running lean
08-21-2009, 04:58 PM
#1
running lean
I dyno'ed the car a year back when it was stock (attached sheet).
i don't know why it was running lean, and i'm not sure what a stock 350z should be running the AFR at? and what possibly could cause this?
i've searched the forum for similar issue, but can't find any.
dyno'ed on DynoJet
vid of the dyno: http://www.youtube.com/watch?v=go4j2nz8k-I
i don't know why it was running lean, and i'm not sure what a stock 350z should be running the AFR at? and what possibly could cause this?
i've searched the forum for similar issue, but can't find any.
dyno'ed on DynoJet
vid of the dyno: http://www.youtube.com/watch?v=go4j2nz8k-I
Last edited by maXmood; 08-21-2009 at 04:59 PM.
08-22-2009, 01:29 PM
#3
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looking at the dyno it looks fine except it should be richer when you got WOT. Normal throttle usually keeps it about 14.7 best as possible.
General rule of thumb is to keep it below 12.0 at WOT all the way to redline. I keep mine about 11.3 above 6psi.
I'm not sure what the a/f is supposed to be on a stock car. If it's the stock ecu controlling it i guess you aren't responsible.
General rule of thumb is to keep it below 12.0 at WOT all the way to redline. I keep mine about 11.3 above 6psi.
I'm not sure what the a/f is supposed to be on a stock car. If it's the stock ecu controlling it i guess you aren't responsible.
08-22-2009, 02:08 PM
#4
so, basically you're saying that 14.7 is suppose to be normal (stock form). and at WOT, it should be richer than 14.
altho i thought 11 is rich, does that mean 12 is suppose to be the best in all situations (including FI setups)?
on a side note, i'm getting an HFC and an exhaust installed soon, and i'm sure i'll be running pretty lean. shouldn't the ECU be able to refine the parameters for a proper mixture?
altho i thought 11 is rich, does that mean 12 is suppose to be the best in all situations (including FI setups)?
on a side note, i'm getting an HFC and an exhaust installed soon, and i'm sure i'll be running pretty lean. shouldn't the ECU be able to refine the parameters for a proper mixture?
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08-22-2009, 08:54 PM
#9
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stock ecu
and when you add your hfc's and other stuff the ecu should automatically adjust for the needed fuel. That's why there are 4 o2 sensors on the car. This works to an extent. A retune would provide the most power out of the situation.
and when you add your hfc's and other stuff the ecu should automatically adjust for the needed fuel. That's why there are 4 o2 sensors on the car. This works to an extent. A retune would provide the most power out of the situation.
08-22-2009, 10:04 PM
#10
i mean, since this car was imported from the US, the ECU is set to burn the fuel @ a certain rate (set in the ECU for the US product). and since we have a different octane level here, it won't be able to burn the fuel at the same rate. that could be the reason making it lean.
am i making any sense?
08-23-2009, 04:25 AM
#11
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i don't think octane would be the reason, but a difference in fuel could definitely be the reason.
did your elevation change drastically? that could also change.
You might want to take the battery cable off of the battery which allows the ecu to reset. It will take off the memory of your fuel trims and "relearn" your driving.
Judging by what everyone else is saying your a/f isn't bad at all for NA. I'm not familiar with the a/f ratio of this car when it's not boosted.
did your elevation change drastically? that could also change.
You might want to take the battery cable off of the battery which allows the ecu to reset. It will take off the memory of your fuel trims and "relearn" your driving.
Judging by what everyone else is saying your a/f isn't bad at all for NA. I'm not familiar with the a/f ratio of this car when it's not boosted.
08-23-2009, 05:33 AM
#12
actually we're at sea level in terms of elevation. i mean, we're a small island surrounded with sea from every direction, and not a single mountain. humidity is always high and summer heat is like 6 months a year.
in terms of octane level, we're running 95-96RON (which is 90-91AKI) at the stations.
i'll defo. reset the ecu once i get both mods installed.
in terms of octane level, we're running 95-96RON (which is 90-91AKI) at the stations.
i'll defo. reset the ecu once i get both mods installed.
08-23-2009, 07:39 AM
#13
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also, i just remembered. If you have an exhaust system that isn't "straight through" design doesn't taking a tailpipe reading show on the lean side of a/f? I could have swore someone mentioned that it did.
I don't think the octane is the problem with the a/f. If it has a higher ethanol content it might not be supplying enough fuel per unit volume or the a/f reading on the o2 sensor could be off due to the odd mixture of fuel.
I don't think the octane is the problem with the a/f. If it has a higher ethanol content it might not be supplying enough fuel per unit volume or the a/f reading on the o2 sensor could be off due to the odd mixture of fuel.
08-23-2009, 08:47 AM
#14
any chance it could be the injectors not pumping properly/clogged? since the normal AFR @ 14.7, the injectors are spraying the minimum gas required, but at WOT the injectors should be spraying at a higher rate, and if the injectors are clogged, the AFR will be lean since the air will be more than fuel.
is that possible?
is that possible?
08-23-2009, 09:42 AM
#16
