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fuel management/correction issues

Posted: Sun Nov 29, 2009 9:37 am
by andrewd_89
I am having a problem understanding whats going on with my fuel system, I previously had 550cc injectors with 55psi of fuel pressure, and it was reaching 100% duty cycle on 14lbs of boost. So I replaced my stock fuel rail and my 550cc injectors with an AEM fuel rail and 1000cc injectors and still using 55psi of fuel pressure, and at 17lbs it is reaching 100% duty cycle on 1000cc injectors.

Another weird issue is say I am in second gear and slowly get on it it will start to lean out at about 7500 rpm and 15 lbs of boost (shown at 10-11 seconds on the graph) no matter how much more fuel I add. But say I romp on it from 1st to 2nd it won't lean out (shown at 1:00-1:15 on graph). As you can see I have a VSS issue but i don't see it being the problem as since it messed up on the second run when it didn't lean out.

One thing to note is that after replacing my injectors I had to increase my fuel tables SIGNIFICANTLY talking like almost 200% from the 550cc

Posted: Sun Nov 29, 2009 9:40 am
by andrewd_89
heres the calibration

Posted: Tue Dec 01, 2009 3:43 pm
by andrewd_89
bump! anybody? thinking about getting 1600cc injectors but i dont want to have to raise those fuel tables almost 200% too

Posted: Tue Dec 01, 2009 5:33 pm
by fly_n
Are u running a resistor block on top of high impedance injectors or something silly like that?

How long had the motor been started prior to that log?
Those air & water temp figures seem a bit suss as well.

Looks like u got a few issues to sort out there,whats with the dud datalog also?

Posted: Tue Dec 01, 2009 8:12 pm
by andrewd_89
actually i might just go check that haha, i bought precision 1000cc low impedance injectors so i installed a resistor box before i put the injectors in, and the package says low impedance but you never know. But that dud i think was actually from accidently hitting the datalog box....anyway what do you mean by sus? those air and water temps seem pretty legit to me but i dont know, the IAT is a brand new AEM sensor.

Posted: Tue Dec 01, 2009 8:47 pm
by fly_n
I dont know where u live,might be somewhere really cold,but your motor seems to not be up to proper operating temps(again,dont know how long u had been running the car for),at least 10degC to low.

Your intake air temps seem really low as well,less than 15degC.
Unless your injesting like below freezing air into the motor at the time or have some super massive intercooler or water injection or something that seems a little low to me,especially on something thats breathing thru a turbo.

I never see below about 25-30degC intake temps on my NA on the coldest day,but our coldest day is like 12degC,so i could be mistaken.....

Is the AEM IAT calibrated to work with a honda ECU?

Posted: Wed Dec 02, 2009 9:37 pm
by andrewd_89
well i just ran another datalog and my iat was mid 80's then got to low 90's. But I think I might have found the problem I did a lot of things tho so not sure what fixed it, but I am thinking it might have been my ignition tables, or my FPR. I put the fuel pressure at 60 and installed a vacuum line that runs from the Intake Mani to the FPR. Took her out on a run and ran very rich which I was actually so happy to see haha.

Posted: Mon Dec 07, 2009 11:45 am
by Spunkster
You need to check your fuel pressure and see what is doing as the RPM increases and boost goes up.