LT1 running 24x efi swap, hesitation, stumlbling
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97 lt1 camaro, 6 speed. Full bolt ons, heads/cam/intake, 37lb injectors, racetronix fuel pump kit. bla bla bla
So i appear to have the afr holding a steady 12.9-13.1 at wot. So thats good. Might lean it out a touch more, just to see. The original tune was setup to command 12.2 at wot. I pretty much moved it a whole point. HUGE difference. Pulls much harder now at wot.
Im still having a slight off idle/ part throttle tuning conundrum though. At times, ill be slowly trying to accelerate and ill notice some bucking, then the wideband goes lean most of the time, like 17-19 lean. If i put it to the floor, it clears up and is fine. I originally though i was runnning too lean on part throttle tables, until today. Today it did the same thing but was stayed within 14-16 on the wideband guage as far as i could tell. I was also pretty quick to try and correct the issue however
It stays around 14.5-15.2 while cruising part throttle, and on the highway in 6th at about 70 mph.
Does the same thing on the highway also, but without the going lean on the wideband as far as i can tell, but again i usually just tap it to the floor right away and fine.
Holding a steady 1600 ish rpm, driving fine then out of no where starts to surge slightly. If i put more into it, but not enough to get into the PE tables (wot) then it gets a little worse and will actually cough through the intake. This is what makes me thing its running to lean at part throttle.
Suggestions?
Im going to try and get a data log of JUST the issue at hand, unless otherwise requested.
EDIT: Knock sensor was throwing a code for low input. Just finished changing the knock sensor and both o2s as i had one reading quite a bit slower then the other
So i appear to have the afr holding a steady 12.9-13.1 at wot. So thats good. Might lean it out a touch more, just to see. The original tune was setup to command 12.2 at wot. I pretty much moved it a whole point. HUGE difference. Pulls much harder now at wot.
Im still having a slight off idle/ part throttle tuning conundrum though. At times, ill be slowly trying to accelerate and ill notice some bucking, then the wideband goes lean most of the time, like 17-19 lean. If i put it to the floor, it clears up and is fine. I originally though i was runnning too lean on part throttle tables, until today. Today it did the same thing but was stayed within 14-16 on the wideband guage as far as i could tell. I was also pretty quick to try and correct the issue however
It stays around 14.5-15.2 while cruising part throttle, and on the highway in 6th at about 70 mph.
Does the same thing on the highway also, but without the going lean on the wideband as far as i can tell, but again i usually just tap it to the floor right away and fine.
Holding a steady 1600 ish rpm, driving fine then out of no where starts to surge slightly. If i put more into it, but not enough to get into the PE tables (wot) then it gets a little worse and will actually cough through the intake. This is what makes me thing its running to lean at part throttle.
Suggestions?
Im going to try and get a data log of JUST the issue at hand, unless otherwise requested.
EDIT: Knock sensor was throwing a code for low input. Just finished changing the knock sensor and both o2s as i had one reading quite a bit slower then the other
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I'm interested in what it ends up being, mine does sorta the same thing, but tends to do it more when the car is cold. I'll go for the first 1-2 shift in the morning and the wideband reads stupid lean, then it like coughs and goes rich and the car resumes accelerating. Is it almost like a pause where the motor seems like it isn't running and then it spits back to life? Other times though no issues at all. I did some interstate driving today and had no problems, so I'm not plagued all the time like you are having.
Running a 24x setup on LT1 car also.
Running a 24x setup on LT1 car also.
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Just rewrote calibration only and took er for a spin. Moves like a bastard now without issue. I still have a slight idle issue however, but i have a feeling thats iac related. idle likes to hang sometimes. Also dips down past desired idle after revving up. Just not sure which tables i should be adjusting for that. Thats the problem i have. I know what id like to change/do to see if it fixes something, i just dont know which table to use to do so.
Revised tune, and log.
Last edited by 97lt1camaro; 07-24-2011 at 10:55 PM.
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I'm interested in what it ends up being, mine does sorta the same thing, but tends to do it more when the car is cold. I'll go for the first 1-2 shift in the morning and the wideband reads stupid lean, then it like coughs and goes rich and the car resumes accelerating. Is it almost like a pause where the motor seems like it isn't running and then it spits back to life? Other times though no issues at all. I did some interstate driving today and had no problems, so I'm not plagued all the time like you are having.
