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Here's a pic of a prototype for my own homebrew solution for EFI RPM input. Sorry, got in a rush when installing the finished product and didn't get any pics. I have several thousand miles on it now and it's been flawless. The wheel and trigger are from late model Fords. It was mostly coincidence that it worked out that way, but they were the best fit. This method does require the end of the damper be machined back about .050 to keep pulley alignment the same due to the fact that the trigger wheel is thicker then the oil slinger. You'll still need a dizzy to run the oil pump at a minimum. And if you're doing sequential fuel injection and/or a non-wasted spark coil on plug ignition you'll need an electronic dizzy with 7 of the teeth cut off. The 1 tooth left is a TDC @#1 indicator.

My current system is an MS2 running a FAST Ez-EFI throttle body for fueling and ignition is with GM truck coils fired in wasted spark setup.

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Images (1)
  • 351C_Trigger_Wheel_-_Copy_(800x532)
quote:
Originally posted by 4V & Proud:
any more info on the source of the wheel?

can't see in the pic, does the wheel key to the crank w/o modification or did you have to work on it?



The trigger wheel is a Ford part# XW1Z12A227AC available on ebay for $12.85

It required a small amount of machining on the ID to slip onto the crank snout and I think I had to file the groove out a bit for the keyway. The fit on the keyway is not too critical as it is being pinched into place between the the damper and the crank sprocket. And the missing tooth can be indexed anywhere over a wide range of degrees, you just need to input its location into the software. Using the original location of the keyway, it ended up at 66 ATDC.....JP

The sensor is a Motorcraft DY1293, from late model mustangs and f150 trucks.
quote:
Originally posted by comp2:
I drew up and cut my own plate for the XDI. As a note, check out the red alternator wire. It was screwing with the trigger. I had to put a plate over it.


Nicely done on the install. I didn't know how dirty the old electrical systems were until I started on this EFI install. Had a gremlin that was real tough to sort out. Before the doing the trigger wheel I was still using an MSD system and taking the tach output to run the EFI. Energy from the 6AL spark box was bleeding over in the the tach signal, but the data logs for the rpm were perfectly clean, however the manifold pressure sensor(MAP) was all over the place. After several days of research and trial and error I ran a temporary tach wire that avoided coming close to any other ignition wires and problem fixed.

Properly grounded shielded wire on the crank trigger definitely helps too.
quote:
Originally posted by MustangJP:
quote:
Originally posted by comp2:
I drew up and cut my own plate for the XDI. As a note, check out the red alternator wire. It was screwing with the trigger. I had to put a plate over it.


Nicely done on the install. I didn't know how dirty the old electrical systems were until I started on this EFI install. Had a gremlin that was real tough to sort out. Before the doing the trigger wheel I was still using an MSD system and taking the tach output to run the EFI. Energy from the 6AL spark box was bleeding over in the the tach signal, but the data logs for the rpm were perfectly clean, however the manifold pressure sensor(MAP) was all over the place. After several days of research and trial and error I ran a temporary tach wire that avoided coming close to any other ignition wires and problem fixed.

Properly grounded shielded wire on the crank trigger definitely helps too.



That kind of stuff can be tricky to figure out. With the erratic firing I was getting I suspected the trigger wire. To figure it out I simply put a plate over the other wire and it acted normally. Then I fabricated a permanent plate. It is something to keep in mind with any trigger wire:

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