On page 9 of the Bulletin No: 01-014/08, does anyone have the proper voltage readings when using SST N3M1-18-791 to obtain them?

 

What a lonely thread this is....

My friend Wayne has left Mazda, and he was my source for all info great and wide. That is why I asked the forum this question.

 

I think that they have a chart at Mazda Tech they use to tell if the vac reading is in spec...but they don't tell the dealer techs what it is.....

Most likely the techs figure out what numbers they need to use to get the engine replaced though

 

Yeah, I wish Wayne was still around. Now he is kneading peoples muscles instead of wrenching. Must be better money for him.

 

revival?

 

See if this helps:

 

Now we just need the "fail" level

 

Well, that chart needs to be extrapolated down (that is the response for the actual BARO sensor, same as the stock one, that is used for the test).
I think its pretty safe to say that the "fail" point would be about the same as the "fail" point indicated in the FSM, which is around 8 PSI net.
In other words, measured engine vacuum of less than 56 kPa or negative 6 PSI or so. I think that's about -12 inHg.

That said, I've had brand new motors read low for one reason or another, even when the compression was on-spec or better.
At my altitude, -7.5 PSI would be considered a "bad" motor, but its what mine reads with 130 PSI of compression.
It has something to do with the turbo system, no doubt.
Something in the air path alters the manifold vacuum. Probably some slight forward pressure from the turbo at idle.

 

Thanks - let me do the test now.

 

Dang - left the meter at the office... bloody hell

Ran another can of zoom zoom thru it last night - and blew out the cobwebs this morning - gotta say it is pulling hard again.

 

OK, I have my Fluke now, and will head home to do this test. Here is the chart extrapolated out.

 

Mileage 77,017
BARO Voltage 4.026
BARO Voltage @ Idle 1.828

So, I assume I take the differential of these two which would equate to 2.198 V. If that is true, my PSI at hot idle is 8.1

Correct me if I'm wrong about the differential, but it makes sense since the engine is an air pump.

 

I pulling 15.5" Hg on the LIM nipples and 15.5" Hg on the VFAD nipple also, and that equates to 52.49 kPa. That's down from 66 kPa at 70K mileage.