car wont start when hot.....

Discussion in '1994 - 1995 Specific Tech' started by Green 94 5.0, Mar 26, 2007.


  1. Green 94 5.0

    Green 94 5.0 Founding Member

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    #21
  2. final5-0

    final5-0 Mustang Master

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    Good to see you had some forward progress :D

    I can't deal with your CalEdit file as my older software won't play nice
    with your newer version but I'm sure some of the other knowledgeable
    Tweecer folk will get involved here and offer their input.

    I can look at your dlog and see if I see anything later this afternoon :nice:

    Grady
     
    #22
  3. final5-0

    final5-0 Mustang Master

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    OK Roger

    After thinking about what we were trying to do here ;)
    I decided to do this the easy way :nice:
    and
    Just blew off using EA :)

    I just threw your data in Log Analyst which allows me to quickly
    switch from raw column data to graphical data :banana:

    I quickly saw the following :D

    Good Pay Load choicees btw Roger ... thank you :nice:

    1 this was at idle
    2 ect range ... a bit over 100 to almost 190
    3 most of the file had inactive K's ... I suspect you did a pcm reset pre dlog
    4 at around data sample event 4740 the K's went active
    5 K's climbed steady from that point on to around 1.08

    This is an indication you are lean at idle :)

    You see the K's adding fuel
    while
    You see LAMBSE values commanding fat ratios

    I'd load in inj offsets for 42's
    Cut your minimum pulse width in half
    Reset the pcm
    Do another log

    btw ... be sure to give it enough time for the K's to do two things

    1) start to go active
    2) see how they are gonna react ... + or - fuel

    One last thought here :D

    Are you using your original maf transfer values :shrug:
    or
    Have you done any +ing or -ing to the cell KG values

    Grady
     
    #23
  4. Green 94 5.0

    Green 94 5.0 Founding Member

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    by injector offsets are you talking about the slopes? if so, with the injector slope high and low at 42 it was surging and hot starts were a no go. as far as the maf transfer, the meter is a pro-m 77mm cal'd for 42's S/C. i leaned out the entire curve 5% and the burning eye sensation went away along with the surge.
     
    #24
  5. final5-0

    final5-0 Mustang Master

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    No Roger ... but ... They do work together ;)

    Injector offsets are actually a function called Injector Offset vs Battery Voltage
    in my software :D

    I hope its still the same in your newer version :shrug:

    Basically the offset will compensate when the battery voltage varies ......
    which btw ... it can vary a good bit :eek:

    The extremes here could be thought of when you got no accessories
    on one end and say a dark rainy day for the other when you got your
    wipers, head lights, ac (defrost function), etc on and are pulling a heavy
    drain from the battery.

    anyway ... each size inj has offset values and you need to load them
    in your file. You can find those values on the Tweecer site.

    Now ... about those slopes :D

    Your slopes, high and low are a way to further tune the Closed Loop
    part of your tune. Low slope value is for smaller pulsewidths and
    High Slope comes into play as the pulsewidth gets larger.

    The j4j1 has equal slope values but I have found better stability
    with not using equal values myself.

    Here is a little rule of thumb for you :D

    The farther apart your high/low slope values .....
    The higher in value your inj offsets are gonna turn out to be ;)

    EA has excellent info that gives insight to all these inj settings btw :nice:

    I've seen many times peeps say the typical ProM sc maf cal is too
    fat on the lower end of the curve and most of the time ...
    they said it needed to be leaned out a bit.

    I'd not lean anything in the curve that pertains to Open Loop (typically
    the top half) until you get around to WOT tuning if you ask me :)

    Between some basic stuff on my site and the help files you find in
    EA you should come away with a pretty good understanding about
    dialing in your injectors with just a bit of reading ;)

    Hope some of this stuff helps you Roger :D

    Grady
     
    #25
  6. Green 94 5.0

    Green 94 5.0 Founding Member

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    being that i have no accessories but the alternator, do you really feel this is a point i need to dedicate time to? also as far as the MAF transfer goes, it was a shot in the dark so the quickest thing i could do was to just lean the entire curve. i agree 100% with your comments about OL, so i am going to return the values in that range to the original values which to my understanding are 3% richer than normal across the board with the s/c calibration. what MAF voltage would be a good starting point to richen it back up in the MAF Transfer function?
     
    #26
  7. final5-0

    final5-0 Mustang Master

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    Its not like you gotta put a lot of time or effort in the change. You just plug in the values for your 42's. You can fine tune things a bit with these values if needed. But ... Yes ... I'd load them in as you now have inj's that are twice a large as the pcm thinks are being used.

    Sure ... You gotta try things and see what happens!

    And Yes ... there is usually more than one way to go about making things better.

    Working with the various inj values like slopes, offsets, and breakpoint, will ... IMHO ... yield you a more stable Closed Loop portion of the tune than just working with the maf curve.

    Now ... You will most likely find a spot or two in the curve that will need a bit of adjustment when you get your tune close and are working on the fine tuning.

    Heres the deal ... You strive to stay in Closed Loop while working with the inj values.

    When dialing in the inj values for a stable CL tune, you will see trends develop in your datalogs. Look for what I call the breakpoint in the maf curve that seperates Closed Loop from Open Loop.

    For my combo, I found 2.6 maf volts was the highest I ever recorded while still in CL.

    When I started to work on my final WOT af ratio which involves working with fuel table and maf curve ... I made sure I did not change any part of the curve from 2.6 and below as I did not want to wipe out all my work in the CL part of the curve.

    With your blower, I could not even guess how that would effect things here but ... I'd have to guess it would.

    Grady
     
    #27
  8. 99FiveOh

    99FiveOh Advanced Member

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    I don't have a tweecer, but the SCT tuner that did my tune said he needed to modify something to fix my hot start problem, which is the same as you guys have. Started doing this after my tune.
     
    #28
  9. Yellow302

    Yellow302 Member

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    SCT chip same hot start prob with 42'lbs

    changed pulse width to 0 and added some air to the crank iac worked like a charm :)
     
    #29
  10. BobCat

    BobCat New Member

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    ;) glad to hear it
     
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  11. final5-0

    final5-0 Mustang Master

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    I've been meaning to give you an Offical 94-95 :SNSign: welcome

    Good to see another self tuner join in with the rest of us :D

    We look forward to your input and hope to learn from it :nice:

    Grady
     
    #31
  12. Green 94 5.0

    Green 94 5.0 Founding Member

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    hehe...it looks as if he has been around longer than both of us, just not as vocal.
    :)
     
    #32

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