Sesshoumaru

iTrader: (1)

after trouble shooting my sensor and found it had a dead spot i decided to hard wire the ecu to 5th gear.

I was wondering about the side effects. This is what i could come up with

No shift up light
Possibly no reverse light (haven't checked yet)
timming advanced and fuel reduced in other gears than 5th under light load

any other reasons this is a bad thing?

Icemark

Yeah, it leaves the air pump on full feed through the ACV to the cat

WAYNE88N/A

Hey Mark, have you read the thing me & Hailers were discussing about that split air solenoid? Can't remember the post title now, but I could find it...If you read it, what do you think about the book tests being totally ***-backward from what most guys believe?

Icemark

remind me of the link/thread

WAYNE88N/A

"5th blows engine fuse", page 3...

WAYNE88N/A

darn, first time I've double posted in a long time

Icemark

You don't understand how it works. hailers is right, and the book is right... you are not understanding how it works.

Sesshoumaru

iTrader: (1)

good point- but i dont' have a pump anymore.......

just wondering if i need to un-f@#k it or not.

So far i have experience no side effects. Only better gas milage

Icemark

well it does lean the mixture slightly in 5th, and rumor is that it also changes timing.

I don't get why you just don't fix the car

Kenteth

Hey guys.

I did the auto/5spd swap. I don't remember even wiring the 5th gear switch. I've got a wire hanging fromthe tranny that is probably it. Where *would* it connect to on the stock ECU/harness, and is there any benefit and hookit up right if I started with an auto body/chasis?

WAYNE88N/A

Kenteth- you could connect your 5th switch to the black/blue wire that terminates at pin 1I of the ECU (S4). On an auto this runs to the overdrive oil pressure switch, but the ECU uses this same pin on the manuals for the 5th switch. See FSM wiring, page 50-28 (for the n/a's)

Mark- considering I've been using/reading schematics and component cutaways for years now (and formally educated in their use, at that), I find it hard to believe I am misinterpreting 2 different tests and a cutaway drawing...But, wouldn't be the first time I've been wrong, and it definetly won't be the last...I'm going to look into it further

Kenteth

any idea on the s5 pin out?

WAYNE88N/A

Look it up on your FSM wiring manual (you gotta have one of those by now, right?), about the same as an S4, I would think...

Or, if you have the ECU pinout & voltages picture in your FSM like the S4's do, just look for the overdrive pin# on the ECU plug drawing...

HAILERS

If I remember right, I made a post several months/years ago wondering about the fifth gear sw input at the ECU. Especially when looking at the CONTROL UNIT read outs for each pin on the ECU.

I got to wondering when I did my na to turbo project. It appeared the CONTROL UNIT readings for the turbo vs the non turbo were.....confusing.

One thing I know for dead certain, is that on a turbo car, when you go to fifth gear, you put a ground on both the ECU's pin and the Split Air Solenoid.

The other CERTAIN thing I know, is that on a non turbo car, when you go to fifth gear, the ECU puts a ground signal on the Split Air Solenoid (see the difference in the turbo vs the na? Turbo...direct ground on the Split Air...non turbo...indirect ground thru the ECU to the Split Air).

P.S. I'm still surprised no one jumped my candy *** about how I said I grounded the Blue/Yellow wire on the wiper sw to make it run. I was dead wrong. It was the blue/white. Memory problem. Wiper switch still s..ks.
If I look at the fsm and the control unit, it gives me a headache when I think about fifth gear. Someday when I'm in the mood I'll look again at the pinouts. Not today. I'm still dealing with a new oil sucking/consuming hybrid turbo. Gave the thing back to the turbo shop and put my old turbo back on and am going to drive it a couple hundred miles and see if there is dripping oil STILL in the intercooler and turbo inlet duct. I doubt I will find that. Something went wrong with the new hybrid imho. Jury's still out. I'm getting fairly efficient at R squaring turbos.

WAYNE88N/A

Hailers and Mark- I finally got all the FSM & wiring manuals in one spot and started looking in to the "split air" thing. Hailers, you are right- the ECU grounds the split air in 5th. The book DOES contradict itself between the voltage checks and the physical "put your finger here and feel for air" checks, but all 3 voltage checks on different pages agree with your version, Hailers. I was assuming Mazda wanted a "power side" voltage check, instead of the "voltage drop across the solenoid" type test it calls for- once I looked at the wiring manual, it all became apparent. That, and it sounds like you've actually gone out to the car and played with this sucker, Hailers, so that's all the proof I need

I was wondering about that "grounding the blue/yellow wire" thing, but I didn't look into it further, and like all the rest of us, figured you knew what you were talking about...I'll keep a better eye on you from now on, lol...Sorry about the turbo, man

Icemark

The book does not contradict itself. It describes exactly what happens when the wiring is still connected and the unit is tested with a multi-meter.

