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Series I Engine Tuning Forum EMS (Flash Tuning, Interceptor, Piggy Back, Stand Alone)

Injector duty cycle Issues

Old Sep 18, 2012 | 01:00 PM
  #26  
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Intake Vacuum Leak Physical Check

This is way old school, but if you partially block the air intake at idle and RPMs increase, rather than drop, then there definitely is a vacuum leak. Have you tried that?

Last edited by MPG > HP; Sep 18, 2012 at 01:04 PM.
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Old Sep 18, 2012 | 05:52 PM
  #27  
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Originally Posted by HiFlite999
Where does calcLoad come from? It's a calculation. I don't see any obvious way to get that without MAF as an input parameter.
My point was merely that VE is the highest level correction applied to fuel flow. Once the ECU gets to it everything else has been worked out, including calculating load
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Old Sep 18, 2012 | 06:18 PM
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we have a 2 speed fuel pump??
Does that factor in?
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Old Sep 18, 2012 | 06:44 PM
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I've always heard it referred to as a static pressure fuel pump as far as the injectors and latency are concerned, OD.
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Old Sep 18, 2012 | 07:29 PM
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Originally Posted by MPG > HP
This is way old school, but if you partially block the air intake at idle and RPMs increase, rather than drop, then there definitely is a vacuum leak. Have you tried that?


I think you posted in the wrong thread
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Old Sep 20, 2012 | 09:48 PM
  #31  
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Originally Posted by shadycrew31
It appears the issues pops up when the calculated load hits 60 and above. Once it drops below 60 the injectors pop back on.

You can see it more clearly with this edited copy my friend made me.
Just got around to opening the first log on my laptop and I picked it up on Accel. Position first, once you went higher than 23% it was heading lean and didn't come back until you backed of the gas pedal slightly. Then the vehicle speed was not changing much and the Calc. Load told the tale.

I personally would try addressing this in the fuel table first (7500 rpm/0.6 Load/3rd gear map). Messing with the VE map effects a number of other variables. Ultimately the P2s may not match up with the OE NA transition programming

Last edited by TeamRX8; Sep 20, 2012 at 09:50 PM.
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Old Sep 22, 2012 | 09:16 AM
  #32  
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at 60% load and or a certain % of throttle position the fuel pump voltage changes.
I would think that you may want to check the fuel pressures during these periods. It is just another metric you want to eliminate before you start chasing tuning.
The fpr is supposed to supply a constant pressure--very true. But you never know and it is a variable that could have this type of affect. Especially when you are such a high rpm and only using very light throttle.
It probably is NOT Fp related---but it could be.
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Old Sep 22, 2012 | 09:41 AM
  #33  
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It would increase flow/pressure at the change. The opposite is happening in this case (going dramatically lean with slightly higher load). Your technical expertise is in it's usual form; fubar.
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Old Sep 22, 2012 | 01:28 PM
  #34  
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you are thinking in one dimension.
If the fuel pump is switching from low to high speed,or high speed to low speed functioning it is possible to have fluctuating fuel pressures. If that is happening then the the a/f's theoretically could be bouncing around.
It would be interesting to do primary testing of the fuel delivery system constancy during the milliseconds that are being questioned.
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Old Sep 22, 2012 | 03:18 PM
  #35  
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... or just put a fuel pressure gauge on it and make sure it's a steady 59 psi.
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Old Sep 22, 2012 | 08:10 PM
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you could never work for the government--lol.
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Old Sep 22, 2012 | 08:39 PM
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I actually did for a while... not sure how that applies here... suspect you're referring to our government's stellar track record for efficiency.
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Old Sep 23, 2012 | 08:34 PM
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Lol--what I meant is you got to the point in a simple manner. If you worked for the government--then you know that would never be their way.
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Old Sep 23, 2012 | 08:45 PM
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yup... I'm with ya
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