ECU problems
08-03-10, 09:07 AM
#1
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ECU problems
Hi Guys and Gals
New guy here. I have owned 7 RX7's and I think this car, I have now, is probably the last. I was thinking of getting out of this RX7 thing but I just really like the cars. I was thinking about of getting rid of my 88 because it was sitting for about 4 years adn I thought it had see its better days. I finally started driving it again and you know, even though it's 22 years old, it's still best sports car ever built. Its drives OK but a lot of things are going wrong with it. So I decided to make this one a project car.
The 3 major things I want to fix are........ Drum roll please.
#1. No signal comming from the ECU.
I use the standard LED test light but nothing happens. Zilch! Nada!
2. Car Idle at 1500 RPM.
Well if the ECU is not working properly then I know I won't ever get it to a 750- 800 RPM Idle.
3. Excess exhaust fumes.
Associated with ECU maybe? Hummmmm. Can't even ride the Hotties in my RX like I used to. They say it Stink, or Stank! WHAT EVAUH !!!!!!!
4. etc etc etc...... Ok you guys get the picture lots things going on with this one.
Oh seems like I have a lot of shorts in my switch that comtrols the wipers. I think its a grounding problem but thats project #2.
Project #1. IF I use the standard ECU LED test and I get no codes, what areas should I look to get the ECU CODE. I mean, the LED's don't come on at all. You know the standard 3 sec when both LED's should light up, to show the beginning of a test, this code dosen't even show up.
Ok, FC GODS, you Titans of the Rotory. You have a new subject and I am all ears. Peace out.
7 7's
New guy here. I have owned 7 RX7's and I think this car, I have now, is probably the last. I was thinking of getting out of this RX7 thing but I just really like the cars. I was thinking about of getting rid of my 88 because it was sitting for about 4 years adn I thought it had see its better days. I finally started driving it again and you know, even though it's 22 years old, it's still best sports car ever built. Its drives OK but a lot of things are going wrong with it. So I decided to make this one a project car.
The 3 major things I want to fix are........ Drum roll please.
#1. No signal comming from the ECU.
I use the standard LED test light but nothing happens. Zilch! Nada!
2. Car Idle at 1500 RPM.
Well if the ECU is not working properly then I know I won't ever get it to a 750- 800 RPM Idle.
3. Excess exhaust fumes.
Associated with ECU maybe? Hummmmm. Can't even ride the Hotties in my RX like I used to. They say it Stink, or Stank! WHAT EVAUH !!!!!!!
4. etc etc etc...... Ok you guys get the picture lots things going on with this one.
Oh seems like I have a lot of shorts in my switch that comtrols the wipers. I think its a grounding problem but thats project #2.
Project #1. IF I use the standard ECU LED test and I get no codes, what areas should I look to get the ECU CODE. I mean, the LED's don't come on at all. You know the standard 3 sec when both LED's should light up, to show the beginning of a test, this code dosen't even show up.
Ok, FC GODS, you Titans of the Rotory. You have a new subject and I am all ears. Peace out.
7 7's
08-03-10, 11:32 AM
#2
1. Not being able to check engine codes doesn't mean the ECU is not working. The LEDs may just be hooked up backwards. The wires are polar, so switching the wires will not work. All-in-all, not being able to check codes on an S4 isn't the end of the world. There aren't many codes to begin with, and all components can be tested per the FSM. Check the FSM fuel and emissions section for tests including voltage at the ECU pinouts.
http://www.rotaryheads.com/PDF/2nd_gen/index.html
2. If idle speed never drops below 1500 RPM, the fast idle cam/thermowax assembly may not be working. When the engine warms, the piston on the thermowax is supposed to move and allow the throttle plates to gradually close. There is a cam that rotates at the end of the piston, which makes this adjustment.
It's also possible someone has played with the throttle stop, and the thermowax is now doing nothing.
3. Do you have the air pump hooked up? How about catalytic converters? An open-exhaust car with no emissions equipment will smell at idle because it's running rich. You can adjust the variable resistor to change idle mixture, but it will refuse to idle smoothly if you move it too far lean.
http://mazdarx7.iougs.com/idlecontrol.shtml
http://www.teamfc3s.org/info/article...odes/main.html
http://www.rotaryheads.com/PDF/2nd_gen/index.html
2. If idle speed never drops below 1500 RPM, the fast idle cam/thermowax assembly may not be working. When the engine warms, the piston on the thermowax is supposed to move and allow the throttle plates to gradually close. There is a cam that rotates at the end of the piston, which makes this adjustment.
It's also possible someone has played with the throttle stop, and the thermowax is now doing nothing.
3. Do you have the air pump hooked up? How about catalytic converters? An open-exhaust car with no emissions equipment will smell at idle because it's running rich. You can adjust the variable resistor to change idle mixture, but it will refuse to idle smoothly if you move it too far lean.
http://mazdarx7.iougs.com/idlecontrol.shtml
http://www.teamfc3s.org/info/article...odes/main.html
08-03-10, 12:05 PM
#3
Do as RR88 suggests concerning switching the LED lights and verify that they indeed work by using both the battery terminals for a positive and ground source. If the lights don't come on then switch the leads to the lights w/respect to the battery terminals and see if they light up. If they don't then the lights are damaged.
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