tboboy

iTrader: (17)

Hey guys. Ive searched regarding this issue but wasnt able to find any solution. After install of FIC Bluemax 1450, my car lightly (hesitates), jerks every minute or so during 2500-3000 rpm cruise. AFR swings 13-16 during. On the log it looks like STFT jumping from +/- 5%(usual) to +/- 20 or more.

LTFT low: 0
LTFT Mid: +1
STFT's ~ +/- 5%

Here is my injector scaling/latency, Maf scaling:



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Here is a shot of a log when it happens:


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Right column is air volume, does that have anything to do with it?

tboboy

iTrader: (17)

Any advice guys?

tboboy

iTrader: (17)

bump

tboboy

iTrader: (17)

Noone?

igo4bmx

iTrader: (17)

leaking at the seals?

Boosted Tuning

iTrader: (12)

Need more info .. and pic of fuel map and open loop settings

Also the log you posted has no column names so it hard for me and other to check it.

tboboy

iTrader: (17)

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Updated log columns

Here is AFR map:


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Open loop load and throttle scaling is stock
Also, can that be sympthoms of leaking injector seals?

tboboy

iTrader: (17)

bump

Fast_Freddie

iTrader: (50)

It is a low injector pulse width jitter associated with the FIC1450s and it is more pronounced on certain cars. Does this happen when your foot is barely on the pedal? This was happening to me when i had them, other than that they are great injectors...

tboboy

iTrader: (17)

Yes, hapenes when the foot is very lightly on the pedal. So is that normal? Should I worry about it?
Also I filled up with E85 and changed scaling to 1008 and it actually feels smoother now.

Fast_Freddie

iTrader: (50)

For me it was normal for the injectors, i just dealt with it as they worked fine the rest of the time. And yes once you switch to E85, the symptoms basically disappear.

Jack_of_Trades

iTrader: (17)

A lot of large injector guys are going to an aftermarket Fuel Pressure Regulator setup so they can lower the static fuel pressure from 43psi to 35-40psi so they can induce a longer IPW at idle and it seems to work very well. You don't want to lower pressure too low or it will begin to affect the spray pattern of some injectors depending on the nozzle design.

I tuned a set of 2150's for the first time recently and thankfully the car already had an AFPR on it otherwise the pump gas tune would have suffered a bit of drivability IMO. Dropping the static pressure made a world of a difference at idle and light cruising.

Liqquid

Been having some drivability issues since going back to pump for the winter, this is something I've been wondering about since then... fuel pressure is reading higher than it should and I haven't been able to determine why, thinking about adding an adjustable regulator and mechanical gauge, my afr's are swinging all over and I also get that random "stumble" at cruise with light throttle