help! IDLE=550 when STFT's go negative
Thread Starter
Joined: Mar 2003
Posts: 8,319
Likes: 1
From: North Carolina
help! IDLE=550 when STFT's go negative ok so i put new injectors on my car, now the idle is having trouble. they are 38# racetronix injectors
looking at the data logger (in hp tuners) the idle is great, then i see the short term fuel trims go dip down into the negative, and then the idle drops too to about 550. then it recovers to about 850 and smooths back to 775-800 and then it all happens again. i dont know if the car jsut needs time after the new injector and a few tuning sessions to learn this and get better or what. any comments or suggestions would be GREATLY appreciated because i have been trying to chase after this one since friday, and it starting to frustrate me.
any of you guys have this same problem after injectors? i used grease on the orings and gently put them in there, when driving the car seems to be ok, i wouldnt think there is a bad oring but is that a possibilty? what are some symptoms of that?
looking at the data logger (in hp tuners) the idle is great, then i see the short term fuel trims go dip down into the negative, and then the idle drops too to about 550. then it recovers to about 850 and smooths back to 775-800 and then it all happens again. i dont know if the car jsut needs time after the new injector and a few tuning sessions to learn this and get better or what. any comments or suggestions would be GREATLY appreciated because i have been trying to chase after this one since friday, and it starting to frustrate me.
any of you guys have this same problem after injectors? i used grease on the orings and gently put them in there, when driving the car seems to be ok, i wouldnt think there is a bad oring but is that a possibilty? what are some symptoms of that?
Thread Starter
Joined: Mar 2003
Posts: 8,319
Likes: 1
From: North Carolina
ok so from the looks of this and old logs, the o2s are not oscillating enough and it seems as if thats causing the problems, now why would this change from injectors only??
how long have you been running with the long tubes on?
You might try unhooking the O2s and MAF so you can use a wide-band and get the IFR and VE a little closer before trying to tune it in closed loop.
You still may be way off on the fuel.
I doubt it's an injector O-ring problem.
You might try unhooking the O2s and MAF so you can use a wide-band and get the IFR and VE a little closer before trying to tune it in closed loop.
You still may be way off on the fuel.
I doubt it's an injector O-ring problem.
Thread Starter
Joined: Mar 2003
Posts: 8,319
Likes: 1
From: North Carolina
i have been with long tubes for about a year and a half now. maf is off the car, the o2 sensors are brand new and would work fine before, i looked at the old logs i had. fueling at driving seems to be fine, its just that damn idle. seems like hte o2 sensors arent switching fast enough to keep the engine steady, now...how do i fix that??
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Originally Posted by WS6FirebirdTA00
i have been with long tubes for about a year and a half now. maf is off the car, the o2 sensors are brand new and would work fine before, i looked at the old logs i had. fueling at driving seems to be fine, its just that damn idle. seems like hte o2 sensors arent switching fast enough to keep the engine steady, now...how do i fix that??
OH, MAF unhookedI've never done that without also cutting the O2's off too.
Maybe try unhooking the O2s and just working with a wideband to get your VE table right.
Without the MAF the PCM is going to have trouble holding a steady & low idle speed... especially if you've got a larger than stock cam.
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