P0171 - again and getting more frequent
- Thread starter Spamby
- Start date
Spamby
Meat Product Toy
Glad you got it all figured out.
I'm very ecstatic about this. This thing has been driving me bonkers for the last month.
I have also learned a huge amount about data logging and interpreting them.
A headache this has been but also a very positive learning experience.
???? I'm not seeing how adding hose does anything. Can you explain?
Spamby
Meat Product Toy
Well, the GR has a funky fuel delivery system. All sorts of crazy crap under the hood in the realm of hoses and dampers. Apparently, the fuel lines experience some kind of pressure wave resulting in the very brief millisecond of fuel starvation or just not smooth fuel delivery. Water hammering, like the pipes in your house.
This happens between 2000 ish and 3000 rpms. You can feel it and now obviously, you can see it in datalogs. For a brief period, during these rpm's, the fuel injectors are intermittently starved for fuel, you have too much air in there and not enough fuel. The front AFR sensor says holy sheet there is too much air and then tries to correct by dumping more fuel and then once 14.7 has been reached again, pulls fuel. This process repeats until that magical rpm area is exceeded or reduced. BAsically, it looks like a bipolar engine off of its meds. lol
For whatever reason, the extra length of hose absorbs this resonance, if you will, and helps the fuel delivery pulses become more smooth or even. I have seen people add inline filters and/or another damper with successful results.
I have felt this on the stock map. I have felt this on OTS maps. I did not feel this until this summer on my Protune. Atmospheric conditions can also play a factor.. obviously.
The extra hose does not totally correct this, some work with a tuner is needed to further smooth this out. But it substantially reduces it to unnoticeable or almost.
It's an f-ed up deal that I have read about over the years. Once I started to become better at reading datalogs, researched the living hell out of this scenario and put two and two together, the light came on. It cost me 8 dollars to find out.
This happens between 2000 ish and 3000 rpms. You can feel it and now obviously, you can see it in datalogs. For a brief period, during these rpm's, the fuel injectors are intermittently starved for fuel, you have too much air in there and not enough fuel. The front AFR sensor says holy sheet there is too much air and then tries to correct by dumping more fuel and then once 14.7 has been reached again, pulls fuel. This process repeats until that magical rpm area is exceeded or reduced. BAsically, it looks like a bipolar engine off of its meds. lol
For whatever reason, the extra length of hose absorbs this resonance, if you will, and helps the fuel delivery pulses become more smooth or even. I have seen people add inline filters and/or another damper with successful results.
I have felt this on the stock map. I have felt this on OTS maps. I did not feel this until this summer on my Protune. Atmospheric conditions can also play a factor.. obviously.
The extra hose does not totally correct this, some work with a tuner is needed to further smooth this out. But it substantially reduces it to unnoticeable or almost.
It's an f-ed up deal that I have read about over the years. Once I started to become better at reading datalogs, researched the living hell out of this scenario and put two and two together, the light came on. It cost me 8 dollars to find out.
Similar threads
