Injector data and IFR table

[ferocity02]

I bought some 72# (at 4 bar) injectors from FIC. They sent me the attached spreadsheet with the data already scaled for 4 bar.

My truck ('01 Silverado, 5.3L LS1B 12212156) uses the factory manifold referenced fuel pressure regulator. So at ambient manifold pressure the fuel pressure is ~58psi, and ~52psi at idle. In boost the fuel pressure increases 1:1 just like an aftermarket FPR. The IFR table is flat from the factory as well.

So my question is, for the IFR table B4001 and the Offset table B3701, should I be using the first red row for every row? This is what the spreadsheet said to do. As for the other data, I copied it exactly into my tune.

The reason I ask, is with the new injectors and data, my fuel trims are in the dumps (see attached log), -15% at times on both banks which I think is or near the bottom limit. I'm also getting rick bank 1 and 2 codes, and my fuel economy went down 30-40%. My wideband, when it works, shows 14.2-14.5 when it should be stoich. But the NBO2's are still switching decently.

Do I need to tune my IFR table if I have the data? If not, what the first step to correct this? (this is a MAF tune BTW)

Thanks!

[joecar]

Yes, correct, the red row in the tables for B4001 and B3701.

With engine running, pressure gauge connected to fuel rail, temporarily remove reference hose from FPR and observe rail pressure, it should say 58 psi.

[joecar]

MAF response in log file seems muted and incorrect.

[joecar]

At 167-169°F you're barely warm enough for CL.

[ferocity02]

Yes, correct, the red row in the tables for B4001 and B3701.

With engine running, pressure gauge connected to fuel rail, temporarily remove reference hose from FPR and observe rail pressure, it should say 58 psi.

Yes it reads 58psi with the hose removed.


MAF response in log file seems muted and incorrect.

What do you mean? The MAF has been moved from the stock location to the cold piping. It's at the end of an ~18" straight section with a 90 deg bend right after it. The MAF calibration might be one that I was working with Calc.VET when it was in the stock location. But it hasn't been touched since moving the MAF.


At 167-169°F you're barely warm enough for CL.

I think CL activates at 131F? It has a 160F thermostat.

[joecar]

Do you have more logs showing more RPM range...?

[ferocity02]

Do you have more logs showing more RPM range...?

I'll make one on my way home today.

[ferocity02]

Here's a log from the drive home. Tried to get a little more RPM in there but I'm hesitant to get too crazy with this tune at the moment, especially with my wideband going bonkers.

I don't want to post the tune since I told my tuner I wouldn't.

[ferocity02]

Turns out FIC sent me the wrong data. My injectors are actually 72# at 3 bar not 4 bar. So the PCM thought the injectors were smaller than they actually are, causing the rich condition :ermm:

They sent me new data to try.

[ScarabEpic22]

Turns out FIC sent me the wrong data. My injectors are actually 72# at 3 bar not 4 bar. So the PCM thought the injectors were smaller than they actually are, causing the rich condition :ermm:

They sent me new data to try.

Yea, that'll do it! Means they're more like 80ish lb injectors then!

[joecar]

Post a new log with the new data.

[ferocity02]

Attached a new log. Wideband decided to play nice this time, although its reading slightly less than stoich when the NBO2's are showing stoich. The LTFT's are better but still fairly negative, and get down to -14.8 at times. I was hesitant to get into too much boost because the AFR was now 12-12.4 which I'm not sure if its too lean. Before the correct injector data the AFR was about 10.5 in boost. I didn't get above 5psi in the log.

Another problem I'm having is that when I put the injector data into the tune file and save it, when I reopen the tune the injector data changes. For example, when I put an IFR of 83.14, it will change it to 83.15 lb/hr. And for a small pulse adjust between 0.001 ms and 0.019 ms, it changes them all to 0.015198 ms. The rest of the values are some multiple of this value. Is this normal? These errors are probably in the noise but was just curious.

Also attached the new injector data.

[joecar]

The 0.01 change you saw is "discretization error"... it is due to the bitwise representation of a real number... it is just noise.

[ferocity02]

The 0.01 change you saw is "discretization error"... it is due to the bitwise representation of a real number... it is just noise.

That makes sense. So for the small pulse adjust, should I manually round the values to some multiple of the minimum allowed value of 0.015198ms? When it rounds them for me, it rounds them all up (ceiling rounding). But using traditional rounding some should round down to zero.

And for the IFR table, if I am using the data from FIC for the injectors, is there any further IFR table tuning to be done? Or will the remainder of the tuning be through MAF/VE?

[joecar]

The data from Jon @ FIC should be pasted in as explained in his spreadsheet.

The remainder of the tuning is VE/MAF.