Hey guys, I have a pretty good grasp on basic tuning on the AEM, but am still fairly new.
After doing a few WOT pulls I have gotten my tune pretty solid for a street tune. (11.3-11.6 AFR's till redline with less than .5 volts of knock) but I am having trouble getting a couple things tuned.
First off is the idle. Car will idle fine at 14.5-15.0 (at 900 RPM) (Idle learn value around -2%) when I come to a stop, but after about 10 seconds of sitting at idle, the car will idle down to about 750 RPM's and the AFR will drop to the 10's and about want to stall, then without hitting the throttle it will jump up to around 1100 RPMS. It will continue to do this bouncing between 10 AFRs and 14's. Maybe someone can look at my tune and see if I have something jacked up.
Next is Decel... Lets say I am in 3rd gear decelerating (0% throttle) at around 3,000 RPM's... the AFR will be at 18.0 + (decel AFR's .. which are ok) then all of a sudden drop to the 9-10 AFR and start bucking back and forth while jumping between 10 AFR's and 18's. Im sure there is something I have screwed up in my tune and hope someone can find it!
Last thing is cruising.... pretty much what I have described earlier in the other scenario's. I am cruising along at like 2300 RPMs and the A/F's will jump from 14.5 to 11 then back to 14.5 causing the car to jerk.
Here is one thing that MIGHT be causing some issues. Before I bought my AEM, I was using a SAFC to tune with. After installing the AEM, I decided to leave the SAFC on (but 0'd out) just till I had the chance to take it off and sell it. Well, yesterday I decided I would do just that (sell the SAFC). I disconnected the quick disconnect (from SAFC box and actual wires running to ECU) and wanted to make sure my car would still start just in case, and to my disbelieve, the car would not start at all. Could the SAFC be causing some type of signal issues with the AEM? I do know recently my SAFC readings have been spazzing out. (Throttle % on SAFC would jump in between from like 3% to 50% spaztastically while holding a constant throttle and my KpA would read like -101 KpA and would not change till I got to like 1 psi of boost on my actual gauge.
Anyways, I am going to stop typing considering this is a very long ass Thread, but I just wanted to explain in good detail everything that is happening.
Thank you for your help!!!
you should post a couple logs, with the aproprite screen pulled up for each problem, its realy hard to diagnose someone elses tune as the EMS has a ton of different ways and stratiges to tune, as for the idle i would double check all your values then turn each one on and off to find out where the glitch is (or get real firmiliar with the logs) and I would do the same with decel
OK so what i would suggest just to start out is
set up your wide band, you havent asigned one and the gain is at 1.15 (way to high for anything) search for how to set the gain for your WB and if you have the 1510u just leave it alone
next I would suggest taking advantage of the WB you have it off under 2000 rpm's and only into 9.?? load (use it all over the place)
then i would smooth your map there are some huge differances that will make the car unhappy, the map should look smooth it can have bumps for VE changes but should be smooth cell to cell transition, should be linear from load point to load point at and given RPM (i understand you havent tuned every cell yet)
i think you have a good start, just looks like a couple minor things to fix before you move on
Hmmm... sounds good. I will try messing with a couple of those things.
You know, for paying almost $2,000 for the AEM, you would think that AEM would offer some type of "basics" , "intermediate" , and "advanced" training video's to go along with the software. Even if you have to pay like $20 per video. I sure as hell would buy it!
I personally learn really quick by watching someone do something, then me doing it myself.
Anyways, I appreciate the advice. I will try to fix a few things that you suggested and smooth out the tune a little. Its not too bad though for a street tune and not being too experienced with the software.
Oh, and like I said about that damn SAFC... I tried to pull it off yesterday and after disconnecting the plug harness on the SAFC, my car wouldn't start (almost like it wasnt getting any fuel at all) I plugged the harness back in and it fired up.
