Please Help! NA-T running rough...
01-05-10, 11:43 PM
#1
Please Help! NA-T running rough...
Here's the breakdown:
Disconnected the IACV in order to make the car not fall through idle upon deceleration and the AEM EMS tune was pretty good but not great
A/C did not work anymore and I wanted everything to be as close to factory as possible (other than the aftermarket parts) so in an attempt to get things working right the IACV was plugged back in with a vacuum line run between the IACV and the throttle bottle
Now the car is running really rough (much worse than either of the previous situations) and the fall thorugh idle stalling upon deceleration is back
Does anyone know how to have the IACV connected and have the car run correctly without falling through idle on deceleration and run well also?
I have a Boostlogic Stage 1 NA-T kit with an AEM EMS if that helps...
Any ideas would be appreciated and please ask any questions that would help you make a decision and I'll answer them to the best of my ability.
Disconnected the IACV in order to make the car not fall through idle upon deceleration and the AEM EMS tune was pretty good but not great
A/C did not work anymore and I wanted everything to be as close to factory as possible (other than the aftermarket parts) so in an attempt to get things working right the IACV was plugged back in with a vacuum line run between the IACV and the throttle bottle
Now the car is running really rough (much worse than either of the previous situations) and the fall thorugh idle stalling upon deceleration is back
Does anyone know how to have the IACV connected and have the car run correctly without falling through idle on deceleration and run well also?
I have a Boostlogic Stage 1 NA-T kit with an AEM EMS if that helps...
Any ideas would be appreciated and please ask any questions that would help you make a decision and I'll answer them to the best of my ability.
01-06-10, 11:40 AM
#3
you shouldn't be disconnecting the iacv. I have the exact same setup and it is a little tricky but first connect i0t back like stock then do the following.
get the car up to full operating temperature ~180 degrees.
turn off idle feedback and wideband feedback if you have it on.
go to the idle section and use the target vs temp table to set the speed you want to idle at, lets say 900 rpm. now adjust the target % vs idle map up and down until the actual rpms read as close to 900 you can get it, without going too much below it (910-940 is better than 870-890 range). now you repeat this for every rpm value all the way up to about 2000 rpms. you will notice it wont be very consitent at idling exact above lets say 1500 rpms but just ballparking it here and above should be alright.
now set you high idle offset is set to 0 rpms and delay to 0 second (this is all off the top of my head so if i get the names wrong let me know) and the speed to something ridiculous like 200mph so you don't get stuck in high idle.
turn back all your feedback stuff on, set the idle feedback high initially like 300ms so it doesn't overcorrect a whole lot. +/-75 deadband zone is conservative. for feeback under rpm value set this as low as possible without getting stuck in high idle on starts, I keep it around 1400rpms but lower the better so it doesnt try to idle while your just cruising through a parking lot. from here fine tune the idle % target map and get it so all your learned values are under -3% (If you did the first part right it should be within this). if it is set your -feedback precentage around that and for positive percent you can keep that high for cold starts and whatnot like 8% or so.
this part is more left for a tuner but the timing offset vs idle error map can be very helpful in your car making it to the desired rpm without swinging madly. I have seen up to +/- 10 degrees in this map but I feel like I don't trust the aem to be pulling or adding that much timing while adjusting so many other things. Consideration for what your base timing map is set to in the ranges where you have idle feedback is important especially because cold start rpm's can creap into areas that are tuned for lean cruise which already have advanced timing.
this is one of the reasons I keep idle feedback under 1400 rpms because my timing map ramps at about 1600.
and for the a/c its just in the settings. with the correct settings i found off supraforums my a/c works like factory. no resistors or anything was needed for me.
get the car up to full operating temperature ~180 degrees.
turn off idle feedback and wideband feedback if you have it on.
go to the idle section and use the target vs temp table to set the speed you want to idle at, lets say 900 rpm. now adjust the target % vs idle map up and down until the actual rpms read as close to 900 you can get it, without going too much below it (910-940 is better than 870-890 range). now you repeat this for every rpm value all the way up to about 2000 rpms. you will notice it wont be very consitent at idling exact above lets say 1500 rpms but just ballparking it here and above should be alright.
