OPEN loop rough idle, smooth closed loop idle....?
03-28-2017, 04:38 PM
#1
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OPEN loop rough idle, smooth closed loop idle....? So I'm having problems with my LS1/T56 swapped second gen Camaro still....
it seems that the car is running better in CLOSED loop than open loop....weird
now I'm a rookie with fuel injection and still learning but soaking it up like a sponge so bear with me.
In open loop (outside temp in Ohio is roughly
60F today) the right bank mostly is acting up. The headers on that side read way below the left side in temperature according to my IR thermometer. If I wiggle the #6 injector it fluctuates. Sometimes the wiggling will cause it to idle bad, sometimes the wiggling causes it to idle smooth. The right side o2 is bouncing from .1 to .9 volts VERY slowly. The drivers side however seems to fluctuate rather consistently like a sine wave
Could it be that the car needs a time job with the short term fuel trims on that side? I have a scanner tool and can get measurements if need be.
Im thinking there is something wrong mechanically at this point. Over/undertorqued valve springs (I rebuilt the engine almost 3 years ago but I'm sure I torque them down correctly like everything else)
any guidance is appreciated!
it seems that the car is running better in CLOSED loop than open loop....weird
now I'm a rookie with fuel injection and still learning but soaking it up like a sponge so bear with me.
In open loop (outside temp in Ohio is roughly
60F today) the right bank mostly is acting up. The headers on that side read way below the left side in temperature according to my IR thermometer. If I wiggle the #6 injector it fluctuates. Sometimes the wiggling will cause it to idle bad, sometimes the wiggling causes it to idle smooth. The right side o2 is bouncing from .1 to .9 volts VERY slowly. The drivers side however seems to fluctuate rather consistently like a sine wave
Could it be that the car needs a time job with the short term fuel trims on that side? I have a scanner tool and can get measurements if need be.
Im thinking there is something wrong mechanically at this point. Over/undertorqued valve springs (I rebuilt the engine almost 3 years ago but I'm sure I torque them down correctly like everything else)
any guidance is appreciated!
03-28-2017, 08:31 PM
#2
Or your fuel injectors aren't firing? Or spark plugs aren't producing spark. Etc.
Or the O2 on that side is switching slow and hasn't tripped a code yet.
Work on fuel/spark first. Then move to electrical. Then move to the tune once all that is exhausted.
On non-flow-matched injectors, you can see a 5-10% fluctuations bank to bank. So I normally tune off Bank 2 with my wideband then check the STFTs on both banks. Typically Bank 2 is spot on and Bank 1 is richer 5-8%. So what I do is I will just go back to the VE table and add in 3-4% across the board so I'm within 3% on one side and within 2-5% on the other.
When I had flow-matched injectors, the difference was 1-2% between banks. So that might be something to look at as well once you get all the gremlins diagnosed.
Or the O2 on that side is switching slow and hasn't tripped a code yet.
Work on fuel/spark first. Then move to electrical. Then move to the tune once all that is exhausted.
On non-flow-matched injectors, you can see a 5-10% fluctuations bank to bank. So I normally tune off Bank 2 with my wideband then check the STFTs on both banks. Typically Bank 2 is spot on and Bank 1 is richer 5-8%. So what I do is I will just go back to the VE table and add in 3-4% across the board so I'm within 3% on one side and within 2-5% on the other.
When I had flow-matched injectors, the difference was 1-2% between banks. So that might be something to look at as well once you get all the gremlins diagnosed.
03-28-2017, 10:24 PM
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So I don't think it would be the spark or fuel injection. But it could be
Now you specifically mentioned non-flow matched injectors. Meaning cylinder specific? Because I noticed on the back on my injectors there are tiny printed numbers and they aren't the same for all 8 injectors. Could I have put injectors on the wrong sides/forward or aft?