Running a 24x setup on LT1 car also.
Running a 24x setup on LT1 car also.
Last edited by 97lt1camaro; 07-24-2011 at 10:55 PM.
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If im not mistaken at wot im getting 4* of knock while the motor is only commanding about 25 timing. Timing seems a little low for a lt1 at wot does it not?
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I am going to replace my o2 sensors this week also as Saturday when the tuner was looking at it, the o2s weren't really showing any action, then the driver side would pull 12% and the passenger side was trying to add 8%, in fuel trims if I remember correctly. He was telling me you should see action while scanning, that it should be making minor adjustments all the time. Mine were just kind of dead, then would pull those numbers, then at idle would zero out.
97lt1camaro, is your TPS zeroing out? That is an issue I had with my car, it was stalling out almost all the time when I was coming to a stop. The TPS was reading like 2.5 and the IAC counts were up around 95. Had to trim the screw holes on the tps and tilt it forward slightly to zero out, now IAC counts are down where they belong, no more stalling or RPM dipping below 800 rpm.
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I have EFI Live but I haven't had the time to figure out how to use it yet. Well Doc at EFI Alchemy showed me how to load the default PIDs so I can scan but haven't had time. So I have no idea how to make a copy of the tune file either.
I am going to replace my o2 sensors this week also as Saturday when the tuner was looking at it, the o2s weren't really showing any action, then the driver side would pull 12% and the passenger side was trying to add 8%, in fuel trims if I remember correctly. He was telling me you should see action while scanning, that it should be making minor adjustments all the time. Mine were just kind of dead, then would pull those numbers, then at idle would zero out.
97lt1camaro, is your TPS zeroing out? That is an issue I had with my car, it was stalling out almost all the time when I was coming to a stop. The TPS was reading like 2.5 and the IAC counts were up around 95. Had to trim the screw holes on the tps and tilt it forward slightly to zero out, now IAC counts are down where they belong, no more stalling or RPM dipping below 800 rpm.
I am going to replace my o2 sensors this week also as Saturday when the tuner was looking at it, the o2s weren't really showing any action, then the driver side would pull 12% and the passenger side was trying to add 8%, in fuel trims if I remember correctly. He was telling me you should see action while scanning, that it should be making minor adjustments all the time. Mine were just kind of dead, then would pull those numbers, then at idle would zero out.
97lt1camaro, is your TPS zeroing out? That is an issue I had with my car, it was stalling out almost all the time when I was coming to a stop. The TPS was reading like 2.5 and the IAC counts were up around 95. Had to trim the screw holes on the tps and tilt it forward slightly to zero out, now IAC counts are down where they belong, no more stalling or RPM dipping below 800 rpm.
Yea the tps is zeroing out, my IAC are through the roof most of the time though. I had it running yesterday after i fixed the injector bank and commanded 850 idle in the pcm while running and it seemed fine. My iac counts were down in the 40-60 range most of the time. So im going to adjust it tonight.
It should be at 60-70 with a cammed car.
1) You will want to monitor your IAC, Idle Speed, throttle position voltage and your throttle position %.
2) With the key in the ON position, adjust your tb set screw until your throttle position is 2%.
3) Turn your key to the OFF position.
4) Unplug your Throttle Position Sensor (TPS).
5) Turn your key to the ON position for a few
seconds, and then OFF again.
6) Plug in the TPS and then turn your key to the ON position and restart logging. Your throttle position will now be reset to 0 degrees and about .45-.55 volts. Any higher can put you into the wrong fueling cell.
7) Start your engine, if you are not at your desired IAC position redo the above procedures in smaller increments.
8) If your TPS voltage should be between .45 and .55 volts you may need to drill the mounting holes a little bigger and remove the
locator tab so you can make an adjustment.
Courtesy of 69lt1bird off hptuners
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That is what was driving the tuner crazy he was like this thing should TPS reset, it should go to zero! We had to physically set it to zero to zero it out. It was a replacement TPS though, an original TPS borrowed from another car real quick for trouble shooting got it to show .04. I was scratching my head I told him it was a new IAC and TPS so I had no idea, but now we know.
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Im Ben Charles on the HP tuner forum 97lt1camaro. I will look at your tune in a little.
Whats your mods??
You running an stock fuel system at the rail or adjustable vacuum referenced FPR?
