Lean AFR after injector swap

[vatman02]

I just put in a set of 79# injectors,:rockon: and all i changed was the injector flow rate to match the injectors and the afr is real lean, 14:1, :eek: should be 9.8:1 and it idles real strange kinda like the lope from a big cam.:nixweiss: I tried reducing B4307 with no change, I can correct it with A0008 at 1.25. But i would think i should not have to use this to correct it,:bash: just looking for some thoughts on this. :master: Here are two of the logs, the first log is uncorrected the second is corrected with A0008 at 1.25. the idle increased as well with the correction which tells me there may be a vacume? leak but i didn't find one.:D

[redhardsupra]

injectors can achieve their full potential only when the rest of the fuel system is up to the task. what other supporting fuel mods you got in there?

[vatman02]

I have an APS dual in tank fuel pump, Aeormotive fuel pressure regulator. Thats it though, the fuel rails i got with the kit wont fit the injectors so i can't use the two -6 supply lines either, just using the stock feed line with a Magna fuel filter in place of the stock one. I do how ever, have the fuel pressure kind of low at 45 psi.

[redhardsupra]

is it always low or just on WOT? is your IFR table calculated for the 45psi or the stock 58?

[vatman02]

I have not even taken it out of the garage yet, it has very little gas. I just installed everything over this last weekend. I was just checking to make sure everything is in working order and to adjust the regulator, but from the limited reving it stays dead on 45.83 psi. And yes, i used one of your excel spread sheets to calculate for 45 psi., then input that into the IFR table. I didn't want to set the fuel pressure too high because i could not get the 60#er's i had before the D1 and E-85, to work right. I haven't been able to figure out how to properly tune for large injectors yet, I thought it would easier if the pressure was lower. Also the regulator is not referenced too manifold vaccume, so it should be constant.

[5.7ute]

I have not even taken it out of the garage yet, it has very little gas. I just installed everything over this last weekend. I was just checking to make sure everything is in working order and to adjust the regulator, but from the limited reving it stays dead on 45.83 psi. And yes, i used one of your excel spread sheets to calculate for 45 psi., then input that into the IFR table. I didn't want to set the fuel pressure too high because i could not get the 60#er's i had before the D1 and E-85, to work right. I haven't been able to figure out how to properly tune for large injectors yet, I thought it would easier if the pressure was lower. Also the regulator is not referenced too manifold vaccume, so it should be constant.
Not referenced to manifold pressure is a curve, referenced is a constant.

[vatman02]

Not referenced to manifold pressure is a curve, referenced is a constant.
Doesn't this only apply to the IFR table, not fuel pressure?

[redhardsupra]

IFR table is a result of fuel pressure, so you change one you change the other.

[joecar]

Fuel pressure:
- unreferenced regulator -> fuel pressure stays constant
- MAP-referenced regulator -> fuel pressure varies as MAP varies (MAP "assists" the spring inside the regulator)

IFR:
- unreferenced regulator -> sloped IFR tble
- MAP-referenced regulator-> constant flat IFR table

[vatman02]

Fuel pressure:
- unreferenced regulator -> fuel pressure stays constant
- MAP-referenced regulator -> fuel pressure varies as MAP varies (MAP "assists" the spring inside the regulator)

IFR:
- unreferenced regulator -> sloped IFR tble
- MAP-referenced regulator-> constant flat IFR table

That's what I was thinking. I have a constant fuel pressure and a sloped IFR table. Any thought's on why I'm running so lean. I am going to try reverting the voltage offset table back to stock and see what it does.:nixweiss:

[vatman02]

So i believe i worked it out. :notacrook: At least at part throttle. The voltage correction table did the job pretty well. I just wish I knew this before I sold my 60#er's for half price and bought the 42's I no longer need.:frown: I had people telling me to adjust the small pulse adder, but that always caused a ruff idle. Changeing the voltage table doesn't too cause the idle trouble.:Eyecrazy: I just built a BEN map for that table as well, and it seems to line up with what the wide band is saying. I'm hoping this weekend the wheather clears up and I can dial it in with the map.Thanks for the input.:cheers:

[joecar]

:cheers:

[vatman02]

Well this hasn't worked out quit as easily as I had hoped. I think the intake temps. keep skewing the afr. I have been experimenting with IAT VE multiplier but it's not a complete fix. So in an attept to correct some of the strange fueling I turned on the STFT and when I logged for it I got min.-2.3 max 2.3 I filled alot of cells, all but one were 0.00 the 1 was .03. What am I missing?

So I just tried zeroing out the charge temp. blending table, and the Afr went rich. So I'm confused on a couple of things .
1) By zeroing this table I am using IAT exclusively for fuel adjustments. Correct me if I'm wrong. But as the IAT went up the fuel mixture went richer. Does not hot air need less fuel and cold air need more.
2) This blending table is based off SAE.MAF, I don't have the MAF plugged in. How can this table work if there is no MAF signal.

[vatman02]

could someone point me in the right direction to correct this. The Ben goes from 1.3 to .8 . I need to know what to log to correct this.

[joecar]

What rail pressure did you measure (and calculate IFR for)...?

79# injectors are fairly big, I wonder if the PCM is just shutting them off too quick at idle (since the IFR table now says they flow alot)...?

May need to play with some of the other injector tables (e.g. someone put in negative offsets to get 96# injectors to idle properly).

[vatman02]

Thanks joecar,
I,ll give that a shot. I have fuel pressure set at and messured at 45 psi. What is confusing me is that the pulse width and flow rate didn't change nor did manvac rpm fp map ect iat just the afr. I went through red hat supra's marcin transformation that logs new ifr and old ifr to calculate if the if ifr table is correct. It was 4% off, so I corrected that.