The top fuse of block is ent comp and it's not 12v but all the others are except the last one which says reactor and its 0v

 

You need to cut down on the abbreviations so you can articulate better what you are trying to say. You left out the word "fuse" out which makes all the difference. With that being said, this is getting more confusing by the post. The 30 amp EGI Comp fuse powers a White/Blue wire that runs to the Main relay. When the relay closes (does so w/key to on) the voltage on this White/Blue wire passes onto a Black/White wire. Now this wire travels to pin 3I at the ECU. You stated that this pin had 12 volts w/key to on, but you say it measures a few volts or so at the EGI Comp fuse. This does not make sense. Go back and measure pin 3I w/key to on, but disconnect the plug first and then take the voltage reading. And why would you ground a fuse to the battery as this makes no sense unless you didn't ground it but rather instead you actually used the positive terminal of the battery which would provide 12 volts to this particular fuse?

 

Pulling engine bay fuses out and connecting dvom on volt scale should all read 12v right

 

Disconnect the plug ...... Fuse or the plug on ecu

 

That's the way to measure whether the battery is powering the individual fuse space properly as the Black wire from the battery positive terminal is connected to the side of the fuse box closest to the battery. This connection powers all the fuses in this fuse box with battery voltage. A way to measure whether the voltage of the fuse is good is to measure the voltage of the wire leaving the fuse. For example, as previously stated, the White/Blue wire leaves the 30 amp EGI Comp fuse and this wire should read 12 volts. The Black/Green wire leaves the 40 amp EGI INJ fuse and it to should have 12 volts as well. The 30 amp "Retractor" fuse powers the White/Green wire below the fuse box and the Red wire is powered by the Head fuse. The Main fuse powers the Black cable on the trailing coil side of the fuse box (farthest side from the battery).

EDIT: The BTN fuse powers the White/Red wire with 12 volts.

 

Pin 3I is at the ECU so the "plug disconnected" is the smallest plug at the ECU.

 

I'll do that later gtg back to work but got 4.5 at egi comp fuse and 9.5v at 3i ........ With it connected. But 12v at battry ..... Weird I have battery that was working in my daily in Mazda now but idk its 5 years old so maybe its gone bad the v doesn't make sense theo 3i was 12 but now 9...... And I replaced all engine bay fuses now

 

If you have poor connections at the engine fuse box and so on that would affect the voltage read on a particular wire. Also, if there is resistance on a wire that will bring down the voltage. A faulty Main relay could also contribute to a low reading. As stated before, the Black wire running to the engine fuse box should supply 12 volts to all the fuses and measuring the voltage of this Black wire as it connects to the fuse box will tell you a lot. Then from there you measure the wires as stated previously as they leave the fuse box. Or you could disconnect the 4 wire plug at the Main relay and measure the constant voltage on the White/Blue wire as well as the Black/Green wire as it should read 12 volts. If it does then you know the fuse box is powered properly by the battery and these fuses (two of them) are good. Then you connect the plug back to the Main relay and w/key to on measure the voltage on the Black/Yellow wire and the Black/White wire in this same 4 wire plug. If you read 12 volts then everything is good just after the Main relay. KEEP THINGS SIMPLE!

And when you pull the fuse to measure voltage you place the Red meter terminal on the metal tang closest to the battery and the Black meter terminal to a suitable ground and that is how you read for the proper voltage.

 

All the wires u stated above measure battery voltage and the fuse eng comp 30amp measures 12v with key off and the black wire on relay box measures 12v

 

Edited:
All the fuses in the Engine fuse box are powered directly from the battery so they receive constant power 24/7 as long as the battery is good, thus the key position in the ignition is not a player (doesn't matter). Check the voltage on the wires coming out of the Main relay w/key to on and specifically just measure the voltage on the two wires mentioned already which would be the Black/Yellow wire and the Black/White wire. Do this by unplugging the White 2 wire plug to the leading coil to measure the B/Y wire w/key to on. Also, next to the leading coil is a plug connected to nothing which has three or four wires to it and measure the B/W wire w/key to on.The B/W wire runs to pin 3I of the ECU so if it's 12 volts at the plug then it should read the same at the ECU. When measuring the B/W wire at the ECU remove the small plug first then take the voltage reading. Doing this will tell you if the low voltage reading you got yesterday was caused by the ECU pulling down the voltage which it should not.

 

With and to and I think boost sensor ..... The one next to rf strut tower and bolted next to air box all in plugged I get 4.2 at the 5vref 2a

 

Got 12v at 3i and 4.2 at 2a with boost sensor afm and to unplugged

 

Does "to" mean TPS?

 

Ya my bad het I got 4.2 at ecu pin 2a and 4.9 at sensors disconnected I only habe 3 unplugged tps afm and boost sensor any others ....

 

On leading coil I got .29 on g/y and batery at b/y I'm thinking cas fried maybe both lol cause I do have a spare and tried hand turning enign

 

The wire at the leading coil I asked for you to measure was the Black/Yellow wire (B/Y) and not the G/Y wire.


When you say you got "4.9 volts at sensors disconnected" does this mean 4.9 volts at pin 2A with sensors disconnected or does this mean you got 4.9 volts at the Brown/White wire at the disconnected sensors?

 

I'll measure that other one later with connector u just mentioned. But i meant at ecu the 2a pin I got 4.2 and at the br/w at any of the connectors besides afm I got 4.9v I gotta strip tape / rubber off the afm to find br/w so i disnt do it

 

What I was asking was did the 4.2 volts at the ECU occur w/the sensors connected or disconnected. Did the 4.9 volts at the sensor Brown/White wire occur w/the sensor connected or disconnected.

 

Sorry 0.029

 

Again, what does this mean?

 

With them disconnected on both

 

Both what? You mean you disconnected the plug to the ECU and disconnected the plug to the sensors and then measured the voltage on the wire that was connected to nothing?

 

Have afm tps and boost in plugged now and I get 4.9 at the br/w on the connectors and 4.2 at pin 2a

 

Instead of answering questions you keep jumping around and responding with different information each and every time. You repeatedly change numbers without explaining what they are supposed to be describing and so on. I'm sorry, but I can't help you for it's just wigging me out.

 

K sorry busy day. Here's what I got tps,afm,boost sensor all un plugged. Ecu pin 2a with key on and ecu completely plugged in I got 4.2v. At the brn/w wire from any of those sensors unplugged gets 4.9v. So i am thinking cas, I did the cas testing with a spare plugged in and got no change on the green yellow wire,I spun spare cas plugged in by hand and it didn't go to 5v. It was .029v