I don't get why you think the book is wrong. It is exactly right.

WAYNE88N/A

Dang, I should've written down the test & page number, but I pretty much put the whole thing on the back burner after I posted above, Anyway, like I said Mark, all the voltage checks tests are good-none of them "contradict" each other. However there is one "physical" test that has you feeling for air at the split-air pipe at the back of the LIM area without telling you to put it in 5th gear (the test was at idle or thereabouts). Had something to do with the switching solenoid, IIRC.

In any case, I ain't concerned with it anymore, I've satisfied my curiousity about the whole thing, now it's on to more enigmas...

Sesshoumaru

iTrader: (1)

I have no objections with fixing the car properly.

My point is -if i gain nothing from it why fix it with a switch.

I have other places that require money and if don't notice or is no change -i'll wait.

WAYNE88N/A

I think what Mark is getting at, is that you'll also run leaner mixtures in all other gears, which may or may not hurt you on a "spirited" acceleration...

Sesshoumaru

iTrader: (1)

From what I understand is that this "altered" state is only on light load or closed loop.

once you give it gas the shift-up light goes away and is no longer in closed loop mode.

WAYNE88N/A

When checking the O2 feedback system per the S4 FSM, the 5th gear switch is not even mentioned, but the neutral switch is, which leads me to believe you can perform a closed-loop operation in any other gear also (although I would bet it would be kinda tough to do in 1st or 2nd gear).

I've got the "real time" CEL LED's in my car, and I've learned from watching them that the O2 sensor code will flash as soon as she warms up a bit, just seconds after the (cold) car has started, as long as the rpm's aren't over 1500 or so (1750 rpm is the "magic" number the book calls for to test the feedback system, so an educated guess would be that the "on-off" switch for feedback correction is 1500 rpm, regardless of gear position.

As soon as she's warm, the O2 sensor is continuously feeding info to the ECU, and I believe once the voltage starts settling around the .3 to .6 (or so) mark during normal cruise, the closed loop function kicks in, and the ECU schedules the fuel until the .4 to .5 volts is reached, and maintains that ratio as long as the peddle position (TPS???) remains constant. She will bounce back and forth between .4 and .5 , a couple of times a second, as long as your cruising...

Most of the above is conjecture based on a couple of facts, if someone out there knows exactly how this system works, feel free to educate us further

Next time I have my O2 sensor outputs on a meter while driving, I'll try to get closed loop in 4th gear just for $hits and grins...

Sesshoumaru

iTrader: (1)

seems logical

I always thought it was gear related but it would make more sense if it wasn't.

Icemark

5th gear switch is called "over the Top" switch in the manuals... that is why you didn't find anything on it.

if you look it turns the split air solenoid on in 5th, as well as tells the ECU not to use the shift up light (on S4 models).

So you conjunctures leave out what the split air solenoid does... and simply hope that the ECU can modify the signal enough to keep the exhaust gases at acceptable levels.

WAYNE88N/A

1) Yes, Mark, I know what it's called

2) I also figured out that the switch is actually closed in every other gear, and opens the circuit in 5th (this can be verified by noting the FSM has you checking for 12v on pin 1I in 5th gear, if you have voltage, then the ground is broken, i.e. the switch is open)

3) We aren't worried about what the split air solenoid is doing as far as the O2 feedback system is concerned, and that is the topic we're talking about now

Icemark

man you just do not understand auto electronics do you???

You are again not understanding...

Open means that the switch can not conduct electricty through it. Closed means that the circuit can complete itself.

The reason it is show no voltage is because the circuit is completed... it will only show voltage when not completed (I/E - open).

SO how it works???? When you are not in 5th gear, the ECU is sending 12 volts down the line (the black/blue wire) to the switch. The other wire of the over the top switch is black and goes directly to ground (do not pass go, do not collect $200).

When the switch is in 5th gear, that 12 volts from the ECU completes the circuit to ground. I think you understand that, but just are lost on the actual operation.

And you need to be concerned with the system if you are paying any attention to the O2 sensor, as the O2 sensor changes resistance based on the airflow in through that split air valve (basiclly if the air is being dumped into the cat or the manifold).