Quote: Originally Posted by nutz
OK so what i would suggest just to start out is
set up your wide band, you havent asigned one and the gain is at 1.15 (way to high for anything) search for how to set the gain for your WB and if you have the 1510u just leave it alone
I do have the 1510u (wideband version) so your saying just leave those setting alone?
Oh, another thing. You are saying that I am not taking advantage of my WB. It shows that its off over 9.97psi and off under 2,000 RPMS? Thats kinda odd. Does that mean that the WB doesn't work under those conditions? Because it works now over 10psi and at idle without a problem?
Also, what exactly is the O2 Feedback target map used for? How does it work with the actual Fuel Map?
^if you just disconnect the harness from the safc, you will have no map signal.
to stop the bucking on decel, go to dfco, and raise the load threshold. you are probably hovering right around the threshold, causing the injectors to come back on during decel.
Oh, another thing. You are saying that I am not taking advantage of my WB. It shows that its off over 9.97psi and off under 2,000 RPMS? Thats kinda odd. Does that mean that the WB doesn't work under those conditions? Because it works now over 10psi and at idle without a problem?
the wideband will always work, but you have o2 feedback turned off in the areas mentioned.
Quote: Originally Posted by Dasstrum
Also, what exactly is the O2 Feedback target map used for? How does it work with the actual Fuel Map?
it is used to set the target afr for a given point. so once your fuel table is close, you can turn on o2 feedback and the computer can add or subtract a defined amount of fuel to obtain the target afr. sort of like a fuel trim that you set up(i know the aem has fuel trims as well). you can also use o2 feedback to help set up your fuel table. just log o2 feedback target error and add or remove that much fuel from those cells.
to stop the bucking on decel, go to dfco, and raise the load threshold. you are probably hovering right around the threshold, causing the injectors to come back on during decel.
im assuming by dfco you mean "Fuel off below Load" parameter in Options-Decel Fuel. right now its set at -10.67 ... you suggest bumping that up to like -9.96?
Alll of us AEM EMS user need to all meet and have a EMS tinker day....
__________________
The Cobalt firmly grabs you and whisks you along your way instantly.
It does so with authority and poise, but while slipping relatively unnoticed through traffic,
never being violent, or dare I say it, frightening. When you ask the SRT-4 to take you somewhere fast,
it punches you in the face, throws you over its shoulder, and runs, screaming,
so quickly that its tires can barely keep up
im assuming by dfco you mean "Fuel off below Load" parameter in Options-Decel Fuel. right now its set at -10.67 ... you suggest bumping that up to like -9.96?
yes, that is it. to make it easy, just log it and set it a little lower than the lowest value you see when decelerating.
You SERIOUSLY need to smooth out that fuel map! ASAP! The timing map isn't quite as ugly as the fuel map, but it too needs some attention.
Your bucking issues at decel is not only related to the DFCO settings, but also your fuel map. The problem is that some of your low load cells are higher (numerically, meaning raw/DC/PW value is greater) than some of your mid load cells. As Nutz said, you need a smooth, linear transition from one cell to the next.
The reason your idle is going crazy is due to that fuel map. With variation in vacuum signal, the ECU is reading the tune you have in there, and with all the peaks and valleys you have, it's jumping from one set of cells to another. The problem is, you have one set of cells tuned to run 14.7'ish:1, while the others are tuned to run in the 10'ish:1 range.
If you don't understand what I'm getting at, I will post pictures of what I mean later on. I have a busy day ahead of me, and I don't have the time to type it all out, right now.
remember the engine dosnt like huge variations from cell to cell and that will and can cause bucking (lean cuts and rich bogs) the o2 fb can only help minor variation
remember the engine dosnt like huge variations from cell to cell and that will and can cause bucking (lean cuts and rich bogs) the o2 fb can only help minor variation
Did you get the SAFC out yet and the car still run?
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.
Car has idle, cruising, and decel "hickups"
I plugged the harness back in and it fired up.
Linear Mode