You have a WB? If so post your config as well so I can look at your scanner data the same as you.
Your commanding 13-13.1 AFR at WOT by your PE table, depending on mods, may make more power around 12.5-12.8 AFR.
Whats your mods??
You running an stock fuel system at the rail or adjustable vacuum referenced FPR?
You have a WB? If so post your config as well so I can look at your scanner data the same as you.
Your commanding 13-13.1 AFR at WOT by your PE table, depending on mods, may make more power around 12.5-12.8 AFR.
Last edited by T/A KID; 07-25-2011 at 03:31 PM.
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Im Ben Charles on the HP tuner forum 97lt1camaro. I will look at your tune in a little.
Whats your mods??
You running an stock fuel system at the rail or adjustable vacuum referenced FPR?
You have a WB? If so post your config as well so I can look at your scanner data the same as you.
Your commanding 13-13.1 AFR at WOT by your PE table, depending on mods, may make more power around 12.5-12.8 AFR.
Whats your mods??
You running an stock fuel system at the rail or adjustable vacuum referenced FPR?
You have a WB? If so post your config as well so I can look at your scanner data the same as you.
Your commanding 13-13.1 AFR at WOT by your PE table, depending on mods, may make more power around 12.5-12.8 AFR.
Stock fuel system as far as pressure/regulator goes.
- Le2 heads, comp 218/224 camshaft, ported/polished le intake. K/n cai, 58 bbk throttle body(back iac area made like stock/seperated from plenum.) 37lb injectors, 1.6 r/r, efi 24x obviously, magnaflow, pacesetter lts, racentronix fuel pump/wiring kit,stock bottom end, Uh think thats all .
Not sure on posting the config, i havent saved a config yet. Ive just been manually adding them everytime i log haha. All ive added was iac requested/actual and the wideband under user defined.
Car feels pretty wicked right now, but ill knock it down a bit and see whats going on.
I keep getting a code for P0332 (knock sensor low input) . I replaced the knock sensor, all the wiring is brand new and safe still.
Should i even be worrying about this? I know the ls1 uses 2 sensors, so im wondering if thats why its throwing the code in the first place?
Last edited by 97lt1camaro; 07-25-2011 at 10:00 PM.
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I don't know what to tell you about the knock sensor? I run 1 as well in the factory LT1 location without any codes or problems.
How is the idle? Do you know your IAC counts when warm?
How is the idle? Do you know your IAC counts when warm?
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Would you be able to check to see if your P0332 code is tuned out in your tune? Would be greatly appreciated.
idles fine once it warms up, it does hang up a bit alot of the time. First start every day the car almost stalls out then comes back up slowly. Runs real lean at start up., like 17afr lean.
The iac are high, ive seen it requesting upwards of 130-170 at warm idle before. I still need to reset the tps/iac after i adjust the throttle body some. IM hoping that will get rid of the idle hanging up.
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Are you willing to start over with a new base tune?
I know of a setting that will help you out, but I can't do it for free with your tune. I can either give you a new base calibration with the setting changed or I could spend the money on the credits and make the adjustment to your tune
email me for details
caleditor@pcmcalibrators.com
I know of a setting that will help you out, but I can't do it for free with your tune. I can either give you a new base calibration with the setting changed or I could spend the money on the credits and make the adjustment to your tune
email me for details
caleditor@pcmcalibrators.com
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Well as an update on my end of this issue, replaced o2's today, now the wideband shows 13.5-16.5 at part throttle cruising instead of stupid lean. Not sure how it will run completely cold tomorrow. Haven't scanned it yet, but looks like its trimming out better now so long as the wideband isn't lying to me.
Haven't switched bank select, hell I have no idea where to even start anyway. Maybe I'm lucky and my o2s really were getting lazy.
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Well as an update on my end of this issue, replaced o2's today, now the wideband shows 13.5-16.5 at part throttle cruising instead of stupid lean. Not sure how it will run completely cold tomorrow. Haven't scanned it yet, but looks like its trimming out better now so long as the wideband isn't lying to me.
Haven't switched bank select, hell I have no idea where to even start anyway. Maybe I'm lucky and my o2s really were getting lazy.
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Made a huge difference on how my car drove, i dont even have a stumble off take off anymore.
Just trying to get rid of a hanging idle once in a while and a shitty first start in the morning. Starts right up, but almost dies out then comes back to idle.