graniteguru

iTrader: (1)

Question on an 89 TII RX7 JDM conversion. I am having a problem with the engine starts to spit and sputter when I put it in first gear. It kind of sounds like it starts running on 1 rotor. When I checked the 5th gear switch, it is getting 12 volts at the ecu terminal in 1st or 5th gear. It is supposed to get less than 2 volts when it is in 1st through fourth gears. And then in 5th or reverse, it is supposed to get 12 volts. I have 12 volts in both gear positions.

Question is this. I am using a JDM transmission and engine. On the 5th/reverse switch on a JDM, there are only 2 wires. My understanding is this is reverse lights only as the JDM does not use a 5th gear switch. I am using an american harness and ecu.

Is the switch bad, or am I doing something wrong with the wiring on the JDM.

HAILERS

The Japs don't use the over the top switch or fifth gear switch if you will. That is why you only have two wires on your transmissions reverse switch, instead of four.

So, there is no input to the ECU from the switch becasue.......it does not exist. ON a working USA car, you go to fifth and put a gnd on the wire going to the ECU which in turn drops the voltage of that pin of the ECU from 12vdcwhatever to less than two volts.

All the fifth gear or over the top switch does in life, if memory serves, is to actuate the split air solenoid on the ACV to open in fifth gear. Does so on a series four anywway. Probably the same on a series five.

There is no split air solenoid on a Jap ACV. Make sense now? yes

graniteguru

iTrader: (1)

Makes sense to me Hailers. Thanks. What does not make sense is that I now have the reverse lights only hooked up to the reverse switch and the two other wires just tied back to the ecu. Still when I put it in first gear, the car starts to sputter like it just lost a rotor or spits and sputters.

HAILERS

The first two jpg are for series five. You'll have to see the page CONTROL UNIT in the FSM for Turbo to be able to read it. By the way, look at CONTROL UNIT for the NON TURBO car also. There is a difference b/t turbo and non turo. More things are effected on the non turbo. I need to think about how this works b/t the two.

Last jpg is series four. You can see the fifth gear switch and how if it *makes*, a ground is put on the ECU pin. That drops the voltage seen at the ECU and also puts a gnd directly on the Split Air Solenoid when in fifth.

Looking at Control Unit page for a series five non turbo, it seems that making the fifth gear switch effects the Split Air Solenoid and a couple of other things effect the Split Air Solenoids operation. Like the pressure sensor, a/t oil pressure switch, neutral and clutch switches all effect the Split Air Solenoid.

None of that bs seems to have anything to do with what your problem is.

HAILERS

Yeah. Your fifth gear switch is wired wrong. You should see 12v on the ECU's pin until you go into fifth gear. When you go to fifth, you put a ground on that wire and the voltage FROM the ECU drops to less than 2vdc.

Hey, I'm too lazy to read all the above again. The JDM transmissions have no fifth gear switch, so lets figure out what happened. By the way, the two wires on that switch should be the reverse lights wires.

Well if you used the non turbo wiring, you had nothing to connect the fifth gear wires to. So I can't tell from here what is wrong. There should be no coming and going of voltage at the ECU. It should read 12v all the time at that pin.

The wiring from the fifth gear switch (if it exists) is the same routing on a turbo car as non turbo car. I think you've got the fifth gear switch wires going to something else. Although I don't understand. Just what voltae do you see in gears 2nd and 3rd?????? To my mind the voltage should never change becaue you have no fifth gear switch to make things change.

WARNING, WARNING, WARNING: I just looked at the pinouts in the ECU for both Turbo and Non Turbo cars.
The input/outputs read assbackwards b/t the two for pin 1T. This is either a printing BLUNDER or the switches in the Turbo are backwards from non turbo car.

I look at both diagrams and see that if the fifth gear switch is made, then the voltage should drop from 12v to less than two volts. In 2nd - fourth it should read approx 12vdc. I say the non turbo reading for fifth gear is WRONG.

Then again. you have no fifth switch if it's a JDM transmission. Only the reverse switch. Only two wires for..........reverse. Is that what you have? Two wires? Left rear of the transmission?

HAILERS

Sorry. It might have gone faster if I had read your post a little bit better the first time I looked at it.

Again, since no wires are going to the pin 1T (not connected to anything since there is NO fifth switch), going into fifth should SEEMINGLY have no effect on the output of pin 1T.

The wiring for non turbo and turbo are the same if the dwgs are right, and I think they are.

Then again ...again, going into fifth gear should only effect the Split air solenoid on the ACV and that isn't ENGINE related in my humble opinion. It just energizes in fifth and feeds airpump air directly to the converter.

The two wires on the harness that went to the fifth gear switch have nothing to connect to. So the questio is, are they just hanging in mid air or??????????????

