Ive been messing around with the idle of my car (i can never get it to be how i want it), and am having an issue with idle AFR's. First off, the RPMs do not fluctuate, it have a very steady idle as far thats concerned (+/- 50 of target). My problem is the AFR's always go wild. I cant get them to stay at a "steady" 14.7. i can get them at a steady ~13, but to me thats way to rich for idle, and im assuming will kill my plugs a lot earlier than id like. But as soon as i adjust the fuel table (my idle stays within one cell, on the fuel map) to get close to 14.7 it will start fluctuating wildly. It will swing from 12-17, and never really settle. This video shows it in action. Any ideas on what to try? i can post my config file aswell, if required.


PS. Dont mind the blaring country music in the background lol

 

First of all, please post your setup so we can know where to start.
Thanks.

 

My AFR is acting similar, but not as wild as yours though... I have heard that if you run UEGO to pin c17, it will help the aem set target for the AFR and maintain your target rpm.. Nice music btw

 

What injectors do you have? What is your latency set at?


How are you adding fuel?

 

They are ID1000s, im not sure what you mean by latency, are you talking about the batt offset? If so, its the values for the ID1000 injectors. Im changing fuel by either adding or removing pulse width in the fuel table for that cell, as stated in the original post.

 

Offset/battery offset/latency/dead time/etc are the same and is to accout for the time it takes the injector to fully open based on the voltage they are seeing. The latency for the ID1000's, given on ID's website is a good starting point, but you may have to adjust (likely shift entire curve) to your car. For the most part, latency plays the biggest role in idle and low load cruise (ms)

You actually didn't state exactly how you were adjusting them. You mentioned adjusting your fuel table and not VE/PW.

Do you have O2 Feedback on? If you do, turn it off and what does it do?

 

They are default values from IDs website. And sorry, PW is the default setting for the fuel table in AEM, i had figured it was implied. 02 feedback is on, however it is not set to work under 1400 RPM. so it does not affect the idle values. however if i change it to affect the idle values, it does the same thing, and if i turn it off completely, it also does not change anything.

 

I got that from your last post. They may need tailored to your car. In this non-perfect world, voltages seen at the inejectors may not exactly match what the ECU is reporting, nor compare to another car, nor are once set of injectors going to be spot on with another set, even ID's.

That is still not what I'm talking about.

Not sure why you wouldn't want it on for idle (normal CL operation), but if there is no change, then it is either your VE table, latency, or a combination of both. Between cells in idle, you shouldn't really have any change in that range.

What size fuel pump do you have and what FPR?

 

I turned it off on idle because of this problem, i figured the feedback was making it jump. Since the idle for my car exists in 1 cell in the table (when at idle, it does not jump between cells at all), i was hoping it would make it a little "steadier" by just always trying to apply one value, instead of trying to use feedback to make it perfect.

I guess i am not sure about the VE/PW tables? Could you please explain that a little more?

Also if i make the idle rich, it will stay with +/0 ~.4 of the value (IE if i set it so it idles at 12.5, will only fluctuate +/- a very small value of 12.5 Its when i try to make it stoich, that it starts swinging wildly.

EDIT: Fuel pump is an AEM 320, FPR is the AEM fpr, set at about 43.5 psi

 

VE/PW is the Volumetric Efficiency table you're modifying.

Fuel table can be refereced as your commanded fuel table. With Speed Density, it's used by the O2 Feedback so it knows what AFR you're actually trying to hit.


What I recommend, provided there are no issues elsewhere... Start increasing offset/latency (across the board in .01 increments) while decreasing your PW to see if that helps steady the idle.