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mixture tuning on a federalized euro car

Discussion in '308/328' started by airdelroy, Apr 11, 2009.

  1. airdelroy

    airdelroy Formula Junior

    May 10, 2007
    418
    Austin, TX
    Full Name:
    Aaron Richardson
    I have an 85 euro gts that had emission control stuff to the car when it was imported. However, that system is not complete at this point and Texas emissions inspection is coming up. I had pulled the injectors and cleaned them recently, but I have not tuned it since then. The car does seem to run fine.

    The car has the following:
    jetronics box in the trunk
    2 small catalytic converters
    an O2 sensor
    something that looks like a differential pressure switch (electrically connected only, vacuum)
    evaporative recovery stuff

    The car has a WUR that does not have a vacuum tube connected to the throttle body. It does have an electrical connection that is disconnected. And of course 2 fuel lines.
    The car does not have a frequency valve.

    So, now for the questions :D
    Should I track down a frequency valve and close the loop for the system? I assume it would help emissions, but would it help performance?
    How should I go about tuning this? I have seen a few methods mentioned on tuning:
    1) Measure voltage of O2 sensor and adjust mixture for .5-.8V on the sensor.
    2) Measure dwell at the frequency valve and set to 50% duty cycle. (Would this work checking at the connector without a valve?)
    3) Locate an LM-1 and use this to adjust the mixture.

    The last option is probably the best option as I would think I can get the mixture very close. The only problem is that I have not located a loaner LM-1. As for #2, I also dont have a dwell meter and would rather spend the money toward an LM-1. I do have an O-scope and could put that on there to measure duty cycle.

    Suggestions?
    thanks,
    Aaron
     
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  3. rolindsay

    rolindsay Formula 3

    Jul 14, 2006
    1,022
    Houston, TX
    Full Name:
    Rick Lindsay
    Aaron, I'm in Houston. If you can get by waiting one more year you can register the car as an antique and you won't have to go through emissions testing! My 308GTB and my Mondial QV both wear antique plates. And if that wasn't enough of a bonus, with antique plates you aren't required to wear front plates!!! In fact, they don't even issue them! Go Texas!
     
  4. airdelroy

    airdelroy Formula Junior

    May 10, 2007
    418
    Austin, TX
    Full Name:
    Aaron Richardson
    Ya, you actually dont need to register the car as an antique. Next year they just stop testing emissions on cars made in 85. Although the front plate is a good reason to do it. Ill have to consider that option then. However, I would like to drive the car between now and then. :)

    WUR - So, Im not sure what this WUR is for, but I dont think its for this car. It does not have any vacuum input from the throttle. From my understanding that means that I dont get enrichment when opening the throttle. The car does pop some on overrun, perhaps this vacuum line would help fix that as well? The electrical heater on the WUR I found is connected, but I dont know if its working properly. Since I dont have any issues starting/running the car cold/hot Im not too worried about it. The popping I guess would be the only reason to replace the WUR with what was on the car originally.

    The vacuum in front of the throttle body is plugged. The vacuum after the throttle body runs over to an evaporative canister by the drivers gas tank.

    Ive been pretty busy and have not put a scope on the frequency valve connector, but I hope to do that tonight.

    Aaron
     
  5. airdelroy

    airdelroy Formula Junior

    May 10, 2007
    418
    Austin, TX
    Full Name:
    Aaron Richardson
    Anyone know the part number for the frequency valve? I cant seem to locate a source for this part.

    thanks,
    Aaron
     
  6. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    20,295
    Texas
    Full Name:
    Steve Magnusson
    #5 Steve Magnusson, Apr 14, 2009
    Last edited: Apr 14, 2009
    The frequency valve 121513 (not that you can buy one ;)) and the pulsation damper (item 31) are the same ones as used on a US 328:

    http://www.ricambiamerica.com/parts_catalogs.php?M=FE&P=&V=diag&I=2392

    Is it obvious in your (residual) plumbing bits where it would go? I'm having a vague recollection that on these gray market (Johnson?) systems, the FV was connected in a manner that alters the control pressure; whereas, on a real US version, the FV was/is connected to alter the lower chamber pressure.

    edit: Here's the thread where Brian Brown explains the limitation these aftermarket system using the control pressure have -- only being able to lower the control pressure -- thus only being able to add richness. They can't raise the control pressure to go leaner:

    http://ferrarichat.com/forum/showthread.php?t=175338
     
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  8. airdelroy

    airdelroy Formula Junior

    May 10, 2007
    418
    Austin, TX
    Full Name:
    Aaron Richardson
    Well, I guess if I cant buy one then that solves that problem.

