Gday, Im wanting to find out why the mazda is overfuelling. It is a B6ZE DOHC engine. It overfuels when cold and warm but worse when cold.
Are there common things that go wrong and cause overfuelling in these car! I think its overfuelling because of black smoke when you open throttle and sooty plugs. The ignition timing is correct, air flow meter appears to be working fine, fuel pressure is 30psi with vacuum and 42psi without or when you open throttle. Temperature sender for ECU I think works, well the ECU seems to respond to it as the car warms up so I assume it is working but without a thermometer I cannot really confirm that the resistance is correct.
Systems not active: ISC valve (because it is seized), Fuel tank vapour system solenoid disconnected, Temp gauge connected to original mazda 121, Coolant thermoswitch on thermostat housing is broken (I think this drives the fans but fans controlled by ECU it appears)
Any ideas!
mm12345,
Feb 4, 3:35am
O2 sensor perhaps!
morrisman1,
Feb 4, 3:43am
any way of cleaning them! I did unplug it and no change to the emissions. It is 23 years old I presume so probably about as effective as scotty's supercharger
flashgordon_nz,
Feb 4, 4:04am
what computer is running it!
morrisman1,
Feb 4, 4:10am
stock computer
mm12345,
Feb 4, 4:11am
Supposedly carb cleaner or clean petrol. .but O2 sensors are expensive. You can apparently check signal voltage at ~2000rpm on a hot motor, should fluctuate/swing every second or so between about 0.2 and 0.8V. If disconnecting it didn't make any difference at all, then check wiring too. Ideally, borrow a known good one, and try it out, including comparing signal voltage if possible. Problem is that you're not going to know immediately whether it's running rich because the O2 sensor's dirty, or the O2 sensor's dirty because it's running rich for some other reason.
flashgordon_nz,
Feb 4, 5:04am
Hmmm. ok, the stock computer does, or can store fault codes. it would be a case of trying to get them out. LOL
morrisman1,
Feb 4, 5:10am
yea, I dont have a check engine light haha, I might have to look at wiring one up. I did find a guide somewhere on how to make it output the codes and there is something in the workshop manual about it too but that expects you to have a million dollars worth of special service tools!
The computer will probably throw a heap of codes with the amount of random/unnecessary stuff that isnt connected in the conversion.
un_known,
Feb 4, 12:18pm
ok for the codes just put an led between the b+ and fen pins on the diagnostic connector. works the same as a cel. the + goes to the b+. atleast i think thats right been awhile since ive done it.
Hi folks, I have a 1989 Mazda Familia with the carburetor B5 engine. there are a few issues which are presenting themselves.
1. The engine when it starts idles at 1500RPM cold, then when it warms up it idles at 2000RPM, what could be causing this.
2. How do I adjust the kick down cable, should it have spacer where it sits in the cradle between the adjusting nuts
3. is there a vacuum connection between the carburetor and the transmission that correlate gear changes
please help ?
Since the public registrations are closed, you must have an invite from a current member to be able to register and post in this thread.
Have an account? Login here.