Rich Idle - Please Help!

[white01ss]

Also...how did you come up with the B3701 table and the others?

For B3701 I used this speadsheet I found on the Internet (maybe here I can't recall) that uses an equation to extrapolate the table from a given set of base values. Entering the voltage offset values that Ford gave me it give the entire table. I also tweaked some of the excel formulas in the upper voltage ranges (15+) because they were dropping off too fast.

[white01ss]

I wonder if anyone can answer this...

B4001 Injector Flow Rate says:

"If the fuel rail pressure is NOT referenced to manifold pressure, then decreasing the manifold pressure has the same effect as increasing the fuel rail pressure. The fuel flow rate of the injectors will increase at higher manifold vacuums (i.e. lower manifold pressure)."

Now, shouldn't the injectors flow MORE at 0 kPa (perfect vacuum) and LESS at 80 kPa? The stock tables seem backwards.

Injector Flow Rate from 2001 Z06

kPA (Grams/Second)
0 3.671875
...
80 4.023438

Assuming that the fuel pressure stays constant, flow rate should decrease as the manifold pressure increases (especially from FI). An extreme example, if the fuel rail pressure is 58 psi and boost is 58 psi, wouldn't the IFR be 0 or at least close to zero?

Back to the Idle Issue.....

I know this is ugly, but I've been experimenting with an IFR table bumped up under 35 kPa to lean out my idle/cruise.

It actually help quite a bit in getting the trims inline. Also, when I turned off the MAF the >30 kPa trims came down to negative for the first time since putting on the blower/injectors. Apparently my stock MAF was out 25-50% in the upper freq ranges wreaking havoc on my trims.

Injector Flow Rate (Grams/Second)
kPa Value
0 6.984375
5 7.000000
10 7.015625
15 7.031250
20 7.046875
25 7.062500
30 7.078125
35 6.773438
40 6.812500
45 6.851563
50 6.882813
55 6.921875
60 6.960938
65 7.000000
70 7.031250
75 7.070313
80 7.109375

[joecar]

The kPa scale in B4001 is not MAP, but it is MANVAC.

MANVAC = BARO - MAP

That's why it looks "backwards", but it's not.

Perfect vacuum is MAP = 0 kPa (like you said), giving MANVAC = BARO - MAP = 100 - 0 = 100 kPa.
Zero vacuum is MAP = 100kPa, giving MANVAC = BARO - MAP = 100 - 100 = 0 kPa.

And that's also why the MANVAC scale only ranges upto 80kPa...
because at MAP 20 kPa and below, the injectors won't be required to spray much fuel if any.

[white01ss]

Thanks Joe! I just read your thread about IFR calculations. Very nice. That makes much more sense now.

http://forum.efilive.com/showthread.php?t=4821

So, for the Z06 example:

kPa (Grams/Second)
0 3.671875
...
80 4.023438

WOT would be at 0 kPa, and idle/cruise would be in the 70-80 range?

[hquick]

Dan...have you seen these values?

[joecar]

So, for the Z06 example:

kPa (Grams/Second)
0 3.671875
...
80 4.023438

WOT would be at 0 kPa, and idle/cruise would be in the 70-80 range?

Dan,

[I hope I got your name right...]

Yes that is correct.

Cheers,
Joe

[hquick]

Current tune and log...for your reference Dan.
OLSD, 5.7L Whippled with the 42's.

[white01ss]

Dan...have you seen these values?

No I haven't seen those before. They seem pretty close to the one's I posted in the 10-12 V range, then they start to deviate quite a bit. I wouldn't trust it too much without specific part numbers because they may have changed them over the years.

I know my car ran like poop on the stock table and I couldn't believe the difference changing this table made in the drive ability of the car. IMHO, no injector change should be made without getting the offset table, measured flow rate, and min pulse width programmed correctly. But what do I know, I just started in Jan 08!

[joecar]

You're doing fine, don't let post counts fool you...

[white01ss]

Yes that is correct.

Cheers,
Joe

Thanks!

So I've been dickin' around with the wrong part of the tables! (IFR, IPWVA) I'm lucky I haven't blown up my freakin' motor. Good thing I've only been doing small changes.