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Cam sensor success
https://www.slantsix.org/forum/viewtopic.php?t=65328
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Author:  dpstark2 [ Mon Sep 14, 2020 11:31 am ]
Post subject:  Cam sensor success

I have been running Megasquirt 3X on my Dart for a few years now with moderate success. But I had no end of trouble keeping a stable idle AFR. After a lot of fiddling, I ended up deciding that my cheap-o injectors just wouldn't support the low pulse width required with semi-sequential injection. I already had a crank trigger and individual coils. I had previously converted my 440 in my Charger full sequential, so I went the same route with the 225. I was able to adapt a 4.0L Jeep cam position sensor to the distributor location on my slant. I think it's from a '98 model year.

After a few weeks driving, everything seems to be fine. I was concerned about the gear wear on the cam and I will probably continue to inspect that periodically. Overall it has solved my idle issues and even seems to help fire it off quicker. I think this mostly due to retuning the VE table and having longer injector pulses. With the new data, it's pretty clear that the fuel injectors were not operating in their controlled range under semi-sequential. Full sequential has pulse widths back over 3ms and it's working fine.

It was pretty simple to make the sensor work. Didn't require any special tools or machining. If anyone is interested I'll try to get some pictures up.

Author:  Reed [ Mon Sep 14, 2020 3:40 pm ]
Post subject:  Re: Cam sensor success

Very interested! Pictures and instructions are always welcome.

Author:  Greg Ondayko [ Mon Sep 14, 2020 3:56 pm ]
Post subject:  Re: Cam sensor success

Quote:
Very interested! Pictures and instructions are always welcome.
Yes.

I second!


Good work!

Greg

Author:  Dart270 [ Tue Sep 15, 2020 1:57 am ]
Post subject:  Re: Cam sensor success

I would also be interested. I am looking to seq inject a couple of Slants and was going to use a modified stock elec dist. This might be nicer/easier.

Lou

Author:  DadTruck [ Tue Sep 15, 2020 2:20 am ]
Post subject:  Re: Cam sensor success

I too am interested, as Lou mentioned, a Lean Burn distributor with a reluctor that has 5 of the 6 points ground down can also be used as a cam position sensor.

Author:  SlantSixDan [ Tue Sep 15, 2020 11:00 am ]
Post subject:  Re: Cam sensor success

Fifth! Pics and specs and writeup, please!

Author:  ryandcovalt [ Tue Sep 15, 2020 7:52 pm ]
Post subject:  Re: Cam sensor success

I’m interested in seeing/reading more too.

Author:  Rick Covalt [ Wed Sep 16, 2020 5:25 am ]
Post subject:  Re: Cam sensor success

Will this affect my Webers? :D :D They are multi ports! :D

I am always interested in learning from the smart folks on here. I'm not even sure what sequential means? Direct port injection I suppose?

Author:  Greg Ondayko [ Wed Sep 16, 2020 6:18 am ]
Post subject:  Re: Cam sensor success

Quote:
Will this affect my Webers? :D :D They are multi ports! :D

I am always interested in learning from the smart folks on here. I'm not even sure what sequential means? Direct port injection I suppose?
Prolly Not.

Post about your webbers in the Engine or racing section..

unless they have been gutted and retrofitted with injectors... Hint hint...


Hmm..I don't know anyone who would do that!??


Greg

Author:  MadScientistMatt [ Wed Sep 16, 2020 7:07 am ]
Post subject:  Re: Cam sensor success

I'm very interested to see pictures too. I'd currently been pondering if I could get a cam sensor into my fuel pump block off plate.

Author:  Dart270 [ Wed Sep 16, 2020 7:30 am ]
Post subject:  Re: Cam sensor success

Gill says my weber/efi setup is at the coatings place and is almost done. I plan to put that on the 62 Valiant with port/sequential injection and MSpro. Crank trigger is ready and cam sensor is one of the last unusual things needed. Can't wait to see what the low end pulling and MPG is like with individual runner sequential EFI.

Lou

Author:  Greg Ondayko [ Wed Sep 16, 2020 8:56 am ]
Post subject:  Re: Cam sensor success

Quote:
I'm very interested to see pictures too. I'd currently been pondering if I could get a cam sensor into my fuel pump block off plate.

