Thread: FI turbo issues
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Old 04-11-2014, 01:31 PM   #24
nelsmar
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I have been avoiding getting involved until now but... Since the OP is beating around the bush:

Quote:
Originally Posted by JDLAutoDesign View Post
The new location of the bov should have no effect on skewing maf readings. I think we need more tuner input honestly

To the OP: You know you could just do what everyone has told you and moved on with the tuner filling your head with false info.



If you note here you will see his car picking up negative fuel trims while in mixed injection mode. But once it goes port only (this is a very short period of time) you can see the fuel trims retracting. And during this time the AFR is just shifting lean and the engine is shutting off. This is a direct cause of issue from port injector latency mis-calibration. What is going on is the ecu is opening the injectors for what it expects is x# of ms, but due to latency of opening time it is not actually opening the duration it requested. The issue was in the 6g/s learning window. Which is why it was not affecting all other areas as that window would shift between DI and DI + Port from time to time. The reason you didn't have this issue with the first flash from your tuner is because he was maxing out the fuel trim on the rich scale. You were running well below 11AFR and so when the ecu attempted to pull fueling it was maxing out the short term trims (since your tuner doesn't use long term trims) and the ecu was not allowed to pull any more fueling out. This would run a longer than desired injector port time which was actually closer to correct due to the fact the latencies are set to a smaller value than they should be. If you still want to beat around the bush go install your stock injectors and see what happens. Hell a stock rom would probably even work considering the maf size for a simple throttle blip as it would have long term trims, and much better port latency times.

Sure the MAF can be skewed with the blow off valve but there are a number of resolutions to that such as hacking the MAF table, speed density, adjusting overrun MAF, custom tables based off misc inputs. I tried to help you out in person at JDL and told you that it takes a bit to dial in injectors but yo insisted on using your current tuner. Here you are going in a full circle to find out you are having the same issue from the start: a tuner issue.
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