Apex AFC Neo: Confirmed Programming Bug - Karman Function Doesn't Work

[erikgross]

As of 10/24/2008, v1.104 of the AFC Neo firmware is available. Initial testing shows the problem seems to be fixed and that the Neo operates as advertised on our cars. If your "Program Version" (located on "etc." menu) is less than v1.104, contact Apex Integration (A'PEXi U.S.A. - Home Page) to get your RMA number.




Details and data here:
Airflow Signal Output Problems with the AFC Neo

Executive Summary:
After analyzing the data I gathered from my AFC Neo and testing another Neo on a testbench, Apex has confirmed this week that there is a problem with the Karman (frequency-based) airflow correction feature on current-generation (firmware revision v1.103 or less) AFC Neo products. As shown in my logs, the AFC’s output is incorrect and erratic under certain conditions, most notably when the input airflow signal rises above 1000Hz. The problem does not seem to be limited to anything specific to the 3000GT/Stealth platform, and likely applies to any application using the Karman feature.

As you can see from my logs, the output airflow is wildly inaccurate at times, and I do not recommend that anyone use the Karman feature of the AFC Neo until Apex releases a fix. For me, one temporary solution seems to be to keep the airflow signal under 1000Hz, as the car seems to be have normally under those conditions. The solution I’m currently using (so that I can run 450cc injectors safely) is to decrease my base fuel pressure from 43psi to 33psi; that lowers the injector output enough that the OEM ECU can compensate for the extra fuel. Then, I can ***EDIT 9/22/08: remove gray text... either turn off the correction on the AFC Neo or I can*** return the ECU wiring back to stock. This allows me to drive the car without having to swap my OEM fuel injectors back into the car.

Apex is working on a fix now, and I’m hoping to be able to test a revised version within the next week or two(i.e. before the end of May). Hopefully, the fix will be a simple reflash of the firmware that can be applied to all existing AFC Neos. Much to their credit Apex has (save an initial delay in confirming the problem) been very responsive and seems to be trying to do the right thing. I will post an update to the web page above (and this thread) when I’ve received the revised version. If you have an AFC Neo, check back on this thread or my website for updates -- as of now, I think I should have something to report by the end of May.

Update 9/22/08:

I've found that the AFC Neo does indeed corrupt the airflow output even when the correction is turned off (map grayed out). This means the only safe way to run your car with the Neo is... well, you can't. Take it out completely and return your wiring to stock until the updated version of the Neo is released.

The attached chart shows Neo behavior during a WOT run with airflow correction turned off. The orange line is the input airflow signal (from the MAS). The med blue line is the actual Neo airflow output (going to the ECU). They should be the same. They're not. Bad. The pink line is the AFR, and the horizontal bars represent 11.5:1 and 10.0:1. Note that when the blue airflow signal (from Neo) takes a dive, there's a lean spike - that actually generated some mild knock. Not cool.

[Import Power]

FUCKING FINALLY!
We called and talked to their techs multiple times and were just shrugged off. We were running in circles trying to tune them to no avail.
We knew we weren't idiots, but they made us out to be.

Finally, proof it's broke!

Great work! Thanks!

[J-Groove]

Wow, the long rumored problem came true.

I had heard that something was screwy, which is why I have a SAFCII in my car and not a Neo.

Don't a lot of cars use Karmen? You would think this would have been addressed a while ago, maybe before production.

-John

[SkortchGT]

I'm glad I never went the the Neo. SAFC I FTW.

[GTO NEMESIS]

Subscribed. (As I have fitted one to a car last week and I need to tune next week, assuming I finish building the Evo which is taking up my garage at the moment ).

Nice to know in advance that I could have issues!

Thanks
Mark

[ace_mechanic71]

I have one, are they going to replace it?

[ZephTheChef]

Originally Posted by ace_mechanic71

I have one, are they going to replace it?

I doubt that, you'll probably have to send it somewhere to have it re-flashed.

[BET-RHD]

No joke its about time! I played with it on a customers car for 4 hours and wasn't getting good results ended up not charging him.. Damn Neo..

[slage]

I opted for a SAFCII instead of the Neo for these rumored problems. (even though the II was out of production when I got it) Glad to see that they are not just rumors anymore and the problem is going to be fixed

[erikgross]

Originally Posted by Import Power

We called and talked to their techs multiple times and were just shrugged off. We were running in circles trying to tune them to no avail. We knew we weren't idiots, but they made us out to be.

While I was never treated like an idiot, it did take them a while to acknowledge a problem. I *completely* understand your frustration about running in circles. I couldn't tune for any leaner than 10.5-11.0 at WOT without random, sporadic knock, and that's richer than I'd like. The car also ran like crap at WOT over 4000RPM. Interesting to hear the exhaust note change and the car accelerate harder when the AFC freaked out and made the mixture go lean. Interesting until the palm started beeping about knock, anyway

I can't believe this product has been out for over 2 years, and they're just now fixing a showstopper bug in the Karman feature. But at least they seem to be aggressively pursuing a fix at this point. I had just rerouted all my dash wires and had everything nicely installed. Wasn't looking forward to ripping the AFC wiring out