Code P0171 and P0172 on Boosted NA-T? Help!
02-06-15, 04:52 PM
#1
Code P0171 and P0172 on Boosted NA-T? Help!
Hey guys, I am having trouble getting my boosted 1998 SC300 to run right. After disconnecting the battery, my SC will run perfect for a couple days, then it will start sputtering and running really rough especially while at cruise with partial throttle (no boost).
After this happens, my scanner reveals 2 pending codes: P0171 and P0172 which means system is running too rich and too lean.
Here are the basic specs:
-Stock 2JZGE engine with NA-T 70mm turbo
- AEM FIC 6 (already tuned by professional tuner)
-550cc injectors and Supra TT fuel pump
-all o2 sensors connected to downpipe (I have 02 sensor spacers on both bank 2 sensors)
-MAF is welded to charge pipe (same location as stock)
So has anyone with a boosted OBD2 engine have this problem with P0171 and P0172 codes? Thanks!
After this happens, my scanner reveals 2 pending codes: P0171 and P0172 which means system is running too rich and too lean.
Here are the basic specs:
-Stock 2JZGE engine with NA-T 70mm turbo
- AEM FIC 6 (already tuned by professional tuner)
-550cc injectors and Supra TT fuel pump
-all o2 sensors connected to downpipe (I have 02 sensor spacers on both bank 2 sensors)
-MAF is welded to charge pipe (same location as stock)
So has anyone with a boosted OBD2 engine have this problem with P0171 and P0172 codes? Thanks!
02-08-15, 09:18 PM
#5
I think you are absolutely right, Today, I finally reviewed my tune file and noticed my MAF voltage was not clamped! All of the values on the table are set to "0". I think that once the ECU is past it's learning mode (after resetting ECU), the MAF goes crazy and A/F ratios are being changed by the ECU and AEM at the same time...
02-11-15, 04:06 AM
#6
First off I would like to say I have no experience with this system, but have done plenty of reading about it.
Your car should be a vvti 2jz which is good news because the is300 guys have gone through a lot of this already.
Go here for some info on the set up > http://my.is/forums/f114/aem-fic-tun...363846?page=12
From my readings you keep b1s1 and remove b2s1. Splice b1s1 signal to b2s1 for the stock ecu. This syncs both o2 sensors together and makes the stock ecu happy as both banks will have the same a/f ratio. Figuring out the heater circuits is another story to keep the CEL away. Token solutions may have came up with something for the heater circuit but I can't say 100%.
Also the MAF sensor must be clamped at some point. That site suggests 4.7v but everyone's car is a little different. You're supposed to test it first while still stock to see what your maximum voltage reading is then clamp it there. The more the work MAF sensor does the easier it is on you. But this should only affect boosted driving though.
I suggest doing some reading and searching for is300 as they have used this system much more than the sc crowd.
Having an obd2 scanner and wide band o2 are a must for this set up.
Again not saying I know this will fix you problem because I don't have any personal experience. I can only repost what I've read. Hopefully this leads you on the right direction.
Good luck
Your car should be a vvti 2jz which is good news because the is300 guys have gone through a lot of this already.
Go here for some info on the set up > http://my.is/forums/f114/aem-fic-tun...363846?page=12
From my readings you keep b1s1 and remove b2s1. Splice b1s1 signal to b2s1 for the stock ecu. This syncs both o2 sensors together and makes the stock ecu happy as both banks will have the same a/f ratio. Figuring out the heater circuits is another story to keep the CEL away. Token solutions may have came up with something for the heater circuit but I can't say 100%.
Also the MAF sensor must be clamped at some point. That site suggests 4.7v but everyone's car is a little different. You're supposed to test it first while still stock to see what your maximum voltage reading is then clamp it there. The more the work MAF sensor does the easier it is on you. But this should only affect boosted driving though.
I suggest doing some reading and searching for is300 as they have used this system much more than the sc crowd.
Having an obd2 scanner and wide band o2 are a must for this set up.
Again not saying I know this will fix you problem because I don't have any personal experience. I can only repost what I've read. Hopefully this leads you on the right direction.
Good luck
Last edited by Bflatsharp; 02-11-15 at 06:28 AM.