Also, assure me this was never a automatic car. Thank you.

graniteguru

iTrader: (1)

Hailers This was an automatic transmission car. I am using a series 5 auto transmission harness. Now that I have the 5th gear (actually now just a reverse light switch) hooked up correctly, the two wires that were going to the 5th gear/ reverse switch are just capped off right now. If the car is idling, it will start to sputter when put in any gear. Since there is not a connection to the 5th gear switch any more, it must be something happening with the neutral switch. That switch is the only one now that is sending a signal to the ecu that the car is being put in gear, unless there is a connection between the reverse lights and the ecu. I do get reverse lights when I put it in reverse.

I did remove the auto transmission control module on the car that was under the dash and left the plug blank.

HAILERS

Yeah. I'd have disconnected that EC-AT Unit just like you did. I mentioned the A/T because I saw where, on a/t cars, pin 1T gets a gnd from some automatic transmission part.

It could be the neutal or the clutch switch that's influencing things. You probably already checked them out since you did check the fifth switch input. IF not, go look at those two inputs also.

Another thing. I'd depin the wire at pin 1T. As in remove the wire and its terminal from the ECU plug. You do that by removing the plug from the ECU. Then looking into the side of the plug the wires are NOT attached, use a small jewelers common screwdriver to push the locking tab for that wire up, and at the same time pull the wire out of the plug. It should be a BL or black/blue colored wire.

I'd do that and see what happens when you go into gear. Engine fully hot.

Using a Turbo ECU?

graniteguru

iTrader: (1)

Using an N370 ECU. I did check the outputs on the Neutral Switch and all seemed to be OK, but I will double check them. I am also going to check the wires to the ecu to other components. I noticed that the G/B wire on 1R is tied together with the ECAT unit.

HAILERS

About that diagram. I MEANT to take note of how there is a section on the dwg that shows ECAT items for auto cars and to the right of that a seciton that shows only manual cars. There's only one 1R.

graniteguru

iTrader: (1)

ON the AT models, the 1R goes to the module. On the manual, it goes to the Neutral switch. I replaced the harness on this thing and I thought that I bought an automatic transmission S5. It does appear as if it is in fact a manual transmission harness. I checked the 1 R on the Neutral switch and with the ignition on, in neutral, it is getting below 1 volt. With the ignition on, and in gear (any) the voltage goes to a little less than 12volts. I also tried it with the car idling. In neutral, the car idles fine. When you put it in first, the engine starts to cycle up and down and sound like it is running on one rotor. It bounces between 900 and 1500 RPM. That 1R wire must connect to something else, or is the ECU burping because it can't find a signal from the 5th gear switch? This has me befuddled. I guess that I can try a wire from the 1r pin directly to the neutral switch. Does that make sense?

HAILERS

Fifth gear switch on the Turbo would have nothing to do with it.

1R in neutral should be less than one volt. Any other position and it's batt voltage or close to it.

Neutral switch is on the right side of the transmission. Pull it's plug off. Then repeat the checks. If you see 12v all the time then you have it connected up right. It sounds like that is the case right now.

Why does it cycle when a gear is selected.....don't know right now. Pull the wires off the neutral switch and see what happens going into gear. Clue time.

Fact is I have never really been able to tell what that neutral switches purpose is, other than let the ECU know you going for a drive. One of the things one does on a series four to see if the 02 sensor is causing the ECU to go into closed loop, is to pull the TPS plug off and the plug for the neutral switch and hold the revs to above about 1700rpm. So that tells me the switch tells the ECU "we're going for a drive now". It must alter *something* in the ECU.

graniteguru

iTrader: (1)

When I disconnected the neutral switch all together, it spit and sputtered in neutral as well as in gear. Well at least it is running like crap in neutral AND in gear now.

HAILERS

If the switch is connected back up, what happens if the engine is fully hot? Same or different?

graniteguru

iTrader: (1)

I have not tried it hot. I can't really run it any more tonight, the neighbors have small ones that might get nightmares!! you know Attack of the mutant rotarys!!
I will try it hot tomorrow night. One thing that I noticed when I had the ignition on, was that the bac valve was rapidly fluttering with the switch disconnected. When I hooked it up, the bac slowed down but still kept fluttering in other words it changed pitches. I disconnected the bac valve and it had no effect on the behavior.
What would it mean if it behaved differently hot?

graniteguru

iTrader: (1)

OK!!! OK!!!. It runs!!! I actually drove the car under boost and it runs great. As we talked about earlier, with the JDM engine and transmission, it does not use a fifth gear switch. There are only two wires coming off of the reverse switch and they are ONLY for the reverse lights. The wiring harness does have many more wires down there than you need especially if you are using an auto transmission harness. Just disconnect the fifth gear switch wires on the S5 and make sure to de-pin them (just to make sure that they don't effect anything else). In my case, the neutral switch wire (the green/black wire) was going to ground. I tried using the 5th gear switch wire and for some reason, it had no continuity. So, I just ran a new wire all the way from the ecu to the neutral switch on the transmission. Problem solved! Thanks for the help Hailers as usual, even if you don't know the answer, you work through the elimination process with all of us and help us think through the solution.

Mazdaracer4fun

iTrader: (2)

HEY is the bac valve still "fluttering" since you drove it? (fluttering when key on but not running or driving tho)