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Camshaft Position Sensor

Posted: June 5th, 2015, 7:59 pm
by CaffeineTripp
I'm sure this has been beaten to death since it's such a common failure, but I would like to try something new.

Since we bought the tan MX-3 with the B6 SOHC in it the CEL has been illuminated, and brightly at that, with the code being G-Signal. We all know this a little too well that the CPS tends to go out in the distributor and the only way to fix the issue is to replace the distributor entirely with either a remanufactured unit ($230), a junkyard unit which has no guarantee to work ($75), or you can purchase the CPS from across the pond for $70 (Part Number *J821) or attempt to find a Miata's (1.6)/Protege's (1.8) (Part Number *J825).

* The different between these two is minimal. The Miata's CPS should fit just fine, but I've yet to try.

The Miata's CPS
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The MX-3's CPS
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As you can see, the mounting holes and magnetic pickups are the same, the only difference is near the plug; the MX-3's somewhat slides into the distributor whereas the Miata's doesn't, it screws down with a plate. But these should be interchangeable.

In any case, the Miata's CPS is much like the DIS on the 4G63 engines; essentially a distributor connected to the camshaft but without the cap, rotor, and plug wires. It could be possible to use the same CPS system on the Miata's engine, and change the distributor system to a DIS by using the same coil pack.

It would seem to require the MSD ignition control system no matter what, but I believe that there would be potential.

Removing the CPS is easy as well.

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There's nothing more than taking a few screws off and there you have it. It easily slides out.

Heck, it might be even possible just to swap over to the Protege's distributor system entirely since it's a bit cheaper.

So, thoughts?

Re: Camshaft Position Sensor

Posted: June 8th, 2015, 4:20 pm
by Daninski
I have no clue abut the B6 I do know the CPS was used in the 92-93 GS then in 94 I beleive it was discontinued. My point is can you not use a newer ECU that does not need the CPS???

Re: Camshaft Position Sensor

Posted: June 8th, 2015, 6:52 pm
by CaffeineTripp
I'm sure I could, but I think sourcing a newer ECU and having to do any other large wiring, sensor changing, etc., might be a little more than the vehicle is worth. The DD has really gone down hill. I've got a used distributor coming which is free, so I can use that until I figure something out a little more permanent.

Re: Camshaft Position Sensor

Posted: August 29th, 2015, 9:54 pm
by CaffeineTripp
An update on the difference between both distributors disassembled.

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Here is with the distributor cap and rotor removed, along with the dust cap to show the top portion of the camshaft position sensors. USDM (magnetic pickup) on left, EDM (optical) on right.

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Further removal.

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Completely disassembled EDM distributor. You can also see how some of the casting is different.

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Completely disassembled USDM distributor.