yoda598 Posted September 22, 2020 Share Posted September 22, 2020 hey guys, im having an issue on start up where the car will idle perfectly at 14.7-14.8 on the wideband but when closed loop kicks in it shoots to rich!! like 10.0+rich, you can watch the ltft and stft start adding fuel. but if you drive before it does it (30 seconds maybe) its fine. when you stop and check fuel trims the theyre perfect. maybe 1% or so at idle. its driving me mad!!! Quote Link to comment Share on other sites More sharing options...
Roland@pcmtec Posted September 23, 2020 Share Posted September 23, 2020 Is the sensor dead? Is your injector trims within 3% when warm at cruise and idle? Do you have a large dump pipe? Assuming the sensor isn't dead and you have an aftermarket dump pipe this is not uncommon. A simple work around is to increase the closed loop delay when cold to 2 minutes. This assumes your injector scalars are within a few percent when warm, injector scaling that is up the creek will do things like this as well. Quote Link to comment Share on other sites More sharing options...
yoda598 Posted September 23, 2020 Author Share Posted September 23, 2020 16 minutes ago, Roland@pcmtec said: Is the sensor dead? Is your injector trims within 3% when warm at cruise and idle? Do you have a large dump pipe? Assuming the sensor isn't dead and you have an aftermarket dump pipe this is not uncommon. A simple work around is to increase the closed loop delay when cold to 2 minutes. This assumes your injector scalars are within a few percent when warm, injector scaling that is up the creek will do things like this as well. I do have a 4" dump! Sensor seems good, not too old as far as I know. I'll replace it soon just incase. Injector trims are pretty spot on. I'll give it a go and let you know the outcome. Quote Link to comment Share on other sites More sharing options...
Roland@pcmtec Posted September 23, 2020 Share Posted September 23, 2020 Sensor is probably further away from the stock position I'm guessing so it is taking longer to heat up. I would simply increase the closed loop delay when cold until the problem goes away. Quote Link to comment Share on other sites More sharing options...
yoda598 Posted September 23, 2020 Author Share Posted September 23, 2020 ive adjusted auF0162 but its still going into closed loop after 30secs or so. im guessing ive missed another one somewhere Quote Link to comment Share on other sites More sharing options...
Roland@pcmtec Posted September 23, 2020 Share Posted September 23, 2020 Can you datalog wrmego. If it is set to 1 it is considered "warm" and will start trimming. There are a few other conditions that can enable it other than auF0162 but these should not kick in until at least 255 seconds has elapsed. Quote Link to comment Share on other sites More sharing options...
yoda598 Posted September 23, 2020 Author Share Posted September 23, 2020 does auF0163 relate to the 02 sensor being up to temp to begin trimming? Quote Link to comment Share on other sites More sharing options...
yoda598 Posted September 23, 2020 Author Share Posted September 23, 2020 got it delay, even after the 2 minutes it still pegs rich if left idling :-/ Quote Link to comment Share on other sites More sharing options...
Roland@pcmtec Posted September 23, 2020 Share Posted September 23, 2020 Do you trust your wideband? What does the narrowband mv say when you datalog it? You can get a pretty good estimate of AFR from the mv reading. 850-900mv would be very rich for example. Quote Link to comment Share on other sites More sharing options...
yoda598 Posted September 23, 2020 Author Share Posted September 23, 2020 widebands brand new, goes rich enough to pump black smoke and missfire badly. Quote Link to comment Share on other sites More sharing options...
yoda598 Posted September 23, 2020 Author Share Posted September 23, 2020 even with ltft so it cant learn under 0.3 load the stft starts adding 30+.. Quote Link to comment Share on other sites More sharing options...
Roland@pcmtec Posted September 23, 2020 Share Posted September 23, 2020 Can you datalog the narrowband, sounds like it is faulty. To disable closed loop O2 follow this guide: 1 Quote Link to comment Share on other sites More sharing options...
Puffwagon Posted September 23, 2020 Share Posted September 23, 2020 I've had this exact issue with the trims intermittently adding fuel at startup and also the needing to rev or drive it after it started, to fix the issue. Turns out I had melted narrow band wiring from a 4 inch dump install. I did replace the NB sensor with another second hand unit as part of the diagnosing process so that may have had something to do with it. Quote Link to comment Share on other sites More sharing options...
yoda598 Posted September 23, 2020 Author Share Posted September 23, 2020 @Puffwagon i could kiss you! replaced NB with spare and its perfect!! no melted wires but mustve been damaged in some way!! funny, it looks almost.... oh well fixed!! @Roland@pcmtecthanks for the help! 1 Quote Link to comment Share on other sites More sharing options...
Puffwagon Posted September 23, 2020 Share Posted September 23, 2020 Haha I'm glad it's sorted. It happened a number of years ago so I didn't even think to mention my experience, until Rolls brought up the faulty NB. Quote Link to comment Share on other sites More sharing options...
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