Idle surge!!! & Idle fp w/ 550cc's?

[clipsit]

Hey guys...I possibly have a problem with my idle fp. I talked to the place that tuned my car. They said they left IFP at like 40+ psi!!! I have RC 550 low impedance injectors and I believe I read somewhere on the forum where my IFP should be somewhere between 12-18 psi, and that was w/ 450's? Correct me if I am wrong, but I was told that IFP should not go below about 20 psi? If anyone could help that would be much appreciated? I changed my IAC valve b/c I had a CEL code that said the system was bad. I have to put one screw back on later today, so I will let everyone know if that does the trick, b/c it is surging from 1000-2000 consistently, still. If this does the trick then good, but if not, could someone still please educated me on what my IFP should be w/ 550's? Thanks.

 

[baxsom]

holy crap 550s

with that huge of injector start around 15psi

what are you using for engine manamement

i am going to wager a SAFC

i read a few posts when i was considering that route that the SAFC is only good up until 440cc injectors

If you went to the megasquirt those would be no problem and you could use the oem fuel pressure

the easiest way to get the correct pressure is to get a pocketlogger or wideband AF meter and check your air fuel ratio at idle once everything is warmed up.

your should be running 14.5:1 on a wideband or if you are using a pocketlogger your short term fuel trims should be as close to zero as possible

 

[XMasta19]

yeah, the SAFC can only adjust +/- 50%...so maybe they couldn't tune it correctly with those big injectors

 

[BigRand]

I've seen the SAFC handle that, however I just realized you said you have low impedance 550cc injectors.....if that is the case, mabe you should have someone check your resistor box. That could be a big deal.

 

[clipsit]

Thanks guys. I fixed the idle surge. Just the IAC valve, but still high idle. Around 1400-2000 RPM!!!

 

[baxsom]

sounds like vacuum leak

test your IAC with a volt meter to make sure it has the correct resistance

build a boost leak tester or start spraying carb cleaner around the engine

to find it

oh yeah and low impedence

NT ecu's must have high impedience or it will burn out the ecu

 

[clipsit]

NT ecu's must have high impedience or it will burn out the ecu

So I need a resistor pack then...right? The injectors are RC-PL8-550, meaning they are low impedance/low resistance, being 2.5-3 ohms and 43PSIg. They are also Peak and Hold. I hope this helps anyone help me.

 

[XMasta19]

not good...as said, we run high impedance saturated injectors...thus the need for a resistor pack to increase the resistance when using peak and hold injectors such as the 4g63 450's.

 

[baxsom]

look into these

http://www.racetronix.com/621031.html

they will make things a lot easier for you

 

[clipsit]

Thanks baxsom...I might try that, but for now I got the 550's in, so I got to make do. Thanks guys. As far as a resistor pack goes, would I just need one or one for each injector? Thanks.

 

[baxsom]

yes one for each injector

check each one with a ohm meter before you start the car
resistance should be 12-15 ohms

also remember that the safc for the NT eclipse can only take away fuel so it is maxed out on the negative side and you are still running rich

you are either going to have to lower the fp even more or go to the small injectors