Please help with out-of-boost lean condition...
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Joined: Nov 2009
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From: McKinney, TX
Few things, firstly how is your o2 sensor and does your system affect when you go into open loop?
I'm not convinced as said above about not being able to cope with mods and stock ecu there is of course an easy way to check look at your ltft and stft they have a min/max range of -/+ 30%
I'm not convinced as said above about not being able to cope with mods and stock ecu there is of course an easy way to check look at your ltft and stft they have a min/max range of -/+ 30%
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Joined: Jan 2011
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IMO its the Synapse missing link. I have the same issue every now and then and I'm 100% convinced its from the missing link. Idles fine, pulls fine, boosts fine, highway cruses fine, but in that 35-50 MPH range in 4th/5th under light acceleration its like the car hiccups and the AFR's go lean and you get no acceleration. If you push the pedal in a bit more it kicks back into normal mode, AFR's go back to normal and the car starts accelerating.
Its like the Synapse missing link can't pick up on the very slight change in pressure within the throttle body in those light acceleration scenarios. There's not enough air flowing through the throttle body to make the MAP sensor see a difference due to the Synapse missing line between between the two... until you open the TB a little more by pressing the pedal down and then the MAP's like "oh, you're trying to accelerate" and then it gets back to normal. Its like at that light acceleration point the MAP just kinda spaces out for a few seconds or gets confused until you jar it awake with a push of the gas pedal.
I know exactly what you're talking about, and I've come to the conclusion that its the Synapse missing link.
Take the missing link off and just put the MAP back onto the throttle body and drive out of boost for a few miles. See if you can replicate the issue with light acceleration at lower speeds (35-50 MPH) without the missing link on there. I bet you won't be able to replicate it without the missing link.
BTW - has anyone told you this isn't the best setup for a turbo car?
Its like the Synapse missing link can't pick up on the very slight change in pressure within the throttle body in those light acceleration scenarios. There's not enough air flowing through the throttle body to make the MAP sensor see a difference due to the Synapse missing line between between the two... until you open the TB a little more by pressing the pedal down and then the MAP's like "oh, you're trying to accelerate" and then it gets back to normal. Its like at that light acceleration point the MAP just kinda spaces out for a few seconds or gets confused until you jar it awake with a push of the gas pedal.
I know exactly what you're talking about, and I've come to the conclusion that its the Synapse missing link.
Take the missing link off and just put the MAP back onto the throttle body and drive out of boost for a few miles. See if you can replicate the issue with light acceleration at lower speeds (35-50 MPH) without the missing link on there. I bet you won't be able to replicate it without the missing link.
BTW - has anyone told you this isn't the best setup for a turbo car?
Joined: Jan 2006
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From: location, location
Originally Posted by s2konroids' timestamp='1371137794' post='22606138
Few things, firstly how is your o2 sensor and does your system affect when you go into open loop?
I'm not convinced as said above about not being able to cope with mods and stock ecu there is of course an easy way to check look at your ltft and stft they have a min/max range of -/+ 30%
I'm not convinced as said above about not being able to cope with mods and stock ecu there is of course an easy way to check look at your ltft and stft they have a min/max range of -/+ 30%
Joined: Jan 2006
Posts: 20,788
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From: location, location
Fwiw it's worth in my earlier low boost Comptech SC days I ran a missing link map fix and rrfpr.
Never had any problems, however this really is a bad aid fix.
If you don't want to spend loads of gemu will be all you need I ran that setup fir years.
Never had any problems, however this really is a bad aid fix.
If you don't want to spend loads of gemu will be all you need I ran that setup fir years.
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Joined: Jun 2007
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If it proves to be an issue with the missing link ( which is entirely possible) The Comptech supplied ESM aka- Electronic Signal Modifier) is an alternative that works flawlessly, the drawback is you have to splice into your engine harness, but is stupid reliable compared to the hit and miss of the mechanical missing link.
Also as mentioned before, the rising rate fuel pressure regulators that come with the VT/CT SC kits are calibrated to run with the boost character of an SC, which also happens to be much more predictable to tune a fuel curve to compared to a turbo, therefore success of these units on a SC should not be compared to running one on a turbo car (S2konroids)
And though I’m a big supporter of the E-manage Ult myself with NA and SC cars, I don’t think I would be comfortable with one on a Turbo car. Turbo is completely different. There is nothing OEM that translates or transferable. So asking the Emanage to essentially start from scratch is asking for headaches and guesswork. On a SC set up, its more inline with the factory power curve - an extension of NA. Easy and intuitive tune around using the OEM tune as a solid foundation to work from.
Also as mentioned before, the rising rate fuel pressure regulators that come with the VT/CT SC kits are calibrated to run with the boost character of an SC, which also happens to be much more predictable to tune a fuel curve to compared to a turbo, therefore success of these units on a SC should not be compared to running one on a turbo car (S2konroids)
And though I’m a big supporter of the E-manage Ult myself with NA and SC cars, I don’t think I would be comfortable with one on a Turbo car. Turbo is completely different. There is nothing OEM that translates or transferable. So asking the Emanage to essentially start from scratch is asking for headaches and guesswork. On a SC set up, its more inline with the factory power curve - an extension of NA. Easy and intuitive tune around using the OEM tune as a solid foundation to work from.
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Joined: Jun 2010
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Thanks for the insight fellas! I wish I just had another s2k to swap the TB and MAF real quick to see if that's the culprit VS throwing money @ parts that would be better invested in EMS lol. May just wait till I get my EMS to go forward. I already have ID1000's, 10lb spring, and 3in down pipe. It's just a damn work in progress :/
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