Silver02Z28

iTrader: (2)

I posted this in "Fueling & Injection", but I did not receive any help.

I installed some 39# blue tops yesterday, edited the IFR, and now my LTFTs are at 25 and I'm throwing lean codes.

I used the injector spreadsheet from HPTuners to obtain the values for my IFR. I first assumed that the injectors are rated 39# at 39.15psi, then changed the IFR values for 39# at 3 bar. Both IFR table values gave me high LTFTs.

I added 25 to the main VE table, but the LTFTs settled back to 25. Just for kicks, I took 25 out of the VE and I got the same result.

I see normal LTFTs with the stock injectors and IFR table, but the blue tops throw them out of whack. I'm going to check my rail pressure just to make sure something isn't wrong there.

Is there anything else that I need to address in the fuel control for these injectors (PW etc.)?

Here are the IFR tables I am using.

0-80kPa

39# at 39 psi
46.94 47.25 47.56 47.81 48.12 48.43 48.67 48.98 49.23 49.54 49.79 50.1 50.35 50.66 50.91 51.15 51.46

39# at 43.5 psi
45.02 45.33 45.57 45.88 46.13 46.44 46.69 46.94 47.25 47.5 47.74 48.05 48.3 48.55 48.8 49.05 49.36

More info:

I just checked my fuel pressure and it's 58psi dead nuts.
I sprayed for vacuum leaks and found none.

I also set my IFR to the stock 28# injector slope and the trims went way negative with the 39# injectors installed, as expected.

Anyone have any ideas?

jimmyblue

iTrader: (11)

Look at the trims by LTFT cell and for that matter, fix up the
FTC boundaries so they are sensible (putting all of them in play
and concentrating most of them where you are certain to be
in closed loop). Then the data you get, will not be a big smear.

You have two aspects to deal with - main flow, and offset.
Every different injector has a different time to open/ close
which is an error between electrical and fuel. It's accounted
for, but nobody gives you useful data for anything but GM
OEM applications (via the back door, at that).

If you find the FTCs like 0, 1, 4 are really bent and the ones
that run higher pulse widths are nearly clean, suspect the
offset table needs work. You might be able to back into it
using the trim data as a guide, after of course rechecking
that you have sane IFT table values w/ vacuum and so on.

For FTC RPM boundaries try something like 1200, 2500, 4000
and MAP, maybe 40, 50, 60 (lowest should be above idle or
low-cruise MAP, whichever is more and the highest FTC
boundary, below your PE enable MAP). Ideally you would
want to "waste" only Cell 15 on WOT/PE and the others
should all have some relevance to the driving envelope.
On my car stock, upper 2 boundaries for RPM were above
6500. Useless, half of the cells.

Silver02Z28

iTrader: (2)

Thank you for the advice Jimmy. I'll go ahead and modify the cells with something like you suggested, then take some logs. I'll probably end up posting them for some more help.

My boundaries are like you stated: RPM 2500, 6502, 6503 and MAP 32, 57, 77.
My PE Enable MAP is 15, should that change? That seems low to me.

SSpdDmon

iTrader: (10)

Sounds to me like they may be rated at 4-bar. You say you assumed...you should check and be sure. That would make sense too because I believe the difference between those injectors at 3-bar vs 4-bar is about 20%.

Silver02Z28

iTrader: (2)

They could be. After researching, I found three different values. They are 39.15, 40 and 43.5. I'll bet the trims would be right if I sloped them for 58 psi. But I'm going to try Jimmy's suggestions before I try to fudge the IFRs.

Silver02Z28

iTrader: (2)

Update:
I changed the cell boundaries and did some logging. I found that the low MAP and RPM cell trims needed the most help.

I also did some searching and found that the SVO injectors are not as quick to open as the stock injectors, so I looked into the injector offset vs. voltage vs. kPa vac. I started raising the offsets and the trims came down.

I got to the point where the trims were right about where they were with the stock injectors. This is with the correct IFR data for the SVO blue tops. I feel that I can now go back and tune VE and MAF to get everything dialed-in. There are no bucks or burps, and the idle is smooth.

I'm going to log with the wideband today, and see where I'm at.

Thank you for the help Jimmy.

jimmyblue

iTrader: (11)

Post your final offset table when you're done, as a public
service. Good data is scarce.

rubbersidedown

are you talking about the 39 lb '03-'04 injectors (pencil-like and skinny, look very similar to LS style injectors, they are all blue) or are you talking about the old blue topped with black on the bottom bosch style (fat in comparison to stock) If they are the "blue tops" they are rated at 24 lbs @ 39.5 psi... They injectors that are skinny and all blue are 39 lbers...

Silver02Z28

iTrader: (2)

I'm talking about the 03-04 Cobra injectors. Did I miss-name them blue tops? Crap! Sorry

slow

iTrader: (7)

03 cobra injectors flow between 40.07949829 and 50.00152588 #/hour based on the factory 2003-4 cobra tune file. Ford uses a 2 slope method for fuel injectors. The normal "high slope" is the 40.x value, and it is at a rated 39.19# of pressure drop.

Hopefully this helps, unfortunately, the data on the factory injectors, does not easily port over to the lsx control system.

Ryan

johnh

iTrader: (1)

I used the blue tops on my GTP for a while...

My IFR values based of 3/bar: 42.31385373 - 50.53483102 (varied by MAP). I know doesn't correlate to the LS1, but they seemed to flow a bit more than the 39# listed....

Silver02Z28

iTrader: (2)

Thank you guys. I solved it by upping the offsets. Trims are back in line now.

SSpdDmon

iTrader: (10)

Yes....please post your table. If you could copy/paste it to a basic Excel file (.xls), that would be awesome.

SSpdDmon

iTrader: (10)

Please....