now set you high idle offset is set to 0 rpms and delay to 0 second (this is all off the top of my head so if i get the names wrong let me know) and the speed to something ridiculous like 200mph so you don't get stuck in high idle.
turn back all your feedback stuff on, set the idle feedback high initially like 300ms so it doesn't overcorrect a whole lot. +/-75 deadband zone is conservative. for feeback under rpm value set this as low as possible without getting stuck in high idle on starts, I keep it around 1400rpms but lower the better so it doesnt try to idle while your just cruising through a parking lot. from here fine tune the idle % target map and get it so all your learned values are under -3% (If you did the first part right it should be within this). if it is set your -feedback precentage around that and for positive percent you can keep that high for cold starts and whatnot like 8% or so.
this part is more left for a tuner but the timing offset vs idle error map can be very helpful in your car making it to the desired rpm without swinging madly. I have seen up to +/- 10 degrees in this map but I feel like I don't trust the aem to be pulling or adding that much timing while adjusting so many other things. Consideration for what your base timing map is set to in the ranges where you have idle feedback is important especially because cold start rpm's can creap into areas that are tuned for lean cruise which already have advanced timing.
this is one of the reasons I keep idle feedback under 1400 rpms because my timing map ramps at about 1600.
and for the a/c its just in the settings. with the correct settings i found off supraforums my a/c works like factory. no resistors or anything was needed for me.
Last edited by Ali SC3; 01-06-10 at 11:50 AM.
01-06-10, 10:35 PM
#4
Ali SC3: Thanks for the excellent and in depth input. I must say that it was way over my head as I turn to the shop for all tuning needs but I'll pass it on to them in hopes that it will help them out.
CP Ree: I have also thought about trying to find someone else who is more knowledgeable with tuning the AEM, but for now we'll see how it goes with Ali SC3's helpful instructions and hope for the best.
Thanks for the replies and I'll keep everyone posted on the outcomes in case anyone else runs into the same problem. It may be about a week though before the car goes back to the shop. I'm headed to Vegas for a few days! While I'm gone I'll be checking the thread though, in case more input has been added...
CP Ree: I have also thought about trying to find someone else who is more knowledgeable with tuning the AEM, but for now we'll see how it goes with Ali SC3's helpful instructions and hope for the best.
Thanks for the replies and I'll keep everyone posted on the outcomes in case anyone else runs into the same problem. It may be about a week though before the car goes back to the shop. I'm headed to Vegas for a few days! While I'm gone I'll be checking the thread though, in case more input has been added...
01-07-10, 07:11 AM
#5
There isn't a whole lot of knowledge about AEM tuning discussed on CL; so, I started one on SF. It was made into a sticky in the dyno tuning section: http://www.supraforums.com/forum/sho...d.php?t=520811
You should give Kurt's post a good read about tuning idle (post #23) as well as my follow-up (post #73).
-scott
You should give Kurt's post a good read about tuning idle (post #23) as well as my follow-up (post #73).
-scott
01-07-10, 10:20 AM
#6
There isn't a whole lot of knowledge about AEM tuning discussed on CL; so, I started one on SF. It was made into a sticky in the dyno tuning section: http://www.supraforums.com/forum/sho...d.php?t=520811
You should give Kurt's post a good read about tuning idle (post #23) as well as my follow-up (post #73).
-scott
You should give Kurt's post a good read about tuning idle (post #23) as well as my follow-up (post #73).
-scott
not every method will work for everyone, so its best to try different approaches.
remember to make small changes at a time and drive the car around. If you get close enough the Aem will try and smooth it out.
oh and the step by step directions I really hope your shop already knows, I was just writing it so you can take a stab at it if they don't get it right the first time. Even the best tuner can't tune everything cause they only get the car for a short period of time. external conditions like extreme cold weather they can't tune for if its the middle of summer so you may find in winter your car not starting at all or takes a few times to get it to start. A GOOD TUNER should know ballpark what the tune should look like so you only have to make minor adjustments. Idle should be something they can get pretty well though.
