retarding a lot. On a high RPM race engine, it's best to keep the amount of ignition retard (occurring from such an advanced reference angle) to a minimum, so it's not used on expensive race engines. Of course, timing accuracy is always better with a crank trigger. The ECU couldn't control the ignition timing with only 10°-15° of Ignition Reference Angle (unless it functions like the GM HEI & Ford TFI distributors). The Ignition Reference Angle needs to be at least 10° higher than the maximum amount of timing used in the Base Timing Table. The Ignition Reference Angle is in crankshaft degrees.)

[viciousride]

Thank you, Danny!