4 bar vs 3.5 bar fpr on stage 3

[V1nny]

So after fixing vacuum check valve, replacing spark plugs (thanks everyone for inputs regarding gaping), and cleaning pistons/rings with "snake oil", my 01 Allroad is running next to perfect, but according to my highly accurate sniff test slightly rich.
When I supplied JFonz with all the details for a flash file (specified 415 cc green giant injectors, 3" downpipes, 83 mm maf housing, 5 bar fpr, which was a carryover from old stage 3- setup), the only comment with the file was to put stock FPR back. So i put 4 bar fpr, (is it stock on 2.7t?), and car always smelled like it runs slightly rich. I ordered a new 3.5bar FPR from Ebay for $23 shipped, and would like to try it next weekend. How much real danger of overheating/burning pistons with this fpr? I played a bit with numbers with this calculator: http://www.witchhunter.com/injectorcalc1.php but not sure I understand completely significance of reducing fuel flow by about 8%. If I were smart enough to get real time fuel mix data I would do so, but I am ignorant with anything in vag-com besides getting basic error codes and resetting them, and do not expect anyone to teach me ho to log data. Another approach would be to contact the tuner, but I do not expect JFonz to respond to his customers after couple of years. Should I even try this 3.5 bar FPR?

[julex]

NO, use 4bar.

VAG-COM, measuring block 001 shows you real time O2 corrections AFTER applying long term fuel trims visible in block 032. Block 032 tells the full story, + numbers mean that system is permanently adding fuel (it runs too lean and needs more fuel to hit stoich) and - are the opposite.

Car should never smell rich but only for a very short period of time after cold engine start up.

[V1nny]

NO, use 4bar.

VAG-COM, measuring block 001 shows you real time O2 corrections AFTER applying long term fuel trims visible in block 032. Block 032 tells the full story, + numbers mean that system is permanently adding fuel (it runs too lean and needs more fuel to hit stoich) and - are the opposite.

Car should never smell rich but only for a very short period of time after cold engine start up.

does this mean I am running slightly rich, as suspected?

[julex]

Kind of. You have REALLY antiquated injectors for which JFonz might not have a good data for and thus the tune is off. But, all tuning is just "good enough" kind of affair... I would strongly suggest changing injectors to ford racing ev14 ones (they're superior to green giants) and Jfonz will be able to give you much better behaving map for them.

I would also suggest logging block 032 while you drive, give it part throttle (about 60-70%) and go to 5-6k rpms. Repeat a few times. You will see that "part throttle" values changing as you hit certain rpms/load threshold as the ECU is interpolating these for these areas. What you care for is the value at highest rpms/load logged as that's what goes into WOT fueling calculations. If you see large corrections there, that's a concern as it will directly point to improper tuning of your hardware. if not, then you just have slight non-linearity caused by intake or injectors, or whatever, that's corrected by ECU though so you always have that 14.7:1 when driving around, you don't run "rich" per say as it is corrected on the fly.

[V1nny]

I will try to get these values without getting killed today. Have to figure out how to drive and log data at the same time.. Thank you!

As for the antiquated, I still trust JHM opinion:
These are the same high quality 42lb "Green Giant" Injectors that we ran on our record setting 11.1 @ 130mph full interior K04 powered S4.
Rated at 42lb per hour with a wide spray pattern designed specifically for multiple valve heads (1.8t and 2.7t have 3 intake valves). We have found that these injectors have better idle and part throttle characteristics than larger injectors or injectors not designed for multi valve heads.

[julex]

I will try to get these values without getting killed today. Have to figure out how to drive and log data at the same time.. Thank you!

As for the antiquated, I still trust JHM opinion:
These are the same high quality 42lb "Green Giant" Injectors that we ran on our record setting 11.1 @ 130mph full interior K04 powered S4.
Rated at 42lb per hour with a wide spray pattern designed specifically for multiple valve heads (1.8t and 2.7t have 3 intake valves). We have found that these injectors have better idle and part throttle characteristics than larger injectors or injectors not designed for multi valve heads.

Ok. Won't argue with you and with description put together in 2008 for a product designed pre year 2000, when there were no other choices for injectors. Technology moved since then a lot.

I am surprised that Jfonz just didn't tell you to get better hardware and agreed to tune it. Tuning is the hardest on unknown hardware, this is why tunres usually require you to get very specific hardware before they agree to tune because inevitably saving few dollars on non-standard stuff ends up in your dissatisfaction and lots of time wasted to figure out proper tuning parameters for clunky stuff.

Anyway, how are your injectors clocked? Where are connectors facing in respect to fuel rail positioning?
Cheers.

[V1nny]

Tried to take picture of injectors, but did not come out too good. I think they pointing right direction.
Scanned car today and got misfires back along with suspension leveling sensor:


Thursday,14,May,2015,02:28:33:46862
VCDS Version: Beta 912.0

Address 34: Level Control Labels: 4Z7-907-553.lbl
Control Module Part Number: 4Z7 907 553 B
Component and/or Version: - 2C1A1 X031
Software Coding: 25500
Work Shop Code: WSC 52496
2 Faults Found:

00776 - Level Control System Sensor; Left Front (G78)
57-00 - Electric Circuit Failure
01771 - Control Module for Headlight Range (J431)
79-00 - Please Check Fault Codes


===================================

Thursday,14,May,2015,02:29:27:46862
VCDS Version: Beta 912.0

Address 01: Engine Labels: 078-907-551-AZA.lbl
Control Module Part Number: 8D0 907 551 M
Component and/or Version: 2.7l V6/5VT G 0002
Software Coding: 06752
Work Shop Code: WSC 03058
4 Faults Found:

16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 - -
16685 - Cylinder 1: Misfire Detected
P0301 - 35-00 - -
16686 - Cylinder 2: Misfire Detected
P0302 - 35-00 - -
16689 - Cylinder 5: Misfire Detected
P0305 - 35-00 - -

Readiness: 0000 0000
-------------

Does any one know if this newer type of sensor is interchangeable:
http://www.ebay.com/itm/New-Audi-VW-...-/300956863096
Hate to pay dealership $180, also hope the new design may be more reliable. Looks like two small allen screws is the only thing that holds actual sensor to the bracket.

