Ram Jet 502 MEFI 4 Crank Position Sensor?

[Hog]

I'm looking at three options:
1. What's currently there. Small Cap HEI with 8 pin ignition module. Seems maybe this setup was for Marine applications?
2. What's supposed to be there. Coil on plug with a 24x crank position sensor. Maybe MEFI 4b?
3. What I can do instead. Use the original Black Box PCM (4x) or maybe upgrade to the '0411 PCM (24x).

I'm going to remove the crank position sensor and use a borescope to see what crank trigger is actually there.

dave w

I just talked to my marine guy and says that only the Marine engines use the CKP sensor, he also says that MEFI 1-5 uses the CKP sensor in marine apps.

What was throwing me off was the Ramjet 502 letters on the ECM itself. Is that an Arizona Speed and Marine website listed on the PCM? I cant read all of it.

From all the guys that have done 257kb blackbox PCM to 0411 PCM retrofits, I would have to suggest the 0411 swap with the L21 reluctor.

Yo u should be able to tell which reluctor is there from the CKP sensor, the 4x are a single wheel reading sensor while the 24x ues a double wheel reading sensor which is over $100. The 4zx sensor is about 1/2 that price. There are EFIConnection reluctors that allow you to run the less expensive 4x sensor.

Of course if you have the ability to recalibrate the MEFI without paying the $250, that's an option also.

peace
Hog

[dave w]

It appears this 502 has the 4x (low resolution) L31 / L29 crank trigger wheel, see attached pic below.

I'm thinking the "budget" option is to use the original "Black Box" PCM with a custom 502 flash, along with some modifications to the original L29 wiring harness.

Looks like I need to install a L31 / L29 distributor, coil, ignition module, and MAF.

I'll need to confirm the CKP pictured below will work with the "Black Box".

Is there another "budget" option available that can control both the 502 EFI and 4L80E Trans?

dave w

[mecanicman]

If it has the l31 crank reluctor why cant you use an 0411? there is a van l31/4l80 file in the repository that is 12212156 o/s I believe.

[dave w]

If it has the l31 crank reluctor why cant you use an 0411? there is a van l31/4l80 file in the repository that is 12212156 o/s I believe.

The '0411 is a good option! For the moment, the plan is to keep to a minimal budget. I'm sure once the "Black Box" has things running OK, upgrading to the '0411 will likely happen.

dave w

[Hog]

My marine guy got back to me and here is a 502 marine engine with part numbers and prices.
https://www.marineengine.com/parts/m...nd-front-cover

And the reluctor for the crank(#40) and the cam gear CMP sensor(#39). By the cam gear it looks like it is a 1x signal, in that case the CKP sensor will use a 24x reluctor.
https://www.marineengine.com/parts/m...k-and-camshaft






The CKP sensor you pictured since being used on a 4x reluctor, it will work with a Blackbox PCM.

peace
Hog

[dave w]

The truck is a 1996, not good news PCM wise. I've not looked lately, is there a tuning software available for the 1996 black box?

dave w

[LRT]

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