I cant see why Not. Even just Hand grinding the ol eccentric down could be helpful to do that.

Greg

Author:  dpstark2 [ Wed Sep 16, 2020 9:16 am ]
Post subject:  Re: Cam sensor success

I didn't anticipate so much interest. Before I continue, I do have a couple concerns with this setup. First that the cam and sensor gear, while they look ok, may not mesh entirely correctly and/or have wear issues. Second, that this this cam sensor shaft may or may not get enough oil. That being said, here is what I did.

I bought a Spectra Premium FD39.

https://www.amazon.com/Spectra-Premium- ... B001FL788K

I had previously used this on my Charger. The gear on this sensor is nearly identical in OD and tooth shape to the factory distributor sensor. It seemed close enough to work. The body of the sensor had an OD about 20-30 thousandths smaller than the factory distributor. I thought that might work too. I did install it in the block without the shaft and I couldn't feel any meaningful play in the fitment with factory distributor O-ring around the base.

The cam sensor shaft has a long shaft that engages like a B/RB motor distributor. I measured the length of a factor /6 distributor from the mounting flange (that adjustable plate) to the end of the gear teeth (not the tab that sticks out the bottom of the gear). This turned out to be right where the roll pin in the cam sensor gear was. I removed the gear and cut the shaft to length. It just happened that if I flipped the gear upside down and reinstalled it, the teeth of the gear ended up where they needed to be.

With the gear flipped, I drilled the shaft for a new roll pin. This was a little tricky. I had to flatten the shaft to get the drill press to hold steady. Even then, it walked a bit. I reinstalled the gear, and then cut the gear to the same length as the shaft with an angle grinder. I ended up squaring the gear off by hand in the belt sander. I also used a file to shape the end of each tooth and remove any burrs.

https://photos.app.goo.gl/eGU7oLyW1PKcmYHSA

https://photos.app.goo.gl/nqYkJCecP4K7sbFi9

With all that done, I reinstalled the gear and found my roll pin location was a bit tight. The original setup had .01"-.02" end play. I had none. So I sanded the top of the gear down to create some clearance. Clean, lube, reassemble... done. I used the adjustment plate at the bottom of a distributor to create a hold-down. I cut the big hole in half, folded over some tabs, and it worked fine. At this point I installed the sensor in the car and ran the motor to watch it spin, which it did. It didn't walk or make any weird noises.

https://photos.app.goo.gl/RnzxT3AqGdHCwsp47

The last step was wiring. Note that this sensor uses a 5V signal and 5V power. There is compatible Ford sensor (just the plastic cap on top) that accepts 12V if you need that. I had 5V available, so no big deal. I had to time the sensor to the motor, which is not that big of deal (except I guessed if #1 was on compression or not... I guessed right). Fired right up and showed full RPM sync.

Here's the connector. It's not cheap. I think there are cheaper options, but this one I was able to get good pics of and knew it would fit correctly. I found the pinout in Google search. I'll post it when I consult my notes. Unlike the rest, I did write this down in my notebook.

https://www.amazon.com/gp/product/B009I ... UTF8&psc=1

Hope it helps someone.

Author:  Greg Ondayko [ Wed Sep 16, 2020 9:24 am ]
Post subject:  Re: Cam sensor success

I thinks there will be many likes.

Good work.

Greg

Author:  dpstark2 [ Wed Sep 16, 2020 9:49 am ]
Post subject:  Re: Cam sensor success

I just hope it helps someone.

My root issue was the injectors I was using just didn't respond below about 1.5ms commanded pulse width. No matter what I did to my tables, the engine would be all over the place at idle. Sometimes really rich, sometimes really lean... making this change allowed me to run full sequential which cut the number of injections in half. Now pulse width is more like 3-4ms and it all works fine.

For the record, semi-sequential usually fires the injector and spark on every revolution - twice as many times as necessary. You do not need a cam sensor to do this. Crank position only. Downside is you have to inject half your fuel every revolution. In my case, this was making pulse widths too small to control. My type of injector is generally not recommended for use below 2ms. Full sequential only squirts fuel on the intake stroke - once per every two revolutions. You need cam phase to do this correctly.

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