Why cant my fuel system support 10psi?

[SSimple]

Ok, i cant figure out why i keep knocking on this new engine. I've always put in 92 octane fuel. Its a 6-bolt, 91 Talon TSI AWD. small 16g turbo, ross 8.5:1 pistons and lots more that are prolly irelevent to this problem

I've swapped out injectors and my fuel pump, in an effort to shed some light on it.

Stock fuel pump, stock injectors = 30+ counts of knock at only 9psi

Walbro 255, stock injectors = 10-15 countsz of knock at only 9psi

Walbro 255, 550cc injectors = Zero knock at 9psi. Sputters and missfires over 4000rpms
At 11 psi, still sputters, zero knock
15 psi, 40 counts of knock, still sputters

Stock fuel pump, 550cc injectors = 15 counts of knock, no sputtering, feels powerfull (9 psi)

Stock Rewired Fuel Pump, 550cc Injectors = zero counts of knock, power to redline at 9 psi
at 11 psi, power to redline, 10 counts of knock


I'm pretty sure my stock injectors were clogged and not flowing correclty, the 550's helped a bunch. Rewireing the fuel pump helped a ton too. Right now i'm running at 10 psi, only pulling 5 counts of knock or so. Car feels great. But anymore boost than that i get some bad knock. I've heard the stock fuel system can support 16psi of boost. I cant get over 10. Would my higher compression pistons (8.5:1) have any effect on this? Or the small 16g turbo? I'm trying to figure out why i cant run the kinda boost most stock cars can?

 

[Boosted4]

when is the last time you changed your fuel filter ?

 

[SSimple]

when i put the engine in, 1300 miles ago

 

[AWDTSiTalon]

What fuel pressure are you running? What fuel pressure regulator do you have? Whats the condition of the rest of your fuel system?

 

[oldman]

Have you done a boost leak test?

 

[SSimple]

Its the stock fuel pressure regulater. My mechanic checked it and said my fuel pressure was fine. Not sure if he's correct, he also didnt believe me when i told him it was a rising rate FPR stock. Thats something i do want to check still. However with the walbro pump on there, my fuel pressure had to be above stock, and still i was getting knock. I have checked for boost leaks, and havent found anything, although I dont see how this would cause any type of lean condition that would lead to knock. If anything it would make it run richer would it not?

In its current State, i have a Rewired stock fuel pump, New fuel filter (1300 miles) Stock fuel pressure regulator, RC 550cc injectors. 9 psi, no knock. 10 psi is where it starts, and it gets worse the higher i go

 

[Carlover121]

Have you tested your ignition timing; are you running too advanced?

 

[SSimple]

Havent thought of that, will check this weekend. When doing this, is there anyway to see what its at currently? or just put is back at 5?

 

[SSimple]

Base timing was set at about 10 degree's BINGO!
Pulled it back to just shy of 5 degree's trying to go on the safe side

Knock is better, but not gone

9 psi Zero knock untill 6000 rpm's about 15-22 counts to 7000 rpm's

13 psi Zero knock untill around 4500 rps, around 15-22 count to redline

This knock now seems like a lean knock again, O2's are hitting .87 ish during the knock.

Any other idea's? or is it time for a walbro & APFR?

 

[falcone4g63]

With those 550's and no afc you are probly running too rich.

 

[SSimple]

It was worse with the 450's

anyways, I reset the computer to clear out the old fuel maps, and took some fresh logs,


