jubs Posted April 8, 2020 Report Share Posted April 8, 2020 Hi, need some more help with the next issue please. Car starts and idles, can run auto tune and get it operating at Lambda. problem is when I try and rev the engine ( especially when at operating temp ) as soon as the throttle opens it goes mega lean and stalls, how do I set up the fuelling and or settings to deal with aggressive ITB`s ? Have attached the current tune and a log file - the log file is of the engine at correct temp and at idle, runs for about 10 seconds and then I open the throttle about 3 degrees and immediately stalls. FYI - If I pump the throttle when at idle I can sometimes get it to rev but not for long before stalling FYI setup info BMW N45B20 running Link Fury ECU 4 Cylinder Wideband Lambda sensor installed Direct coil on plug Standard CAM`s Vanos Inlet and exhaust ( cam sensors on both cams ) - disconnected for now Home made ITB - taken from BMW M3 ( with cylinder 5 and 6 removed ) with TP setup Returnless fuel system ( 3.5 bar operating pressure ) Injectors from BMW 320si ( N45B20 ) tech spec unknown ( VDO part number A2C59506218 ) Idle value idle control from a BMW M40 (disconnected/blocked for now until I get the engine running stable) No MAP sensor Thanks John cutting out with opening throttle.llg G4+ Fuy JB1 test v2.pclr Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 8, 2020 Report Share Posted April 8, 2020 Your fuel table set up with 10% breakpoints is not really suitable for ITB's. Because you get a large increase in airflow for the first few percent of throttle opening you need much finer breakpoints at small throttle openings. Once your past about 20% open then your breakpoint increments can get bigger and bigger. Below is an example from one of my ITB engines, do your breakpoints similar to this. Notice at 1000RPM how much difference in fuel there is between 0% and 2% throttle... Also notice at say 3000RPM how little difference there is in fuel between say 40% and 100% throttle. Also, you will need to add a map sensor later if you want to use idle air control, without it the ecu wont be able to compensate for the extra air that the idle valve lets through. Quote Link to comment Share on other sites More sharing options...
Aaron Johnson Posted February 4, 2022 Report Share Posted February 4, 2022 Thank you Adam! i would like to see the rest of this map as it changes with higher rpm vs TPS. Quote Link to comment Share on other sites More sharing options...
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