rx-7_2my

My -86 converted to Turbo II (the block and intake manifold is bridge ported, but from an N/A rx-7, about everythin else is TII) won't run for more then a second, then dies, unless I push the mass airflow meter halfway in. then i can get it to run as long as I want, but if I touch the throttle, it chokes instantly. My guess is that the O2 sensor is wired wrong. I'm a dyslectic when it comes to reading wiring diagrams. For some reason the O2 sensor wire was cut off, probably in both ends of the connector, so I jumped it to a single, grey double insulated wire, coming out of the engine harness next to the alternator, but i still have the same symptoms, with the O2 sensor jumped or not. So now I have a few questions:
1. Where does the wire to the O2 sensor come out of the wiring harness, and wich harness (and which color)?
2. Could this unconnected O2 sensor have caused this problem, or is it maybe some other malfunctioning sensor?
3. Is there a way to check that all sensors are operating? maybe with a voltmeter?
4. Does the O2 sensor produce a small amount of electricity, or does it receive electricity from the ecu, and the ecu measures how much electricity that passes, depending on how much oxygen in the exhaust?

I hope someone is able to help. It's difficult to reassemble a car somebody else disassembled. If it helps, i could take some pictures. I also want opinions on installing megasquirt 3.0 on my car, or some other computer injection. All contributions is appreciated. Greetings from Norway...

RX3SP

iTrader: (62)

You need to check for air leaks between the throttle body and the AFM. It sounds like you have a leak allowing unmetered air to enter the engine.

rx-7_2my

Already tried that. I hooked the AFM directly to the throttle body, and still had the same problem. Sprayed with start gas all over the place, and no response.

RX3SP

iTrader: (62)

The leak could also be on the intake manifold somewhere. Between the intake and the engine, power brake booster line, etc. Anywhere it can draw in unmetered air. As far as the O2 sensor goes, the engine will run even if it's not connected.

rx-7_2my

Ok, I'll give it another shot, but i still think i should connect the O2 sensor anyway. Btw, the idle controller. How should that hose coming out of it really be connected? Before or after the throttle valve?

PatrickT

before the throttle and after the afm.

before the throttle because the BAC is bypassing the throttle
/the BAC itself is already flanged and connected to a location behind the throttle
after the afm because the air also has to be metered

and of course 100% leak-proof

-Patrick

arghx

iTrader: (3)

O2 sensor has nothing to do with this at all. It does not operate under cold start conditions--the vehicle is in open loop and does not use O2 feedback.

rx-7_2my

but some day, i will be needing my O2 sensor, so if anyone could tell me, where the wire to it comes out of the harness, that would be nice. Also wondering how it works.

rx-7_2my

And is there some way I can find out i my afm is working? Nobody in my neighbourhood or town has a fc3s.

tuns0ffun65

unplug the afm and take it out and see what it does, if i runs better then you need an afm, if it doesnt run at all then your afm is fine, also check to make sure you have the correct fuel injector resistor box , up by the passenger side head light, that could be your problem but this sounds more like vaccuum leaks to me, seeing as how you open the afm and it runs

NCross

iTrader: (18)

Check to see that the throttle plates are working properly. Is the throttle body modified? Check to see that the fast idle stuff is in order. Cold start too.