This was 9 PSI
TIMA O2 TPS RPM KNK INJP
18° 0.92V 54.1% 2938 0 12.03ms
17° 0.92V 66.7% 3000 0 13.82ms
16° 0.92V 88.2% 3125 0 14.85ms
16° 0.92V 90.2% 3188 0 14.08ms
16° 0.92V 90.6% 3281 0 14.59ms
17° 0.92V 91.0% 3406 0 14.34ms
16° 0.92V 91.4% 3500 1 14.34ms
16° 0.92V 91.8% 3594 0 14.08ms
19° 0.92V 92.2% 3719 0 14.34ms
18° 0.92V 92.2% 3781 0 14.59ms
18° 0.92V 92.5% 3906 0 14.85ms
19° 0.92V 92.5% 4000 0 14.85ms
18° 0.92V 92.5% 4125 0 15.10ms
19° 0.92V 92.9% 4094 0 15.10ms
19° 0.92V 92.9% 4375 0 15.36ms
18° 0.92V 92.9% 4438 0 15.62ms
18° 0.92V 92.9% 4438 0 16.38ms
18° 0.92V 92.9% 4500 0 16.38ms
18° 0.92V 93.3% 4750 0 16.38ms
18° 0.92V 93.3% 4625 0 16.64ms
18° 0.92V 93.3% 4875 0 16.64ms
19° 0.92V 93.3% 4781 0 16.38ms
19° 0.92V 93.3% 5000 0 16.90ms
20° 0.92V 93.7% 4969 1 16.90ms
18° 0.92V 93.7% 5188 0 16.64ms
19° 0.92V 93.7% 5281 0 16.64ms
20° 0.92V 94.1% 5156 0 16.90ms
21° 0.92V 94.1% 5344 0 16.64ms
21° 0.92V 94.1% 5313 0 16.38ms
21° 0.92V 94.5% 5438 0 16.13ms
23° 0.92V 94.5% 5438 0 16.38ms
22° 0.92V 94.5% 5719 0 16.64ms
24° 0.92V 94.5% 5688 0 16.38ms
23° 0.90V 94.5% 5875 0 16.13ms
26° 0.90V 94.5% 5938 0 16.13ms
26° 0.90V 94.1% 5813 0 15.87ms
27° 0.90V 94.5% 5938 0 15.36ms
25° 0.90V 94.1% 6063 0 15.87ms
26° 0.90V 94.5% 6125 0 15.62ms
25° 0.90V 94.5% 6219 0 15.36ms
27° 0.90V 94.5% 6125 0 15.36ms
28° 0.90V 94.5% 6188 3 15.36ms
26° 0.90V 94.9% 6313 2 15.10ms
25° 0.90V 94.5% 6281 2 15.36ms
24° 0.90V 94.5% 6531 1 15.10ms
27° 0.90V 94.5% 6375 1 14.34ms
24° 0.90V 94.5% 6563 1 14.59ms
22° 0.90V 94.5% 6531 4 14.59ms
23° 0.90V 94.5% 6719 4 14.59ms
21° 0.90V 94.1% 6750 4 14.59ms
22° 0.51V 10.6% 6438 0 2.05ms




Here's one at 13 PSI much worse

TIMA O2 TPS RPM KNK INJP
25° 0.88V 71.8% 3281 0 10.50ms
23° 0.90V 80.4% 3344 0 12.80ms
19° 0.90V 83.5% 3438 0 15.10ms
15° 0.92V 83.9% 3563 0 16.64ms
15° 0.90V 84.3% 3656 0 16.38ms
16° 0.90V 84.3% 3813 0 16.38ms
17° 0.90V 84.3% 3906 0 16.38ms
17° 0.90V 84.3% 4031 1 16.64ms
17° 0.90V 84.3% 4156 0 17.66ms
18° 0.90V 84.7% 4281 0 17.66ms
16° 0.90V 84.7% 4438 3 18.43ms
17° 0.90V 84.7% 4469 3 18.43ms
17° 0.90V 84.7% 4625 2 18.69ms
17° 0.90V 84.3% 4656 9 18.94ms
15° 0.90V 84.7% 4906 9 18.43ms
16° 0.88V 84.7% 5000 9 18.18ms
13° 0.88V 84.7% 4875 16 18.69ms
15° 0.88V 84.7% 5156 15 18.69ms
15° 0.88V 84.7% 5031 15 17.92ms
16° 0.88V 84.7% 5344 14 17.92ms
16° 0.88V 84.7% 5375 14 17.92ms
16° 0.88V 84.7% 5281 14 17.66ms
15° 0.88V 84.7% 5469 16 17.66ms
16° 0.88V 84.7% 5719 16 16.90ms
16° 0.88V 84.7% 5594 16 16.64ms
20° 0.88V 84.7% 5594 15 16.64ms
17° 0.88V 84.7% 5688 15 16.38ms
20° 0.88V 84.7% 5906 29 16.38ms
15° 0.88V 84.7% 5844 28 16.38ms
14° 0.86V 84.7% 6063 35 15.87ms
11° 0.88V 84.7% 5969 42 13.57ms
8° 0.88V 84.7% 6063 42 14.85ms
12° 0.86V 84.7% 6094 42 15.62ms
11° 0.86V 84.7% 6281 41 15.87ms
10° 0.86V 84.7% 6375 41 15.62ms
14° 0.84V 84.7% 6281 41 16.13ms
11° 0.86V 84.7% 6375 40 14.59ms
11° 0.84V 84.7% 6469 40 14.34ms
12° 0.86V 83.5% 6531 39 15.10ms
10° 0.86V 51.8% 6500 39 3.58ms
32° 0.04V 11.4% 5781 14 1.28ms
43° 0.06V 11.4% 5156 0 1.28ms

 

[SSimple]

anyone?

 

[Acezwild88]

sorry i have a question when it knocks do the RPM's slow down? im not shure if thats the best way to explain it but it kinda souds like the same problem im having and i can't figure it out either.

 

[SSimple]

as in a loss of power? i sorta does feel like that, but i'm jsut asuming that is because of the timing retard, and all

edit, i was just looking at those logs, and At several point, in both logs, you will notice my rpms drop? now the rev rate was normal during these pulls, but some reason the ECU is showing a decell, than a sudden accell again, is this normal?