Oh and there is no time like the present to open up the AEM software and start learning stuff.
It was over my head too, but until you get that holy grail of a perfect tune on your ems, it is likely you will have to tweak it every once in a while and tuners can get expensive for the small stuff.
Last edited by Ali SC3; 01-07-10 at 10:27 AM.
01-07-10, 07:32 PM
#7
I can't thank you guys enough for your helpful input! And I think I will try to learn the AEM tuning program myself. I'm pretty computer saavy so I'm sure with enough practice and guidance from experienced people such as yourselves I'll be able to figure things out. I think the biggest thing is getting over the initial fear of messing something up, haha! Thanks again and I'll keep the thread up to date on what helps with my situation...
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01-18-10, 04:10 PM
#10
Thanks F4A22, it's always good to look at a problem from multiple angles.
Update: After a little tuning (mainly addding small amounts of fuel during decel) we were able to nearly eliminate the problem of the car stalling out after getting into boost and coming to a stop. I had to try all different things to try to make it stall out on street runs but was only able to do it when getting into boost, leaving it in 5th gear during decel, and then popping it into neutral just before hitting my set idle speed of 1100. Under that condition alone it would still break through idle and stall out sometimes. So there was progress made there.
One possible good find was that we noticed that the map sensor (AEM 3.5 bar) was in the red on the AEM software signifying a malfunction. My tuner recommended buying a new map sensor as he has seen them malfunction before. We are hoping that cleaning up the rest of the tune will be much easier and more accurate with a properly functioning map sensor.
Any thoughts?
And one question also. Would it make any difference if the hose from the throttle body to the IACV wasn't the OEM? The one on mine is a lot thicker it seems. It doesn't leak but the length is probably a little different than OEM along with the width. And it's weird because when you rev the motor you can here it sucking around the time it trys to catch idle. Let me know you all think. Thanks.
Update: After a little tuning (mainly addding small amounts of fuel during decel) we were able to nearly eliminate the problem of the car stalling out after getting into boost and coming to a stop. I had to try all different things to try to make it stall out on street runs but was only able to do it when getting into boost, leaving it in 5th gear during decel, and then popping it into neutral just before hitting my set idle speed of 1100. Under that condition alone it would still break through idle and stall out sometimes. So there was progress made there.
One possible good find was that we noticed that the map sensor (AEM 3.5 bar) was in the red on the AEM software signifying a malfunction. My tuner recommended buying a new map sensor as he has seen them malfunction before. We are hoping that cleaning up the rest of the tune will be much easier and more accurate with a properly functioning map sensor.
Any thoughts?
And one question also. Would it make any difference if the hose from the throttle body to the IACV wasn't the OEM? The one on mine is a lot thicker it seems. It doesn't leak but the length is probably a little different than OEM along with the width. And it's weird because when you rev the motor you can here it sucking around the time it trys to catch idle. Let me know you all think. Thanks.
01-19-10, 01:43 PM
#11
good find, decel fuel is tricky, but you dont want it to kick in too soon, just a bit before where you want your idle at unless you love that exhaust "popping sound" you get during decel.
you have to set the aem to use the 3.5 bar sensor from the very start. it doesnt do this automatically. the defualt map is set to 5 bar and you must manuall change the graph to use the 3.5 bar sensor. simply changing the setting in the wizard i dont think works.
I woudln't even try boosting a car if the map sensor is in the red. setting this setting is word for word in the aem install instructions for the sc300. I advise you to check it yourself. And i mean literally word for word. (its normal for your maf sensor to show red cause you removed it, but the map sensor should always be working).
if your car is completely off and it doesnt read 0.0 psi on your aem software it is wrong.
you may want to change the iacv line back to stock sizing, but the AEM should be able to tune around it. IACV and PCV are 2 things I left entirely stock.
you have to set the aem to use the 3.5 bar sensor from the very start. it doesnt do this automatically. the defualt map is set to 5 bar and you must manuall change the graph to use the 3.5 bar sensor. simply changing the setting in the wizard i dont think works.
