broken93

According to all the information I have found, the ECU checks for opens on 15 of the 17 major solenoids. Jumpering these connections with a resistor allows the ECU to not detect an open across these solenoids, so it won't throw a code.

The actual resistance of the Mazda solenoids is 33 Ohms, but of course that requires about 5W of power dissipation per resistor. The alternative is to use 330 Ohm 1/2 W resistors, which dissipate 0.42 W each. The ECU doesn't seem to have a problem with this.

Since I've just bought a brand new wiring harness, I am going to go ahead and wire a weatherproof quick-disconnect plug to a resistor box to be mounted on the firewall, so I don't have to have resistors hanging off the harness. According to the wiring diagrams, all the solenoids share a common ground, so I should only need one ground bus wire.

The only questions I have are:

1) Is any of the above information verifiably incorrect, and
2) Which of these 17 solenoids are NOT tested by the ECU?

- Purge control
- Relief 2
- Split air bypass
- PRC
- Switch solenoid (?)
- EGR
- AWS
- ISC
- Turbo control #1
- Turbo control #2
- Charge relief
- Charge control
- Wastegate control
- Turbo pre-control
- Port air bypass
- Double Throttle control
- Relief solenoid valve

3) Did I leave any out? These are coming from the the FSM wiring diagrams.

broken93

hmm... I suppose my thread isn't good enough for the "advanced tech section"

J.S.J

The ECU grounds the solenoids most have different paths and terminals at the ECU (as I recall the turbo control 1 and 2 go to the same driver/terminal in the ECU), thus different grounds. You might have meant to say "power supply's" to the solenoids are common to each other. Mazda has a black wire with a red stripe powering the solenoids. I find that odd as orange or red would be more appropriate.

broken93

Hmm... according to the wiring diagram, the solenoids have a common wht/blk wire (GND). So are they switched power or switched ground, or is the white/blk a common +12V?

J.S.J

I don't have the manual in front of me but I did rewire all my solenoids and mount them on the fender-wells. The power (+) is on when ever the ignition is, the solenoids are grounded (NPN) via the ECU. As I said the wire colors are a bit odd. The ECU looks for conformation the circuit is open or closed depending on the programing. I even rewired my injector harness with a larger gage all the way on both ends. Almost always the "computer" will apply a ground to complete / activate the circuit. On some systems the "computer" will send positive voltage out to run the fuel pump relay. Other than that the sensor reference voltages normally come out as well but they are stepped down to 5 volts or so. The solenoids need to be controlled individually most of the time and since the spike from a ground is less powerful they use the ground. Scientific theory states current flows from negative to positive.

the_glass_man

iTrader: (2)

There are no resistors, there are no solenoids. This is the only truth.

J.S.J

Thanks for sharing

broken93

I did verify with a meter prior to putting my new harness in the car that all of the solenoids (all of the main rack solenoids) and most of the smaller solenoids that have a wht/blk ground wire all share common ground. To clarify, most of the wht/blk wires (not including the engine ground wires) that ground the solenoids are all bus-terminated somewhere in the harness.

J.S.J

First off the wire is ''BLACK with WHITE" There a big difference. The first color covers the majority of the wire and the second is normally a stripe or dash.
I know it doesn't sound like a big deal but surely there are white with black and that would be the incorrect circuit.

Second,
The "black with white is a "POWER'' wire NOT a ground. You must be interpreting something wrong.

broken93

Okay, let me clarify.

First of all, I stand corrected on nomenclature. They are black wires with a white stripe, so blk/wht.

Each solenoid in the main rack of eight solenoids has two wires. A small diameter switched wire and a common blk/wht. Apparently the blk/wht are a common +12V, not common GND as I originally thought. Switched ground is apparently the smaller gauge wire.

The point of this thread for me has pretty much disappeared as I decided not to hack the harness anyway.

MrRx

iTrader: (1)

I thought you were going motec, Your not going to try to run your twin set up on the stock ECU are you?

dubulup

I was just thinking the same thing?!?!?! why spend all this effort and use something as a 10 year old ECU...so many bugs and twitches in the technology of the past (for one the whole fuel pump wiring...speed relay, pump relay, and resistor what a joke pumps these days can run on 12V constantly and work fine for years). At least go PFC so you can cut the damn plugs out. I must have misread your other post about the harness, I thought you modified to look clean, why put all those un-needed parts under your hood????????????????????? WHY!!

broken93

Hell, no.

I was going to get the thing to start and idle on the stock ECU until I drop the $$$ on a microtech or AEM, or even a PFC.

I changed my mind and decided to not even worry about starting it on the ECU at all; but I haven't decided which standalone to use yet. The harness is uncut.

dubulup

I started my first rebuild on an E6X with a very custom wiring harness, and a DIY single. Wasn't bad and everything seems to be working great 2300 miles later. couple pics...
https://www.rx7club.com/showthread.p...light=electron

Does the microtech and AEM, use the stock ecu plugs?

broken93

Yeah, I remember seeing your thread.

The AEM uses the stock plugs natively. I have a good bit of experience with the AEM software, and I'm running premix, so I'm leaning in this direction.

The microtech is available with a jumper harness to use the stock plugs.

RotaSpinna69

iTrader: (10)

So which ones dont get resistors? Was your question answered and I failed to see it? What is the "Switch Solenoid"?

Thanks,

Andrew

Rotarytard

bump. I just converted non sequential and put resistors in all female plugs but i'm getting some codes. I've searched most of it but the threads doesn't give the answers i'm looking for. As in which solenoid/connector for each of the code and should they be resisted or not. I have removed all solenoids on the rack, removed air pump, acv, egr, and kept my purge control.

These are the following codes:
13 - Pressure Sensor
30 - Split Air
33 - Port Air
39 - Relief 2
45 - Charge Control
50 - Double Throttle
54 - Air Pump

Any help would be great. Thanks in advance
edit:: I also played around with the resistors by taking it out and resetting the ecu to see if there were any changes. This is killing me, I finally got my car started after the winter and I run into this. I tried driving it but I think it's in limp mode because I can't boost past 0 psi. It'll buck and backfire if i try to go past it.

J.S.J

The pressure sensor does not use a resistor
Relief 2, Charge Control, Double Throttle need resistors.

Split Air, Port Air are devices that were located in the upper intake manifold have different style plugs. They need resistors as well.
The air pump is controlled by the ecu but it uses a relay, so you may not need place anything where the pump plugged in. Just make sure the relay is turning on at idle and off at about 3k or so. I sold my car and my manual so I am working in the blind.