Split Air and Port Air solenoids
 

i got these two engine codes when i was testing the ECU on my 89 GXL, and went to check the volts according to the FSM

for the split air, it says that the volts should be below 2.5 in 5th...however, according to the voltmeter, it read 0.020V....

and for the port air, at idle, the reading is at 0.080V, where it should be 2.5 as well.

now i havent yet got a chance to check the ECU for continuity, but what do you guys think about the values i got? i know it should be below 2.5, but thats alot lower than i think it should be

if anyone can provide me with some insight, it'd be greatly appreciated

If your reading the voltage at the ECU with your probe in the back of the connector, on the right wire, with the connector installed on the ECU, with the key to ON, then your ok.

Just to prove it, probe the Split Air Solenoids wire at the ECU with the connector still connected to the ECU. Turn the key to ON. You should see approx 12v. Now put the shifter in fifth gear. The voltage should have dropped to below 2.5 volts. Anything below 2.5 should be just fine and dandy.

If your NOT checking things out as described above.....please tell us your procedure and we'll give you our thoughts on your procedure.

And yes, I always see quite a bit less than 2.5 volts. I just don't remember any exact figure. Below is below...as in voltage drop below 2.5volts.

Ok, I will make sure to give that a try.

I found that reading it from the wire terminals themselves were not giving me accurate results, and kind of throwing me off with the values it was presenting me. I'll try what you described, and hopefully that might give me better results.

This is why they should not sell digital volt meters to the average guy- it just confuses the $hit out of most people. Seriously- what's the difference between 0 volts, and .020 volts, as far as our cars are concerned? Absolutely f-ing nothing...$10 meter from Radio Shack won't confuse you as much- why buy a $100 Fluke?

When Mazda says "below 2.5 volts", they mean zero, or de-energized. Unless you're dealing with a sensor input, in which case they'll give you a range...

I gotta love my cheap ass Radio Shack thing I borrow from my dad (uses it on his guitar).

I gotta look into buying one of those....

The digital voltmeter I was using had me clueless...

Your port air solenoid will stay at less than 2V... only used for the first 20K miles.

Just use a 19mm wrench and pop off the split air solenoid... and put 12V to it. If the rod moves, then it works, and you have a short/break in wire from the ECU to the solenoid.

Wayne is the fuckin MAN when it comes to emissions though.

[QUOTE=akademiks]I gotta look into buying one of those....

The digital voltmeter I was using had me clueless...



Lol, this is exactly what I'm talking about. I've used just about every meter known to man in my carrer- Simpsons, Flukes, meggers, time domain reflectometers, ultrasonic scopes, signal generators, you name it...I gotta train our new FCC-licensed avionics techs because THEY don't know what the hell the Fluke's trying to tell them. If you got one, and know how to use it properly, great. Know what I prefer to use on my car? You guessed it, a cheap $10 Radio Shack meter. It's all you need man...

Just an update...

Yesterday I was testing the Split Air and Port Air solenoids, and I found the continuity exists whenever I test the split air and port air wire terminals and their respective connections at the ECU. However, when doing the voltage tests (2.5 in 5th gear, and 2.5 @ idle) I do not get the correct readings. I believe for the port air, when it is in 5th, it is reading 13 volts, and the split air reading is well below 2.5 (#.000 range)

Anyone with some clue to what to next, please let me know.

It sounds like you did it right. The Port Air should read 12v approx all the time after twenty thousand miles. The Split Air Solenoid should read 12v in ANY GEAR BUT FIFTH GEAR. In fifth gear the voltage should have dropped to less than 2volts.

So turn the key to ON. Put the meter lead in the back of the Split Air Solenoid wire at the ECU and the negative lead of the meter on a good ground like the attach bolts for the ECU. The meter should read 12v approx when in any gear BUT fifth. Now put the car in fifth. The voltage should drop below 2.5 volts. Most likely less than a half volt. Anything below 2.5 is just fine. Just flop the shifter b/t fifth and any other gear and watch the voltage rise and fall to gain confidence in what your doing.

If you wanted to ohm the circuit out, you'd put the meters neg lead on a good ground like the ECU's attach bolts. Then the positive lead on the respective wire for the solenoid you want to ohm out WITH THE PLUG OF THE ECU DISCONNECTED. Both the Port Air and the Split Air should read approx the same. Meter on ohms. Key to OFF.

This is all very confusing to the layman, Hailers, but it's not our faults we keep getting this confused, it's the location that Mazda wants you to check voltage that's the problem. Most voltage checks are done BEFORE the component using the power, and that reading makes sense to all of us. However, in this case case (and several others in the FSM), we're checking voltage AFTER the component. In other words, when the ECU gives the circuit a ground (energizing the solenoid), we'll read 0 volts at the ECU pin, because the solenoid is dropping the voltage in a completed circuit. When we read 12v at the ECU, the circuit (and solenoid) is NOT energized, i.e. doesn't have a ground...

The port air solenoid at the ECU should read 12v after 20K because it isn't energized...Sounds paradoxal, doesn't it :)

If you're getting the correct voltages, there's no reason the check the circuit for resistances, you've verified a good circuit from the voltage checks...Cheers...

I have yet to get into the electrical troubleshooting on my car. I'm just trying to get other stuff fixed for now (just got a tranny in, vacuum leak, etc). Once I do all the mechanical stuff that I know needs fixed, I'll start checking all that electrical stuff.

Ok, truthfully, I'll get my friend to do that. He was an Aviation Electronic or something guy in the airforce. So.. time to whore him for work.

Ahh yes, aircraft electrician...I remember those days...If he doesn't have an FAA A&P license and Inspector certification though, he still can't hold a candle to yours truly. I'm really not this arrogant in real life guys, lol, just bringing up a little Air Force/ Navy rivalry from way back :) Don't start the flaming....

*****If you wanted to ohm the circuit out, you'd put the meters neg lead on a good ground like the ECU's attach bolts. Then the positive lead on the respective wire for the solenoid you want to ohm out WITH THE PLUG OF THE ECU DISCONNECTED. Both the Port Air and the Split Air should read approx the same. Meter on ohms. Key to OFF.******


Just sort of pretend I did not write that. Ignore, please.