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Old 11-11-2014, 12:50 PM   #5
Ultramaroon
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Join Date: Sep 2014
Drives: a 13 e8h frs
Location: vantucky, wa
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Quote:
Originally Posted by VitViper View Post
I have seen this behavior on other platforms with upgraded (larger than stock) injectors. Typically it's because of some vapor lock combined with imperfect hot cranking injector PW. You can generally tune it out, but sometimes it turns into quite the battle as there's literally a very small window (very tight inj pw window) that is a "sweet spot".

Seems this behavior is also really common on returnless fuel systems. Every time I've converted a car to return style, the problem goes away (my theory is that since the fuel pressure has a way to drain back into the tank, it won't ever dribble out of the PI injectors -- which I believe is what really causes the issue, the fuel may be dribbling out a little and just vaporizing in the IM).
The fuel boils a little bit "somewhere" in the rail/line and, in a returnless system, that bubble has nowhere to go. If a port injector ever dribbles it's time to replace it. Makes sense in this car because it gets friggin HOT under the hood.
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