What would cause high injector DC?
02-23-2011, 09:50 AM
#1
What would cause high injector DC? Car in sig. ~360rwhp on 98 injectors (28#). Walbro pump. 58-60# fuel pressure.
At 6200-6300rpm EFI live is showing my duty cycle to be 94-96%. The car was dyno tuned to 12.8-13.2 a/f ratio.
Tuners first pull was putting the car in the 14s on a/f before he stopped and richened it.
What would cause such high duty cycle at this low power level? Ive been suspecting a vacuum leak and searching for one with no luck. But if I have one, it was tuned over. The car runs very well other than occasional idle surging coming to stops and occasional moments of high idle...then it comes down.
Of course these could also be just minor tuning things, it's the high DC that is making me scratch my head.
At 6200-6300rpm EFI live is showing my duty cycle to be 94-96%. The car was dyno tuned to 12.8-13.2 a/f ratio.
Tuners first pull was putting the car in the 14s on a/f before he stopped and richened it.
What would cause such high duty cycle at this low power level? Ive been suspecting a vacuum leak and searching for one with no luck. But if I have one, it was tuned over. The car runs very well other than occasional idle surging coming to stops and occasional moments of high idle...then it comes down.
Of course these could also be just minor tuning things, it's the high DC that is making me scratch my head.
02-23-2011, 12:15 PM
#3
it just means your car isn't very efficient at turning petrol into power. look up Brake Specific Fuel Consumption, it's some interesting reading.
in other news, if your car randomly surges at power so mild, you tune sucks. Start tuning yourself, software will help you chase down leaks.
in other news, if your car randomly surges at power so mild, you tune sucks. Start tuning yourself, software will help you chase down leaks.
02-24-2011, 03:29 AM
#5
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Car in sig. ~360rwhp on 98 injectors (28#). Walbro pump. 58-60# fuel pressure.
At 6200-6300rpm EFI live is showing my duty cycle to be 94-96%. The car was dyno tuned to 12.8-13.2 a/f ratio................Of course these could also be just minor tuning things, it's the high DC that is making me scratch my head.
At 6200-6300rpm EFI live is showing my duty cycle to be 94-96%. The car was dyno tuned to 12.8-13.2 a/f ratio................Of course these could also be just minor tuning things, it's the high DC that is making me scratch my head.
See thread here for your interest..
https://ls1tech.com/forums/pcm-diagn...-wideband.html
02-24-2011, 08:50 AM
#6
Thanks guys, bigger injectors will be put on the car eventually...but I'm waiting for the 799 heads and new cam because I don't want to keep paying for tunes or driving 4 hours to my old tuner.
I'm just wondering why about 98% of the cam only cars on this site are perfectly fine with below 90% DC making near 400rwhp and my lousy 360rwhp is sending them into the 90s.
I'm just wondering why about 98% of the cam only cars on this site are perfectly fine with below 90% DC making near 400rwhp and my lousy 360rwhp is sending them into the 90s.
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02-24-2011, 01:07 PM
#8
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this is very true. My old head cam setup on my 402 was close to being out of injector. I put on a set of mamo afrs and a lot better cam, and my duty cycle dropped, same injectors. I was thinking I was going to have to upgrade, but didnt have the money right after the heads so i figured I would start tuning with what i had. Needless to say I was happy.
