VIN# 16951 - August 1982 - Manual - Black Interior

[Admin-bloke]

If shorting the oxygen sensor input wire to earth does nothing to the dwell reading, then the fuel computer sounds like it is bad.

First though, double check that you do have an earth at both pins 5 and pin 16 (they both need to be earthed! )

If that doesn't change, try taking a dwell reading from the red/brown cable from pin 15.

Tip, you can disconnect the multi plug from the fuel by pullingback on a metallic tab andthen lift up the mulri plug. The plug is hinged at the right when looking down on the plug. Then, unscrew the screw at the end of the long thin black multi plug on the wiring loom. You can then slide the cover off that will then expose the wires. You can then plug the socket back in to the ecu and then do tests direct at the ecu.

Listen and check if the frequency valve is buzzing too. If it isn't then you might be trying to read a value but you'll just have an incorrect type of relay in the lambda relay. With the engine running you should have 12v at the green/ yellow wire at the ecu AND also 12v at the red/purple wire at the frequency valve. If you don't then that'll be your problem.

As a note, with the engine cold (lambda switch closed) OR the full load throttle switch closed, the dwell reading should be about 54 degrees and this over rides what the oxygen sensor input is.

Good luck

[Domi]

During all the test, the Lambda was disconnected.
I don't know if this matter or not.

When you talk about pins 5 & 16, you mean the connector on the computer behind the driver's seat?

Yes, the FV is buzzing.

Lambda connected, and when I push the throttle switch, the dwell read 54 degrees.

I will print all the explanation and do it when my mind will be clear, once again thank you very much for your time and help

[Admin-bloke]

No problem.

Yes pin 5 and 16 is at the fuel computer multi plug that is on the fuel computer itself behind the drivers seat.

Hopefully it'll be something simple like a bad wire that goes from the oxygen sensor to pin 4 or something.

[Domi]

All right, thanks again.
Here the two videos from a few hours:
https://youtu.be/AZCLd6tQrQk

https://youtu.be/g4kSr3pLXec

[MikeWard]

Domi, you should be seeing something similar to this, assuming the o2 sensor/ fuel computer is working properly. Taken after a 20 minute run.

https://youtu.be/DB5pSdGc2fM

[Domi]

Didn't have time to work on the car, but your video is giving me a good idea of the result I should have.
Thank you very much

[Domi]

The plug on the fuel computer seems good to me, it doesn't move at all, so I guess wiring is fine.
Still testing so far:

IMG_6154.JPG (86.11 KiB) Viewed 3080 times

IMG_6162.JPG (68.3 KiB) Viewed 3080 times

Video:
https://youtu.be/wflPfEFa5b0

[Admin-bloke]

If shorting the oxygen sensor input wire to earth does nothing to the dwell reading, then the fuel computer sounds like it is bad.

............

Have you done this test yet?

[Domi]

Oops, I think I forgot that one, I'm sorry.
So, if I understand correctly, the lambda probe must be still connected to the blue wire and at the same time I plug another wire to a ground? Right?
I don't want to do a mistake and damage something.
Thank you again for your kind help, appreciated.

[Domi]

So, here is a video to show you how I connect the wire.
First of all I have disconnect the lambda probe, and connect another brown wire to the blue wire and then goes to a ground terminal.
The Dwell value is still the same, in both case. (connect to earth or not)
Two year ago, my ECU was good, do you think while the engine wasn't working all this time may cause a defect ECU?
I've change mine in 1997 if I remember correctly. Same problem of idle.
Maybe I can plug my bad ECU (which I still have it somewhere) and see if the result are the same.
In that case, I'll know if its dead or not?
What do you think?
https://youtu.be/Qm6EHkUfhG4