02-12-15, 05:42 PM
#7
First off I would like to say I have no experience with this system, but have done plenty of reading about it.
Your car should be a vvti 2jz which is good news because the is300 guys have gone through a lot of this already.
Go here for some info on the set up > http://my.is/forums/f114/aem-fic-tun...363846?page=12
From my readings you keep b1s1 and remove b2s1. Splice b1s1 signal to b2s1 for the stock ecu. This syncs both o2 sensors together and makes the stock ecu happy as both banks will have the same a/f ratio. Figuring out the heater circuits is another story to keep the CEL away. Token solutions may have came up with something for the heater circuit but I can't say 100%.
Also the MAF sensor must be clamped at some point. That site suggests 4.7v but everyone's car is a little different. You're supposed to test it first while still stock to see what your maximum voltage reading is then clamp it there. The more the work MAF sensor does the easier it is on you. But this should only affect boosted driving though.
I suggest doing some reading and searching for is300 as they have used this system much more than the sc crowd.
Having an obd2 scanner and wide band o2 are a must for this set up.
Again not saying I know this will fix you problem because I don't have any personal experience. I can only repost what I've read. Hopefully this leads you on the right direction.
Good luck
Your car should be a vvti 2jz which is good news because the is300 guys have gone through a lot of this already.
Go here for some info on the set up > http://my.is/forums/f114/aem-fic-tun...363846?page=12
From my readings you keep b1s1 and remove b2s1. Splice b1s1 signal to b2s1 for the stock ecu. This syncs both o2 sensors together and makes the stock ecu happy as both banks will have the same a/f ratio. Figuring out the heater circuits is another story to keep the CEL away. Token solutions may have came up with something for the heater circuit but I can't say 100%.
Also the MAF sensor must be clamped at some point. That site suggests 4.7v but everyone's car is a little different. You're supposed to test it first while still stock to see what your maximum voltage reading is then clamp it there. The more the work MAF sensor does the easier it is on you. But this should only affect boosted driving though.
I suggest doing some reading and searching for is300 as they have used this system much more than the sc crowd.
Having an obd2 scanner and wide band o2 are a must for this set up.
Again not saying I know this will fix you problem because I don't have any personal experience. I can only repost what I've read. Hopefully this leads you on the right direction.
Good luck
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07-08-15, 05:42 PM
#10
Help! I am still having this problem. I can't really drive my SC anymore. I connected the signal wire for B2S1 into B1S1 like the IS guy to trick the ECU into thinking both 02 sensors are outputting the same signal and still have the problem. I took my car to my tuner and they could not figure out the problem and saying it's not the tune.
07-09-15, 09:23 AM
#11
how do they have the fic wired. is it in intercept mode or is it just messing with the maf signal.
I think its not setup right and maybe you should find somewhere more familiar with it, or get familiar with it yourself.
having a touchy obd2 ecu you probably want it fully setup in intercept mode where its wired to the injectors and fooling the o2 sensors.
also it should be setup to fool the stock o2 sensors into thinking everything is right, hence keeping a zero trim.
normally the main 2 stock o2 sensors are removed (the ones that actually do fuel correction), and then the aem fic outputs a simulation to the stock ecu of an o2 sensor to trick it like above, and lastly to actually have an o2 adjusting something the aem fic should have its own wideband that it uses for fuel correction.
also the o2 spacers on the o2 sensors, you should only have those on the post cat sensors, definitely do not want those on the main ones.
I think its not setup right and maybe you should find somewhere more familiar with it, or get familiar with it yourself.
having a touchy obd2 ecu you probably want it fully setup in intercept mode where its wired to the injectors and fooling the o2 sensors.
also it should be setup to fool the stock o2 sensors into thinking everything is right, hence keeping a zero trim.
normally the main 2 stock o2 sensors are removed (the ones that actually do fuel correction), and then the aem fic outputs a simulation to the stock ecu of an o2 sensor to trick it like above, and lastly to actually have an o2 adjusting something the aem fic should have its own wideband that it uses for fuel correction.
also the o2 spacers on the o2 sensors, you should only have those on the post cat sensors, definitely do not want those on the main ones.
Last edited by Ali SC3; 07-09-15 at 09:29 AM.
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