Has anyone had experience with this? Found one in a pile of stuff with no connector and just wondering about a wiring diagram, or even if it worth pursuing.

 

I've never even heard of a JR-branded AFM. Pictures?

Should be easy enough to figure out the wiring if you can get the cover off and inspect the innards.

 

I'll post a picture, but the inside is all potted.

 

I'll post a picture, but the inside is all potted.

 

Ah; the Air-Fuel Module. Thought you meant Airflow Meter. That thing was part of a JR boost upgrade kit. I honestly don't know much about it, but it obviously works on MAP.

Chris Swearingen has some experience with that box from way back when, so you might contact him about it. He had a lot of problems with it. Here's a link: http://forum.miata.net/vb/showthread.php?t=190228

Here's the JR document that details its installation: http://www.supercharger.com/graphics...ns/999-350.pdf

From what I can gather from their documentation, it goes in series with the stock airflow meter, and modifies the airflow signal as well as the IAT signal.


Seems pretty damn useless.

 

Thanks Joe. Does seem pretty useless. I was hoping it was an AFM REPLACEMENT. Guess that's why it was in the junk box.

 

Nope. To replace the AFM, you need both MAP and RPM. The second link in my sig details how to do this with an EMU.

Even at that, it seems that there are slight variances with both temperature and barometric pressure. Since I lived in San Diego the whole time I ran that system, it was not a significant problem. When others started copying it, they found that some re-scaling of the table was necessary to compensate for local prevailing conditions. Chris, in particular, noted a large degree of error when running my tables at his elevation in Colorado.

I guess the big question is- how do we finally talk you into giving up your EMB and installing a MegaSquirt?

 

That's the same MAP sensor used in the Megasquirt.

 

It does kinda look like the Freescale MPX4250AP, only on that sensor, the atmospheric vent is simply a tiny hole on the bottom of the part.

I can't quite figure out if that second hose (the one that terminates inside the case) is the atmo vent that's somehow attached to the bottom of the sensor, or have they stacked two sensors atop one another, and used the bottom one for barometric measurement??

 

that box looks like is it made by Split second.

 

I was trying to figure that out too...judging the plane of the circuit board, to me it looks like that vacuum line terminates just before the MAP sensor....but I dunno, it just looks really close to the 4250A...that's all.

 

Maybe the second hose is going to a bottom vent on the map sensor so they could pot it.

 

blow into the first and see