    It is not obvious where it is to be attached. I will read the link and see if I can make heads or tails of it. I wonder why it wasnt done like the US cars. I guess the fuel distributor is a different part than the US cars and does not allow access to the lower chamber pressure?

    I hooked up the O-scope to the plug for the FV and I am seeing some weirdness. I seem to be only picking up 60Hz on 1 of the wires. Its about 1V peak to peak. Its not a nice sine wave either, pretty choppy. But not a square wave either. The signal does not change when the car is started. Perhaps the controller is not functional. Or perhaps I need to connect something in place of the FV to get a signal?

    Aaron
     
  9. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    20,295
    Texas
    Full Name:
    Steve Magnusson
    #7 Steve Magnusson, Apr 14, 2009
    Last edited: Apr 14, 2009
    This does not surprise me (that it's not very clear). My foggy recollection of one implementation is that they double-stacked two banjo fittings onto the top of the fuel distributor (secured by a single bolt) where normally there is only one banjo fitting. Consequently, if you were to remove the FV, you would probably remove the whole line and go back to the stock single banjo fitting. They really didn't have a choice of "how to do it" as the lower chamber pressure is always just the supply pressure on the "non-Lambda" K-Jet fuel distributors -- on the later K-Jet fuel distributors they made internal changes so the lower chamber pressure could be something different than the supply pressure.

    The way the FV works (on the stock set-up) is one wire is always +12V; the other wire is controlled by the ecu and is alternately connected to ground, and then not connected to ground, in a PWM way (i.e., the duty cycle varies to change how much fuel "leaks" thru the FV and back to the tank which changes the lower chamber pressure). Don't know how your particular ECU works, but Brian B.'s comments lead me to believe that these aftermarket systems are not as sophisticated as the stock set-up, which always has some fuel "leaking" thru the FV, and therefore, can be made to leak less or leak more (i.e., remove richness or add richness). It seems like from Brian's description like the aftermarket ECU leaves the FV fully-closed and then can only open it (i.e, so it can only drop the control pressure). All just speculation on my part, but try a search on "control pressure johnson" -- should get you some relevant threads and may lead you to other threads or give you some better keywords to search on.
    Another point is that when the engine (and O2 sensor) are cold, the ECU would have to "know" this so it would ignore the O2 sensor signal and run open-loop -- i.e., it might use the signal from the coolant temperature switch just like the stock system or have a time delay before it tries to do something with the FV. When you made your measurements was the engine "warm" and had run for a while? I think the best voltage measurement to make is just between the two wires themselves (i.e., the voltage that would be across the FV coil winding).
     
  10. airdelroy

    airdelroy Formula Junior

    May 10, 2007
    418
    Austin, TX
    Full Name:
    Aaron Richardson
    I tested the connector when the engine was cold. I was hoping to see a 60% duty cycle. But I guess you are right and this system may be totally different. I suppose it doesnt even have to run at 50% to bring the system into line. It could be something way different.

    So, I guess I will pass on reading the frequency valve. As I dont have an LM-1 (yet :D) I will try reading the voltage directly off of the O2 sensor.

    Is it worth it to try and re-create a closed loop system? It seems to me that I would gain HP and fuel efficiency by doing this. Is that not the case?

    Aaron
     
  11. airdelroy

    airdelroy Formula Junior

    May 10, 2007
    418
    Austin, TX
    Full Name:
    Aaron Richardson
    Oh, and my lambda controller box is made by Liphartd in Germany. It looks surprising like one Ive seen in a pic somewhere in fchat.

    Aaron
     
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  13. airdelroy

    airdelroy Formula Junior

    May 10, 2007
    418
    Austin, TX
    Full Name:
    Aaron Richardson
    Well, I was not getting anything from the O2 sensor either. I either didnt track down the right wire or the sensor is dead. Either way I have a new LM-1 now. :D

    It was pretty easy to get up and running. I was able to get the mixture set to 13-14 with it settling to about 14 when idling around 1100 RPM. Other than not the software not seeing my linux/wine serial ports and I had to run it on windows box I had no problems.

    As soon as the rain stops (which will probably not be till next week) Ill take it to get inspected and see how it does....

    Aaron
     

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