AOS modification.
04-24-2019, 03:56 PM
#106
Rennlist Member
I get the overloaded thing. Sometimes life just keeps pouring it on. Hope you're feeling better and get some time to relax.... 
I doubt you are causing damage. And by this, I mean the car and the environment. You will be releasing small amounts of fuel vapor and crankcase vapors into the air. If you can't get your new AOS installed soon, you may want to try something similar to my temporary fix (125,000 mile thread). Don't sweat the little things.
I doubt you are causing damage. And by this, I mean the car and the environment. You will be releasing small amounts of fuel vapor and crankcase vapors into the air. If you can't get your new AOS installed soon, you may want to try something similar to my temporary fix (125,000 mile thread). Don't sweat the little things.
I also wanted to wait on hacking my AOS line until I replaced the AOS and was committed to the catch can.
04-25-2019, 01:58 PM
#108
Rennlist Member
04-26-2019, 12:23 PM
#110
Rennlist Member
Lol. yes it is. Just look for the key posters and skip the rest. Lots of very good information.
The kit was for the smaller Boxter motors and less than 20 units where made and sold from what it looks like with not much follow up.
Fuel trims seem to be the concern, but some have been successful...
The kit was for the smaller Boxter motors and less than 20 units where made and sold from what it looks like with not much follow up.
Fuel trims seem to be the concern, but some have been successful...
04-26-2019, 06:21 PM
#112
Certainly was an interesting thread which seemed to have hope of finding an alternative solution to replacing the AOS but unfortunately it didn't seem like this was a well proven solution. With mine being a daily driver, I have to bite the bullet and get the AOS replaced since my CEL is back on.
04-26-2019, 06:27 PM
#113
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Certainly was an interesting thread which seemed to have hope of finding an alternative solution to replacing the AOS but unfortunately it didn't seem like this was a well proven solution. With mine being a daily driver, I have to bite the bullet and get the AOS replaced since my CEL is back on.
04-26-2019, 09:25 PM
#114
Here is the diagnosis and was told the AOS needed to be replaced
"Has DME/engine control system codes 27 (cylinder 1-3, oxygen sensing range), 35 (cylinder 4/6, oxygen sensing range), P1124 (system too lean at idle, cyl 1-3) and P1126 (system too lean at idle, cyl 4- 6). Most likely the crankcase vent valve/air oil separator is bad (it is also leaking some oil). "
"Has DME/engine control system codes 27 (cylinder 1-3, oxygen sensing range), 35 (cylinder 4/6, oxygen sensing range), P1124 (system too lean at idle, cyl 1-3) and P1126 (system too lean at idle, cyl 4- 6). Most likely the crankcase vent valve/air oil separator is bad (it is also leaking some oil). "
05-02-2019, 05:43 AM
#116
Rennlist Member
This was not a fun project!
05-02-2019, 11:27 AM
#118
I am no fuel trim expert. But what I know is that:
RKAT is the adaptation value near idle. These number you want to be 0 or close to 0. In my case: 0,14% and 0,33% deviation, considered as 0.
FRA is the adaptation value under load and further divided into FRAU (lower load range / U = unter ) and FRAO (higher load range / O = oben) ranges. Ideally these values should be 1 or very close to 1. 0.95 till 1.05 is generally considered as ok
A value of 1.03 means the ECU is adapting injection timing 3% to inject more fuel to correct a lean condition. A value of 0.97 would mean the opposite.
RKAT is the adaptation value near idle. These number you want to be 0 or close to 0. In my case: 0,14% and 0,33% deviation, considered as 0.
FRA is the adaptation value under load and further divided into FRAU (lower load range / U = unter ) and FRAO (higher load range / O = oben) ranges. Ideally these values should be 1 or very close to 1. 0.95 till 1.05 is generally considered as ok
A value of 1.03 means the ECU is adapting injection timing 3% to inject more fuel to correct a lean condition. A value of 0.97 would mean the opposite.
05-02-2019, 11:43 AM
#119
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My assumption is that percentages should be small (which yours are) and the FRA numbers should be close to 1 (which yours are, also). Are my assumptions correct?
Finally the value 1 - is that the amount of "deviation" needed to maintain the stoichiometric ratio? I.e. 14.7:1 = 1?
Maybe there's a link that would explain how this works (specific to the Porsche system)? I have more questions - but I'd rather not expose my ignorance on the matter more than I have already...
Did a little searching: https://www.callasrennsport.com/blog...im-information
Last edited by Scott at Team Harco; 05-02-2019 at 01:03 PM.
05-02-2019, 01:46 PM
#120
rkat is idle trims
fra is low load trims
frao and frau will always read the same as fra unless in a turbo with wideband o2 sensors
the car does not trim at wot/open loop (no feedback from oem narrow-band o2 sensors to establish trims as ecu richens mixture when engine working hard)
for rkat, values are given as +/- % fuel added, and you will get cell at +/-4%
for fra, values are given as +/- fuel added from a baseline of 1, and you will get a cell outside of 0.7 to 1.32
your trims are fine
fra is low load trims
frao and frau will always read the same as fra unless in a turbo with wideband o2 sensors
the car does not trim at wot/open loop (no feedback from oem narrow-band o2 sensors to establish trims as ecu richens mixture when engine working hard)
for rkat, values are given as +/- % fuel added, and you will get cell at +/-4%
for fra, values are given as +/- fuel added from a baseline of 1, and you will get a cell outside of 0.7 to 1.32
your trims are fine