[julex]

Tried to take picture of injectors, but did not come out too good. I think they pointing right direction.

It is hard to accomplish proper clocking of these, especially two rear ones, so unless you went through this effort (you'd remember that!), they are most certainly clocked wrong.

[V1nny]

It is hard to accomplish proper clocking of these, especially two rear ones, so unless you went through this effort (you'd remember that!), they are most certainly clocked wrong.

Ok, I almost convinced about injectors replacement, but sending ECU and paying for new tune is out of question at this point. Can anyone help me to calculate if these 550cc
http://www.ecstuning.com/Audi-B5_S4-...ews/ES2574528/ will flow about the same with 3 bar fpr as 440CC green giants with 4 bar fpr?

[julex]

Ok, I almost convinced about injectors replacement, but sending ECU and paying for new tune is out of question at this point. Can anyone help me to calculate if these 550cc
http://www.ecstuning.com/Audi-B5_S4-...ews/ES2574528/ will flow about the same with 3 bar fpr as 440CC green giants with 4 bar fpr?

Formula for flow is: New_Flow = Old_flow * SQRT (New_press / Old_Press)

Thus: 440 * SQRT (4 /3) = 440 * 1.154700538379252 = 508 cc/min

So not even close, more over their dead times are completely different as well (older injectors have usually higher dead time). That will have massive implication at very narrow pulse width, like during idle, where wrong TVUB (dead time) has a large influence in fueling errors since dead time compensation is usually much higher than actual needed open time at 100% of flow.

The injectors you listen flow 550cc at 2.7bar - that's how ford specifies flow on these.

Long story short, you're stuck.

[Racin2redline]

i have similar issues with my eurodyne maestro license tune, even after dyno tuning and a street tune i was still making significant corrections at part throttle
its pretty frustrating because my gas mileage and part throttle drivability suffers. for an experiment i threw in a 3 bar fpr. after a little drive no wot this is block 32


figure since 4 bar is 58psi + 1.5 bar boost pressure, i was at 81psi at the rail. -1 bar im at 66psi at the rail at 1.5bar ?
im wondering how the significant drop in fuel pressure affects the fueling at wot. part throttle is clearly helping but once boost comes into play im sort of blind without a wideband, only have trims to rely on

i know our ecus can make up to 25% corrections safely. will it adjust IDC% to compensate for the drop in rail pressure or am i at risk for running dangerously lean at wot(i think this is unlikely with 630cc injectors) but im no pro tuner here


Sent from my SM-G900P using Tapatalk

[julex]

that's simply bad maf table or bad injector KRKTE/TVUB tables. I had maestro in past, it can be tuned to right trims so long you don't use their recommended injector values (they're horrible). What injectors do you have (don't tell me Deka IV, in that case "/sarcasm on" - good luck! - "/sarcasm off" tuning them).

[Racin2redline]

yes deka, i knew they sucked when i installed them but its what the tuner supplied and maestro called for

ive asked a few times to use ev550s or similar to avoid these issues, but here we are! what do i know, im only the customer

julex do you think the 3 bar is helping or hurting the condition?

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[S4man111]

So after fixing vacuum check valve, replacing spark plugs (thanks everyone for inputs regarding gaping), and cleaning pistons/rings with "snake oil", my 01 Allroad is running next to perfect, but according to my highly accurate sniff test slightly rich.
When I supplied JFonz with all the details for a flash file (specified 415 cc green giant injectors, 3" downpipes, 83 mm maf housing, 5 bar fpr, which was a carryover from old stage 3- setup), the only comment with the file was to put stock FPR back. So i put 4 bar fpr, (is it stock on 2.7t?), and car always smelled like it runs slightly rich. I ordered a new 3.5bar FPR from Ebay for $23 shipped, and would like to try it next weekend. How much real danger of overheating/burning pistons with this fpr? I played a bit with numbers with this calculator: http://www.witchhunter.com/injectorcalc1.php but not sure I understand completely significance of reducing fuel flow by about 8%. If I were smart enough to get real time fuel mix data I would do so, but I am ignorant with anything in vag-com besides getting basic error codes and resetting them, and do not expect anyone to teach me ho to log data. Another approach would be to contact the tuner, but I do not expect JFonz to respond to his customers after couple of years. Should I even try this 3.5 bar FPR?

How did the 3.5 bar fit that you bought off of ebay??

[V1nny]

How did the 3.5 bar fit that you bought off of ebay??

It was a really long time ago, I since moved to 550cc injectors and different tune, but from what I remember back then, 3.5 bar FPR had exact same dimensions and fit as stock, but I ended up following the advice here, and just moved onto a different injectors and tune, so I never installed that 3.5 FPR. I may still have it somewhere in the part bin. As for 440cc "green giant" injectors, I remember selling them on ebay for a good price, looks like they still popular with mustang and volvo or mazda tuners.