VW Vortex - Volkswagen Forum banner

Installed BFI Stage 2 Chip, ran great for 4 days, now idle problems & rev hang

97K views 398 replies 27 participants last post by  dailygolfer 
#1 ·
I had a GIAC chip installed, and went over to the BFI stage 2. Once running, the car ran fantastic for about 4 days. I was really pleased that the rev-hang issues (revs hanging up between shifts) were gone (when I let off the throttle, the revs dropped quickly back to about 1050rpm idle). Then a problem developed suddenly where the rev-hang returned and when coming back to idle, the engine will float between 1500-2000rpm for a few seconds before returning to idle. The rev-hang is much more noticeable now than when the GIAC was installed. When cruising around 1500rpm, I can feel the motor trying to pull gently towards 2000rpm. Intake system is clean and no check engine light. When I put the GIAC chip back in, it seems to run just like it used to (same amount of rev-hang, returns to idle quickly). Re-install the BFI chip, and the problem is back, even after clearing the ECU via VAGCOM (just to clear whatever learning sequence it does). Thus far BFI doesn't have an explanation. There aren't any vacuum leaks. I took the cover off the idle control motor, cleaned it with contact cleaner, and nothing appeared visually broken in there but it's obviously not serviceable. The only thing I can think of is the throttle body needs to be replaced, but I don't understand why the problem doesn't show itself with the GIAC chip installed. I can only surmise that the BFI chip is actuating the idle control motor in a different manner and the original idle control stepper motor can't keep up?

I posted videos to exemplify the problem.

http://www.youtube.com/watch?v=Y6og6H0SHGA

http://www.youtube.com/watch?v=-AkaxO9lUYM

http://www.youtube.com/watch?v=_x6-QMbg7M8

http://www.youtube.com/watch?v=zFPj1mwtx3w

http://www.youtube.com/watch?v=np7fesgM2H4

What the hell is going on? I'm super frustrated because the car ran the best it ever had for about 4 days.. and now it's all gone to **** again grr.

-Patrick
 
See less See more
#37 ·
Lol ok to make it short....cheap eBay part confuses o2 by sending more air into the chamber thus preventing my CEL ...and gave me 33mpg to h2oi....I've NEVER had good mileage like that..I probably have the code pending but:peace: aleast I'm not clearing my ecu everyday with my scanner....better? :D:peace:
 
#40 · (Edited)
i have a 98 aba with exactly that issue..the rpms hang at 2000 rpms then it jumps up and down a few times before it settles at idle(i'm glad i'm not the only one)i have replaced the following TB ,MAF, FPR, new coil , pcv system, evap purge valve,plugs and wires , coolant temp sensor , all vac lines replaced and tested and all new intake gaskets...then i put the stock chip back in and issue is gone..which leads me to believe its a software issue:(.....but i will say this i was really impressed with the performance of the 268 cam and stage 2 chip and the customer service so far hopefully the issue is resolved and i can enjoy my car again:beer:

p.s also get the P0172 as well

ill be watching this thread closely
 
#42 ·
i have no idea what you said either gtiswapped96...you put a compressor on your intake elbow after the MAF or before? like a BOV for n/a cars? it builds pressure? so wouldn't that make the car run richer? or it tells the MAF its already running more and it then tricks the ECU into running leaner? i'm confused.

BFI contacted a few of us today and they are testing some new modified tunes for the cars to see if they can eliminate the problem...very impressed with their customer service right now.
 
#45 ·
I'm absolutely floored by that product. That thing is a piece of **** and a waste of money.

What you 'installed' is a controlled vacuum leak. :facepalm:

You are probably unaware of this, but that isnt 'tricking' anything from your ECU. Any unmetered air, not measured as load from the MAF, will be compensated for when the ECU cranks up your fueling trim table percentages. Or until you reached your maximum and the CEL throws one of the P017X codes. Motronic ignition is way smarter than you think. Even trying to trick the MAF with diodes would only work on the open loop cycle. The ECU is always trying to keep stioc (14.7) fueling in closed loop, and it wouldnt be till you went into an open loop would you see any difference. I could see this working on a MAP-based system, like a Honda (this is an HKS product after all).

That being said.....

I have no idea why something as stupid as this is keeping your CEL off. I would be curious to see what your short and long term fueling tables look like right now. I would bet that this...device...is only a short term band-aid and once your fuel trims are adjusted to compensate for the vacuum leak, you will get a CEL. I just cannot accept this as a 'fix' for this issue.
 
#46 ·
Like I said in my previous post I'm completely aware that this is a vacuum leak....I also know that what I bought is a knock off hks part..if I woulda found one that had a big German flag stamped on it I woulda gotten that instead...I've tried everything imaginable to get rid of that code including pm'ing u numerous times about this code without any luck(which I'm not blaming u for cause I'm sure u get tons of messages about technical stuff) so I've gone with less traditional methods....now I'm not asking for any1 to "accept" what I did cause at the end of the day its my car and I'm the one that's gotta fix it....it just turns out that now my CEL won't come on everyday after I "installed" this knockoff ebay "controlled vacuum leak"....no sense in pointing fingers and laughing at the dude trying to figure his sh*t out...

