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FAST dual sync new install

Discussion in 'FAST Support Forum' started by HKMustang99, May 16, 2017.

  1. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    You shouldn't have disassembled the throttle body. FAST would have RMA'd it for inspection and repair. Those covers are difficult to re-install. The whole system had a limited lifetime warranty.
     
  2. Fastnofast

    Fastnofast Member

    Joined:
    May 16, 2017
    Yes i know. But i am in france and i will send the thb only if i see something wrong on it. I can repair the leak. All of the other parts seems to be ok
     
  3. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Yes, RMA's from overseas are a big problem. The oil you saw was probably left over from assembly. Be very careful with the re-assembly of the covers. They are a close tolerance machined fit. FAST uses a jig to assemble them, but it can be done without one. Olive oil can be used to help re-assembly - it won't degrade any rubber parts like other oils can.

    Good luck. Maybe you'll soon be able to perfectly tune the system.
     
  4. Fastnofast

    Fastnofast Member

    Joined:
    May 16, 2017
    Job is done ! No more leaks. Checked under pressure ok
    Thank you AA.
    Now i check entire system without MSD and FAST distributor. I connected the rpm module on my old HEI. rpm is ok on the ecu. Spark is ok on the spark plug. Tomorrow is another day. Just a question AA do you know how the FAST distributor manage the timing ? When the ecu control the timing, what's happend in the distributor ?
     
  5. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    The FAST Dual Sync only adjusts the phasing and provides a spark and RPM signal. The FAST Dual Sync has no advance, so the ECU controls all of that. The Dual Sync just supplies the ECU with the signal it needs.
     
  6. Fastnofast

    Fastnofast Member

    Joined:
    May 16, 2017
    So if the ecu want 25 degrees of advance it send the signal to the msd and the msd send the high voltage to the spark by the coil 25 degrees sooner translated to a portion of time sooner. So before the rotor is exactly in front of the post inside the cap ?
     
  7. Fastnofast

    Fastnofast Member

    Joined:
    May 16, 2017
    Hi AA. engine started this evening. With ecu and thb. Difficult to crank without playing with the throttle bracket. After few start it ran. But now the o2 sensor read 15.9 and ecu try to enrich at 25%. I stopped engine for one minute and after o2 sensor gave an error on the dash.
     
  8. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Check the O2 wiring harness connections and be sure you don't have an exhaust leak. Were all cylinders firing?
     
  9. Fastnofast

    Fastnofast Member

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    May 16, 2017
    I think that they all firing. But not enough time to check but sound seems ok.
     
  10. Fastnofast

    Fastnofast Member

    Joined:
    May 16, 2017
    I checked wiring harness. Removed o2 to see. Checked connectors. Powered on ecu and no more error codes. Install o2 on exhaust. Next try next week.
     
  11. Fastnofast

    Fastnofast Member

    Joined:
    May 16, 2017
    Hi. This evening some news. Removed o2 sensor to check AFR read on screen. Engine not running. Only ecu powered on. AFR read 15.9 as soon as ecu is on. Wait few secondes in my hand. O2 is warm so ok. AFR suddenly gives to me 14.2 then 14.3 14.4.....15.....15.9 !
    As the o2 is in the air it should give me 15.9 right ? I put some gas of a gas lighter under the o2 and no effect. This O2 is a bosch LSU4.2 with 5 wires. I check in my garage and i have an o2 sensor bosch LSU4.9. with a AFR gauge. I check it with the gas and AFR is going rapidly to 9. I remove gas and AFR give a 22.4. So it seems that the FAST o2 is bad or harness or ecu
     
  12. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    It's not unheard of for a new FAST O2 sensor to be bad. Normally, a bad one will read lean when the mix is rich. Get a replacement BOSCH sensor from a local parts store.

    Be sure not to use any added sealant to the new sensor. Sensors can be easily poisoned.
     
  13. Fastnofast

    Fastnofast Member

    Joined:
    May 16, 2017
    I ordered one i will receive in 2 or 3 days.
    AA, you didn't answer to my question about Rotor phasing.
    If the ecu wants 25 degrees of advance it sends the signal to the msd and the msd sends the high voltage to the spark by the coil 25 degrees sooner translated to a portion of time sooner i suppose ?. So before the rotor is exactly in front of the post inside the cap ?
     
  14. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Your Dual Sync took care of phasing when you set it up. That is not an issue here. With no internal mechanical advance changing rotor position, the rotor maintains a static position centered on the distributor cap posts. If you had a MSD mechanical advance model distributor with the advance locked, then you would need a MSD phasing rotor to center the rotor back on the distributor cap posts. The actual firing point position changes depending on RPM. Spark transfer does not stay dead center of posts. The phasing is designed to keep the spark gap within a nominal range - whether OEM or aftermarket.
     
    Last edited: May 24, 2017
  15. Fastnofast

    Fastnofast Member

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    May 16, 2017
    Ok AA. but i always don't understand how the ecu manage the timing. I understand that rpm is an important factor but how the ecu change the timing to simulate mechanical advance ? What's happend in the distri utor ? You say that The actual firing point position changes depending on RPM so the only way is to change the time when ecu send the signal to the ignition box ?
     
  16. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    The EZ 2.0 ECU sets timing with a programmed RPM graph - which is determined by Wizard settings but changed using user settings as necessary. Nothing other than supplying the ECU with a TDC reference signal and secondary spark transfer happens in the Dual Sync.

    "so the only way is to change the time when ecu send the signal to the ignition box"
    Yes. The ECU changes timing according to the slope and RPM graph it follows internally, and modified by vacuum if vacuum timing is turned on. The ECU reads vacuum through the MAP sensor. The ignition box just sees the firing signal provided by the ECU graph.
     
  17. Fastnofast

    Fastnofast Member

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    May 16, 2017
    Ok AA so inside the cap that's mean that the spark beginning sooner to increase advance right ?
     
  18. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    As advance increases, it moves farther from TDC in the BTDC range. Rotors turn clockwise or counter-clockwise depending on the engine manufacture design.
     
  19. Fastnofast

    Fastnofast Member

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    May 16, 2017
    You said it moves farther. The rotor ? How does it moves farther as there is no mechanical advance ?
     
  20. Fastnofast

    Fastnofast Member

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    May 16, 2017
    Good news with the new o2 sensor, crank ok, idle ok. AFR 13.5 at idle. next step, install MSD 6 and FAST Dizzy. Hope the best !
     

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