Friday, June 3, 2011

DIY EPM (Engine Position Module) Take 1

Took a few hours to get my EPM started today. Last night I spent the night testing the electronics (Stock CYP Sensor) and taking all of the measurements and making all of the required adjustments.

First thing was to move the bearing on the distributor shaft. It had to be pressed approximately 20mm further down onto the shaft. Pulley puller worked like a charm to more the bearing into place. This was done to keep the overall height of the EPM down. I took it as far as I could go without interfering with the CYP sensor.

This sensor will be used as the cam signal in the my two trigger COP setup. So it's really not an engine position module as much as it is a cam position module. The 360° 12 tooth crank pulley (24 tooth 720°) and stock CKP sensor are the other part to complete the EPM.

Now onto the cutting, grinding and filing. If I had access to a machine shop I still probably  wouldn't use it. I need to keep up the practice with the hand tools.

Stock P0B F22B2 distributor marked for cutting on the table saw.
Inside shot
Not a bad cut for a 12" 3/32 cut off blade on a cheap table saw. Biggest things was making sure the blade and deck and guide were all square. That took longer than the actual cutting. It only took 2 1/4 passes to get it cut through......5-10minutes tops, cut like a hot knife through butter!
Really didn't have to do much filing to get it level and flat
There was more filing involved after the coil deck was rounded off. It required a step down in order to have a proper sealing surface.
Then it was time to fit the filler piece for that step, just so happened to be just shy of a 1/4". So a cut, rounded and shaved scrap of 1/4" aluminum plate did the trick.
No fancy O-ring grooves so a roughed up surface and some Honda-bond will have to do. Once that was cut and ready to go it was on to cutting down the distributor shaft.
There was quite a bit to cut off. You can see the rest of it laying on the work bench in the background. Shaft and bearing rolls true with the bolts in.
Got the EPM cap, another piece of 1/4" scrap, rough cut and put into the vice for final fitting just before it was time to go. This scrap was going to be an IACV block off plate at one time.....This is a much better use for it!

Little UFI

The stock height of this distributor from the base with the cap, not including the plug boot stacks, was approx, 120-125mm. The total height of my EPM is 45mm. I probably could have gotten it down to 40-35mm but that's cutting it close for the stock sensor sitting inside.

Hope to have the cover and wiring done by the end of the weekend.


  1. wow! i love this. it is exactly what i was thinking for a build i'm doing. add 2 optical sensors and a plate with holes in it, or original toothed gear with a second single toothed gear and mag sensors. toothed gears i have, but an optical plate could easily be made on CAD and laser cut. depends on what sensors i can find to fit.

  2. In my travels I found a few different OEM sensors that are being used. Toyota I think was one. If I remember correctly there is a list of the Mag and Hall effect type sensors on one of the MegaSquirt web sites.