With that being said....
I'm not here to knock on no one especially tdoggs cause he does help a lot of people here on vortex...I'm just trying to do my part in fixing a problem that a bunch of us are having:peace::peace:
 
#47 ·
My point was, you didn't fix anything. If you were getting a CEL every day, there is a HUGE issue within your system, either being fueling (MAF/O2) or vacuum related.

What was the code you tripped every day?
How do you know you were running too rich? Do you have a wideband AFR gauge? Or maybe VAGCOM printouts?

Not trying to be a hard-ass, just trying to figure this out.
 
#48 ·
P0172 bank 1 sensor 1 too rich...popped it everyday new maf new o2 sensor and can't find a vacuum leak anywhere other than the obvious one I have now....I would give u some VAG_COM info but to be honest I can't work it 100%. I only mess around with it when I try to adjust my tb....get pretty bad city mileage but great highway...she was giving me 33 mpg on the way to OC which I've never seen before
 
#49 ·
And as far as my a/f gauge goes its divided into three parts lean,stoich,and rich....and most of the time it jumps from lean to rich back and forth like crazy, fluctuates a lot. Used an old school o2 sensor to hook it up(single wire type brand new)....I had an xtra Bung in my system so I figured y not, I really didnt wanna tap in to the factory o2 sensor wire
 
#51 ·
Yeah ill agree with that...its just the wideband was 300 and I was told thats used more for guys running boost which I don't have(yet:D)....there's really nothing else I can check or change to make sense of all of this but then again ive always got crappy mileage even before all my mods but no CEL ...I'm guessing the more aggressive tune just made the problem more visible for the ecu?..these are all "maybes" and "ifs" Ofcourse..going out on a limb if u will
 
#52 ·
Widebands are useful regardless. Its the only accurate way to relay your fueling. You can get an AEM UEGO for under $200 shipped on Ebay. Its right up there in usefulness as your scanner gauge.

The crappy city, but good hwy mpgs tells me that you closed loop is fine, but once you go into open loop, you have massive issues.

Have you checked your fueling system yet? Injectors and fuel filter? Almost sounds like a stuck/clogged injector.
 
#55 ·
you put in ABA injectors right? (just checking)

Im stumped. P0172 is related to these in order

Bad/dirty MAF
Vacuum leak
injector issues

The code trips after you exceed the mazimum percentages adjusted on the short and long term fuel trims. But you replaced everything.

Have you swapped the stock chip back in to see what happens?
 
#59 ·
Thats just the VW 3.6 V6. Its shared through a lot of platforms.

So this thread doesnt get derailed any further, my advice to you would be to remove both the vacuum leak device and the PEM. Run the stock chip and diagnose from there. There is something significantly wrong with your motor. Remove the questionable variables and go from there.
 
#61 · (Edited)
I haven't posted in a liit, but keep giong back and forth through PM's with some of the guys in the thread.

I've also still got the p0172 code ('98 wolfie 5spd) on the car with the chip installed. I also get the same idle issues, I did adjust my idle down from the ~1050-1100 the chip came set with (did that this weekend). I have it set at ~925, and in order to adjust it I had to modify channel 01, but the others did not cause a change in idle speed. (channels 02-05)

Looking at the vagcom screen I can see it's saying roughly -7% lambda numbers, I've already tried 2 sets of injectors, 2 maf's, 2 throttle bodies, new upper intake gasket (valve cover and throttle body too), plugs (different gaps and types also) , wires, cap & rotor, fuel filter, fpr, front o2 sensor (rear sensor is currently absent), coolant sensors, new intake elbow, new pcv & grommit, oil pressure sensors, etc. etc. etc.

I've replaced all the vacuum lines I could find over a period of time, tried 2 different purge valves as well. I'm sure there is more that I've done, but can't think of it all off the top of my head. I've been trying to figure this one out for a very long time now. (I had another thread)

The car is not as strong as it was when I first put the chip in, I think the full power lasted roughly 1 week after putting the chip in at H2Oi 2010. The idle and weird hesitation got on my nerves at one point that I just went back to stock for quite a while. I've had the chip in for months now, and the full power isn't there that once was. The car doesn't run bad or anything like that, it runs like say stock power or about that, but VERY noticeably lower from the first day I put the chip in. Always running 92-93oct as well.

@ Travis,

If you want I can do some logging or supply whatever vagcom data you want if that'll help solve this for us all.


Kei

(I'm also MORE than willing to be a guinea pig for a new flash as well)

EDIT: I forgot to mention that I also get that random stalling at idle too sometimes (it's been a while though), but it will act like it's about to cut out at the strangest times randomly...actually that part happened again today
 
#62 ·
I had the exact same issue with my C2 chip and bbm supercharger setup, I just always figured it was because of the s/c and the position of the throttle body. When I put the throttle body on the intake it would stop doing it. It was exactly how you guys describe it though, random idle hanging/raising between 1-2k rpms when coming to a stop. Never had that problem with early non-c2 chips but they also ran like crap and stalled out constantly, the c2 chip was such a drastic improvement that I never bothered to mention it.

Good luck figuring this out.
 
#63 ·
Weird Update: Just for experimentation purposes, I ran 89 octane today and the car seemed to do actually better for some reason. Power felt like it was there and "almost" no throttle lag. It almost feels like the car has more power with 89 vs 93. Just an experimentation.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top