AEM F/IC writeup
- Thread starter Ricktalife
- Start date
I'll take those pistons and rods off your hands when you're ready. As for the fic, its a dud for now. too many issues bit hopefully thry get worked out soon because i want one. Must be nice having no emmissions testing
So a bit of bad news. I was successful in getting zero trims and nice'ish 10.5-12 AFR's in closed loop, and 11.5 all the way across from 4200 up to 7k. Car pulls strong and there is just a small dip in the transition I wasn't able to tune out. Driving around is just fine, but I did a few more experiments and found out something interesting.
If I shift at a point where I go from somewhere above 4200 to somewhere below 4200, I get a terrible bog, and corresponding 8.8 AFRs.
This is because I am going back into my closed loop zone where I have my O2 offset and required positive fuel trim but the car stays in open loop. It ignores my O2 and uses the super rich open loop table and then my FIC is adding fuel on top of that. The AEM doesn't know the PCM has switched to open loop mode, so it just blindly adds fuel, and in open loop there is no correction taking place.
I also noticed a drop in power when stepping on the gas in 5th on the highway after a few seconds of staying under 4200 rpms at full throttle. So I went back and logged this too. It appears if you have the accelerator down in any gear for longer than 3 seconds, it will go into open loop mode. I even tried it in 2nd which is what I did most of my tuning in since it doesn't take up too much asphalt. If I start at about 1.5k rpms and do a pull I can see the fuel spike about 3 seconds after I put my foot down which is still well before the normal 4200 rpm transition.
So you can't have your cake and eat it too. The close/open loop parameters are not anything that the AEM can predict, or any piggyback for that matter.
On a dyno, you usually do a 4th gear pull, so you should see about 3 seconds of closed loop operation before going to open loop. All the tuning is done in open loop. If you did the pull in 2nd gear or 1st, you'd have a completely different result until you hit 4200 rpms.
So yes the AEM is probably as good if not better than any other piggyback, but it is limited by the PCM. You can tune for before or after the closed loop transition, but if you try to tune for both, you can become super rich if you go to open loop before 4200 rpms. Unless someone knows a trick to put the PCM into open loop mode on command, I don't see how you can make a perfect, all scenario, tune.
Currently it is better than stock though. The hesitation is gone, I get a lot less lift throttle backfire up top, closed loop acceleration is much much better, and if I wanted to make more power, I can use the AEM to avoid fuel cut and retard timing if I start detonating with higher boost. So its not a failure, but it's not as capable as a standalone either.
If I shift at a point where I go from somewhere above 4200 to somewhere below 4200, I get a terrible bog, and corresponding 8.8 AFRs.
This is because I am going back into my closed loop zone where I have my O2 offset and required positive fuel trim but the car stays in open loop. It ignores my O2 and uses the super rich open loop table and then my FIC is adding fuel on top of that. The AEM doesn't know the PCM has switched to open loop mode, so it just blindly adds fuel, and in open loop there is no correction taking place.
I also noticed a drop in power when stepping on the gas in 5th on the highway after a few seconds of staying under 4200 rpms at full throttle. So I went back and logged this too. It appears if you have the accelerator down in any gear for longer than 3 seconds, it will go into open loop mode. I even tried it in 2nd which is what I did most of my tuning in since it doesn't take up too much asphalt. If I start at about 1.5k rpms and do a pull I can see the fuel spike about 3 seconds after I put my foot down which is still well before the normal 4200 rpm transition.
So you can't have your cake and eat it too. The close/open loop parameters are not anything that the AEM can predict, or any piggyback for that matter.
On a dyno, you usually do a 4th gear pull, so you should see about 3 seconds of closed loop operation before going to open loop. All the tuning is done in open loop. If you did the pull in 2nd gear or 1st, you'd have a completely different result until you hit 4200 rpms.
So yes the AEM is probably as good if not better than any other piggyback, but it is limited by the PCM. You can tune for before or after the closed loop transition, but if you try to tune for both, you can become super rich if you go to open loop before 4200 rpms. Unless someone knows a trick to put the PCM into open loop mode on command, I don't see how you can make a perfect, all scenario, tune.
Currently it is better than stock though. The hesitation is gone, I get a lot less lift throttle backfire up top, closed loop acceleration is much much better, and if I wanted to make more power, I can use the AEM to avoid fuel cut and retard timing if I start detonating with higher boost. So its not a failure, but it's not as capable as a standalone either.
Hmmm, Im sorry that its not working like you have planned, but Im glad you are the one doing the ground work because you sound more capable of understanding all of the issues. It seems that the stock ECU is clairvoyant and is somewhere in the 8th dimension. Oh well, still subbin for ideas and answers since i haven't settled on a standalone yet.......although i just got a lead on a Haltech that I may grab.
Ricktalife
Member
- :
- 2012 Subaru WRX
This is all very disappointing 
I wasn't expecting the FIC to be as good as a standalone, but I really was hoping it would suffice in keeping the ECU at bay. I may consider a standalone in the future with an extension harness so I can hopefully save my factory harness from destruction, but for now I don't see that being possible for me strictly because of the cost. I wonder if anybody has tried the AEM standalone on our car yet? I know they have pretty much ceased updates for the FIC software and have moved on to their AEM Tuner software, which is used for their series 2 standalone. Though I believe they are over $1k so we would probably be best to stick with Haltech at that price.
@jdwk, I really appreciate all the effort you have put into this thing as well as all the information you have provided here. I plan on fooling with it a bit this weekend, so you will probably receive a PM from me that may or may not contain vulgar language.
I wasn't expecting the FIC to be as good as a standalone, but I really was hoping it would suffice in keeping the ECU at bay. I may consider a standalone in the future with an extension harness so I can hopefully save my factory harness from destruction, but for now I don't see that being possible for me strictly because of the cost. I wonder if anybody has tried the AEM standalone on our car yet? I know they have pretty much ceased updates for the FIC software and have moved on to their AEM Tuner software, which is used for their series 2 standalone. Though I believe they are over $1k so we would probably be best to stick with Haltech at that price.
@jdwk, I really appreciate all the effort you have put into this thing as well as all the information you have provided here. I plan on fooling with it a bit this weekend, so you will probably receive a PM from me that may or may not contain vulgar language.
- :
- 03.5 YLW MSP
and a good base map hopefully!!!! lol
justanothermp5
Banned
- :
- Rust Bucket
dam those are good numbers, what size turbo you on?
RunAroundNekid
Member
I don't think I'll be using my F/IC. Just going to pony up and go Haltech.
AEM F/IC 1910 box with all wiring and loop harness
$280 shipped
AEM F/IC 1910 box with all wiring and loop harness
$280 shipped
RunAroundNekid
Member
I don't have smog inspections in Louisiana, only visual. Our state inspections are very, very 'lax.
Ricktalife
Member
- :
- 2012 Subaru WRX
Be sure to post the maps and such
Man!! I hate you!!
