Fuel cut isues AND Logger Inoperable

[16g Spoolin TSi]

After much messing around with my AFC trying different settings and many recommended ones i am still hitting fuel cut, currently my lo thr is -15% 1k-7k and my highs are 0% and my thr settings are 50%-80%.... fuel cut usually comes around 35% throttle... any ideas advice on what i'm doing wrong.
The logger also won't connect to my car, i know my obd2 port works because ive had scanners on and off my car, i was told the byte timing could be not set properly but when i set it to 11 i still get the X on my datalogger...
This tuning is so fustrating
~Johnny

 

[turbolarry]

You might want to change your throttle points to 30% for low and 80% for high. Keep the settings very conservitive, -8% across for the lows and -10% for the highs, till your logger is fixed.
Hope it helps.

 

[kpt4321]

I would set the throttle points even lower, like 20% and 75%.

Until your logger is working, use -15% on the lo throttle map and -10% on the high throttle map.

 

[16g Spoolin TSi]

Thanks alot guys... however tonight when i was out driving i really concentrated on when fuel cut hit, its pretty consistent usually 3500rpm at 10psi, i got to thinking could this posibly be a bad sensor? my CEL is on i checked the codes the other day i will post them later bc i don't have them on me right now... but i have all the supporting mods for my setup and having this much trouble with fuel cut is not what i expected esspecially after installing bigger injectors...
And about the throttle points can anyone explain why i would want them so low, i was reading the other night and a few tuners had said they had better luck 50-80, im still new to this tuning stuff and i guess im just confused
Johnny

 

[kpt4321]

You should go to www.apexi-usa.com and read the SAFC documentation to better understand how it works.

However, the basic idea is below your lo throttle point, the SAFC uses the low throttle map only. In between the lo and hi throttle settings, the SAFC will interpolate between the lo and hi throttle maps. Above the hi throttle map, it uses your hi throttle settings only.

You basically want the throttle positions to emulate manifold pressure as well as possible. In most cases, you will see vast driveability improvements by switching from a TPS to a MAP reference, but that's a different discussion.

I always found that bove about 20% throttle, especially with the smaller turbo size you are running, you were going to start building boost. Above 50 or 60% throttle, you're almost always at full boost if you're above the bost threshhold.

Did you change the settings to what I suggested? Running 0% up top means you're running really rich, and you're also giving the ECU the full airflow signal. Changing the full throttle map to -10% should help eliminate fuel cut.

Moving the lo throttle point down might help driveability too.

 

[CanadianTSi]

Running 0% up top means you're running really rich, and you're also giving the ECU the full airflow signal. Changing the full throttle map to -10% should help eliminate fuel cut.

Moving the lo throttle point down might help driveability too.

Listen to the man, he knows his Shit

 

[16g Spoolin TSi]

Kyle, I did everything you told me, same thing same cut at the same point... However as from a driveability stand point the car does feel smoother upon acceleration, a better difference over the previous settings we'll say theres still room for improvement, it feels strong until i hit that 10-11psi point then it cuts... i didn't mention this i changed Boost controllers to a profec spec 2 when i installed it i disconnected both lines from the stock BCS however left the harness connected could any of that have this negative affect.
Again I've said it before and ill reiterate it i really appreciate your assistance
Thanks bro
Johnny

 

[drillo99]

hey I don't think your hitting fuel cut, you say your haveing this problem even at part throttle right? fuel cut occurs from the amount of air flow there is preasent, you would not be hitting it at 10 psi unless you had a big boost leak. I had fuel cut problems for a while and have solved them since and I've allso had the problem I belive you have which is a miss fire dew to the overly rich condition you are at with 550's and the afc set at 0 for the high throttle, try to cut back the fuel to -15 across the high throtlle and see if things improve, all cars are different as the air temp and humidity dictate a lot in terms of air fuel ratios but -15 or even -18 are pretty safe starting points

 

[kpt4321]

Johnny, have you ever been able to pressure test the car? I agree that it does sound like a boost leak issue.

It takes a LOT of fuel to be so rich you misfire, but a big boost leak could do it. On the other hand, a big boost leak, could also cause fuel cut.

 

[16g Spoolin TSi]

Yea actually early next week i have some time off from work and i'm going to see a friend of mine his shop has a vaccum tester that injects smoke into the vaccum lines... can you believe big corporate pep boys doesn't have a machine like that but a smaller time shop does ... but anyways thats my plan... so i won't know until possibly monday of next week, but i thought it was boost leak at first but i don't hear one usually in the past they have all been pretty noticeable but i'll tell you what i find after the smoke test... and i think i'm also going to disconnect that BCS harness as well just bc to me it seems with all the vac lines disconnected the ECU thinks thinks this thing should still be regulating something, correct me if i'm wrong but that seems somewhat accurate.
Thanks again
~Johnny

 

[kpt4321]

Leave the BCS plugged in, otherwise I believe you may get a CE light. The ECU doesn't have any routines that check if the BSC is working correctly.

In most cases, I can't hear my boost leaks, unless they are huge.

 

[16g Spoolin TSi]

The CEL is on one of the codes was something about pressure damn ill have to run out to my car and post it later bc i scanned it the other night using one of those snap on modius bc my logger isn't working so i wrote down LTFT and STFT o2 volts and whatever else i thought was important ill post that info later once i find it...

 

[16g Spoolin TSi]

ok those engine codes, if relevant: Fuel Trim Malf. B1, Manifold Diff. Press. sensor, Insuf. temp for closed loop. LTFT observed at the time was 12.5% and STFT was observed at 17.2%... at idle the timing bounced between 6.5% advanced and 9% advanced... i haven't made a boost leak tester nor have i had time to get to a smoke machine so i dunno if any of the above info is relevant or if by veiwing it a better understanding of whats going on can be had.

 

[drillo99]

hey when did you first have the problem with the "fuel cut", it seemed from your other posts to be after installing the 550s, I also noticed you have those platnium plugs in there, you should get a set of bpr6es ngks (stock rang) plugs, those platnum plugs gave me a miss in no time on my car, that coupled with you being rich will give you a bad miss. I put 680cc injectors in my car and had my s-afc set at -15 and my car bucked and missed at part throttle full throttle whatever, I changed plugs and am now at -36 across the high throtlle and all is well, try setting the afc to -15 on the high throtlle with new plugs and I bet you'll be much improved, you'll probaly be at -20 or more once you start tuning, one more thing is your maf hacked, if so your s-afc settings will need to copensate for that. remember fuel cut is very very unlikely at 10psi with your set up and in what,70 degree whether, and it wont happen at part throttle and only 3500 rpms, and if you tryed the -10 setting mentiond above and still had the "fuel cut" feeling it is definatly not fuel cut as you are telling the ecu that theres 10% or so less air in the intake.

 

[16g Spoolin TSi]

Actually I've always had problems with fuel cut since my MBC stopped working, i installed the 550's and it actually got worst, and when i installed my 550's and profec last week i put in 4 new 6es plugs, at that time i attempted to use RRE's base line afc settings for my car w/ mods but they didn't make it any better... If this isn't Fuel Cut then what is it bc no matter what i adjust to it happens basically at the same point. and the MAF is unhacked, but for some reason i think its going bad and causing this however it doesn't show up in a CEL