car very hard to start and bad tune??
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This is a discussion on car very hard to start and bad tune?? within the Engine Modifications forums, part of the Tech & Modifying & General Repairs category; hi guys i have decaped stock injectors a while back but im having a couple of problems with it but ...

  1. #1
    Registered User sxcrxy's Avatar
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    car very hard to start and bad tune??

    hi guys i have decaped stock injectors a while back but im having a couple of problems with it but i think is in the tune

    i know its the injectors because it happend only after i decaped them

    1st problem - starting is very hard (engine temp dependent) i think i need to adjust cranking pulse width on my tune but i need helpp because im not to familiar with that i know it runs rich because when it does start black smoke comes out of the exhaust and can smell unburnt fuel (i really need this problem fixed like i really need it done )


    2nd problem - loud bakfires ive always had backfires with my tbe but these ones are weird i get the downshift backfires but now when i cometo a complete stop just as the revs go to idle or back into closed loop it does a loud pop it doesnt happen everytime but most of the time i like bacfires but just this one is weird also when i change gears up it backfirs louder i am running a 50/50 bov but once again this problem only occurd after the decap

    maf has been scaled via rom raider tool other than these problems car is running fine with decaps wot is good but my tune is sloppy i got my tune from infoumas tune but i worked on it as i did the decaps after the e tune things i changed

    injector scailing and cc
    afr's to correct ratio's running 10.8 during spool and 11.0 at redline but during spool its abit richer sometimes need to fine tune and my boost problem fixed :/ (boost comes on late
    maf scailing for aps 65mm intake and the injectors

    everything elese he has done but with this map the car doesnt pull hard as it use to with a custom map i made but that custom map i made had alot of knock so i took it off im getting no knock with this map but the timing is not much diffrent from stock :/

    i have been driving with these problems for a while but its getting annoying now help would be great

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  3. #2
    Master Baiter EJ257's Avatar
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    You mentioned that you decapped the injectors; did you get them flowtested?
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    Moderator Donkey's Avatar
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    car very hard to start and bad tune??

    You probably need to change the injector latency. Hopefully you were not trying to scale the MAF and injectors at the same time. If you don't know what your doing it will cause you to chase your tail.
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  5. #4
    Registered User sxcrxy's Avatar
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    I dudnt have time to flow teest them as i did the decqps onva sunday no were was open and i needed the car andbflow test is only telling me how much each injector puts out so it shouldnt have effect with thesebproblems like i said wot is fine everything runs well and donkey my injector scqiling is 799.97 and i scaled the maf after but does the same problems with stock maf

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    Moderator Donkey's Avatar
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    Not all decapped injectors flow the same. Thats the point of getting them flow tested. Witch hunter.com will actually flow test and get you a balnced set by using what they have in stock. Some people have used as little as 750cc to get the injectors to work and some as much as 850cc. I did a set and had almost 25-50cc difference between injectors.
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  7. #6
    Master Baiter EJ257's Avatar
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    Quote Originally Posted by Donkey
    Not all decapped injectors flow the same. Thats the point of getting them flow tested. Witch hunter.com will actually flow test and get you a balnced set by using what they have in stock. Some people have used as little as 750cc to get the injectors to work and some as much as 850cc. I did a set and had almost 25-50cc difference between injectors.
    But Ron, mismatched flow has nothing to do with his issue
    2005 WRX STi (Mods | Virtual Dyno)

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  8. #7
    Registered User sxcrxy's Avatar
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    Quote Originally Posted by EJ257 View Post
    But Ron, mismatched flow has nothing to do with his issue
    lololol no guys dont get me wrong i mean as in i thought that was only telling the limit of the injectors so it would only matter for top end so your saying thats its my injector sailing if i get them flow tested what do i do after to fix the starting problem thats my main one

    ej257 i now you know more than me hence why im here asking for help but just wanna know how it would affect it? if the saciling was wrong the car would run bad all the time not just be hard to start right?

  9. #8
    Moderator Donkey's Avatar
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    Like I said,you also have to adjust the injector latency not just the scaling. But it could be a combination of things. I personally don't use the Romraider scaler. Most people when they do use it,are using it incorrectly. So how did you scale the WOT portion of the MAF scaling?
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  10. #9
    Registered User sxcrxy's Avatar
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    Quote Originally Posted by Donkey View Post
    Like I said,you also have to adjust the injector latency not just the scaling. But it could be a combination of things. I personally don't use the Romraider scaler. Most people when they do use it,are using it incorrectly. So how did you scale the WOT portion of the MAF scaling?
    well i didnt the wot part is still stock i only did 1.1 - 2.9v using the maf scaling

  11. #10
    Registered User sxcrxy's Avatar
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    Quote Originally Posted by Donkey View Post
    Like I said,you also have to adjust the injector latency not just the scaling. But it could be a combination of things. I personally don't use the Romraider scaler. Most people when they do use it,are using it incorrectly. So how did you scale the WOT portion of the MAF scaling?
    turns out all my problems were my intial ecu raw value was at 12 changed it to 16 bam everything was sweet :P and i retuned my WHOLE maf scailing my afrs looking good you leanr alot over time with the internet :P thanks guys

  12. #11
    Moderator Donkey's Avatar
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    Quote Originally Posted by sxcrxy View Post
    turns out all my problems were my intial ecu raw value was at 12 changed it to 16 bam everything was sweet
    That would actually have nothing to do with your problem. The default from the factory is 8. After 1-2 WOT pulls it would be at 16 again if everything was fine (no knock).
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  13. #12
    Registered User sxcrxy's Avatar
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    Quote Originally Posted by Donkey View Post
    That would actually have nothing to do with your problem. The default from the factory is 8. After 1-2 WOT pulls it would be at 16 again if everything was fine (no knock).
    I didnt think so too but it always stayed on 12 so i had a look on my tune and for some reason it was set 12 so i put it to 16 it kicked over first go ? All the time now so it must of been that

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