I woudln't even try boosting a car if the map sensor is in the red. setting this setting is word for word in the aem install instructions for the sc300. I advise you to check it yourself. And i mean literally word for word. (its normal for your maf sensor to show red cause you removed it, but the map sensor should always be working).
if your car is completely off and it doesnt read 0.0 psi on your aem software it is wrong.
you may want to change the iacv line back to stock sizing, but the AEM should be able to tune around it. IACV and PCV are 2 things I left entirely stock.
01-19-10, 03:29 PM
#12
That's funny that you mention the popping during decel because my tuner said the same thing. He was explaining to me the dangers of adding too much fuel on decel and that he would be sure not to do so.
I'll be sure to double check with him to make sure that the proper steps are taken with setting up the 3.5 bar map sensor replacment according to the AEM install instructions for the SC300.
When you say "if your car is completely off and it doesnt read 0.0 psi on your aem software it is wrong" which parameter are you referring to? Boost? vacuum? And what would be wrong? The map sensor? I just want to clarify. Thanks.
I think I will get a factory hose for the IACV in hopes of simplifying things. Thanks again for all the help. I'm so eager to get my car running well again!
I'll be sure to double check with him to make sure that the proper steps are taken with setting up the 3.5 bar map sensor replacment according to the AEM install instructions for the SC300.
When you say "if your car is completely off and it doesnt read 0.0 psi on your aem software it is wrong" which parameter are you referring to? Boost? vacuum? And what would be wrong? The map sensor? I just want to clarify. Thanks.
I think I will get a factory hose for the IACV in hopes of simplifying things. Thanks again for all the help. I'm so eager to get my car running well again!
Last edited by GoCarSc300; 01-19-10 at 06:26 PM. Reason: typos
01-20-10, 10:43 AM
#14
That's funny that you mention the popping during decel because my tuner said the same thing. He was explaining to me the dangers of adding too much fuel on decel and that he would be sure not to do so.
I'll be sure to double check with him to make sure that the proper steps are taken with setting up the 3.5 bar map sensor replacment according to the AEM install instructions for the SC300.
When you say "if your car is completely off and it doesnt read 0.0 psi on your aem software it is wrong" which parameter are you referring to? Boost? vacuum? And what would be wrong? The map sensor? I just want to clarify. Thanks.
I think I will get a factory hose for the IACV in hopes of simplifying things. Thanks again for all the help. I'm so eager to get my car running well again!
I'll be sure to double check with him to make sure that the proper steps are taken with setting up the 3.5 bar map sensor replacment according to the AEM install instructions for the SC300.
When you say "if your car is completely off and it doesnt read 0.0 psi on your aem software it is wrong" which parameter are you referring to? Boost? vacuum? And what would be wrong? The map sensor? I just want to clarify. Thanks.
I think I will get a factory hose for the IACV in hopes of simplifying things. Thanks again for all the help. I'm so eager to get my car running well again!
so after experimenting with various values I found a good spot for my car was at 1400 rpm for the decel fuel to kick in (I also use 1400 for my idle feedback max). so when it hits 1400 and the fuel kicks in it usually catches itself within a few 100 rpm's and at around 1000-1100 rpms its stabilized itself and slowly creeps down to 900 rpms, perfect everytime. much less popping.
what i was saying with the map sensor is that the boost value should read 0 or the vacuum value when the engine is off. boost and vacuum are the same value in AEM, one is positive and one is negative. it should be 0 with the car off.
01-21-10, 10:58 AM
#15
Thanks for the offer 93twintrbo. I might have to take you up on that! We'll see...
Thanks AliSC3, the specific examples of your decel settings are helpful. I'll pass the info on to my tuner as a reference. I haven't uploaded the aem software yet to check the boost/vacuum readings with the car off but I hope to do that soon. What version do you recommend I download. I read that the newest one is available but not entirely fine tuned. What do you think?
Thanks AliSC3, the specific examples of your decel settings are helpful. I'll pass the info on to my tuner as a reference. I haven't uploaded the aem software yet to check the boost/vacuum readings with the car off but I hope to do that soon. What version do you recommend I download. I read that the newest one is available but not entirely fine tuned. What do you think?