Protection Relay Conversion and Fuel Distributor Starting Alignment | Page 4 | FerrariChat

Protection Relay Conversion and Fuel Distributor Starting Alignment

Discussion in '308/328' started by Steve Magnusson, Sep 16, 2009.

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  1. olehholy

    olehholy Karting

    Nov 12, 2003
    122
    NJ
    Full Name:
    Oleh Holynskyj
    Well another disappointment, the air injection seems to be working as you described in the 3 stages. I was really hoping we uncovered something with the electrovalve. This is what I found:

    Upon stone cold startup, I felt no suction on the line going to the cut-off valve so I presumed this was Stage I. Oddly enough, the temp outside is very warm today so I was surprised that the thing started with Stage I.

    After about 4 mins of warm-up, I heard the burbling start and I felt strong vacuum at the line going into the cut-off valve. Sounds like Stage II

    Relativly quickly after that, perhaps 2 mins if that, I heard the burbling stop and I felt the vacuum at the cut-off valve also stop, This I assume is Stage III.

    Sounds like it is working as expected.

    Well I am at a loss.

    Throughout all of this, 2 things remain constant:

    1. Duty cycle is locked on 90%, cold, hot, O2 sensor in, O2 sensor out, it doesn't matter
    2. Car stalls very quickly after O2 sensor is disconnected.

    Now I need to figure out what the hell I could have done to kill my hi-idle cold running.

    Oleh
     
  2. olehholy

    olehholy Karting

    Nov 12, 2003
    122
    NJ
    Full Name:
    Oleh Holynskyj
    Well, I do have some news on this issue as I have been able to turn some attention to it.

    I believe the issue to be more of a duty-cycle measurement methodology and meter type (as Steve Magnusson suspected earlier in this thread). As a review, I was getting a duty-cycle reading of about 80% regardless of open/closed loop, O2 sensor connected/disconnected, etc. This lead me to believe that I has some defective electrical problem. As a result, I did everything from replacing several of the temp sensors to a new Bosch computer and even a cat ECU.

    The measurement methodology I used was to leave the FV connected, pull back the rubber boot from the back of the Bosch connector on the FV, and insert the leads from my duty cycle meter. I used an ACTRON digital duty cycle meter as well as a Snap-on MT-917 analog duty cycle meter. Each reported a fixed duty-cycle of about 80% regardless of running condition using this method

    However, I then chose to disconnect the Bosch connector from the FV and measure the signal directly and ran the engine through the various warm-up routines, etc, this resulted in both meters showing the expected behavior, a fixed 50% duty cycle during warm-up or with O2 sensor disconnected, and a 26% duty cycle (in my case because I know I am running very rich) closed loop and O2 sensor giving output.

    I came to the conclusion that my particular meters, and perhaps others, may mis-read the duty-cycle values due to feedback or something from the FV coils while it is running. I've had several inquiries via PM from folks who are seeing the exact same behavior, as to whether I was able to get to the bottom of this. I would advise them to also disconnect the FV and see if the computer';s output is as expected by measuring at the FV harness.

    For those who have been able to measure reliably with the FV connected and running, please post the make and model of the meter you are using.

    Thx,

    Oleh
     
  3. alfa-guy

    alfa-guy Rookie

    Jan 27, 2004
    42
    Oleh -

    Everything I've learned about testing components, and using the instruments tells me that the proper way to measure the duty cycle at the frequency valve is with a running (warm) engine, and back probing the connector at the Frequency valave (leaving the connector connected).

    This is the only way you can set the mixture 'dynamically' by measuring the duty cycle.

    That being said, as you know I'm having what appears to be the same problem with my QV. And in my case, the duty cycle reads correctly with the Freq. valve disconnected, but incorrectly with it connected.

    I don't know what to think anymore, I'm very frustrated and have wasted an awful lot of time on this.

    I'll let you know if I have any breakthroughs ...

    Jeff
     

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