Need brainstorm help in why car is rich, no changes in mods
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From: Northwest side of Chicago
Need brainstorm help in why car is rich, no changes in mods So I had my car dyno tuned in February. It was tuned at 11.8afr from 10 to 19ish psi.
Now with no changed to anything,tune or mods my wb is reading 10.9 11.0.
Fuel pressure gauge in car reads the same.
Im going to rule out the wb hopefully tomorrow by trying a proven good one and il try another fuel pressure gauge too.
Other then that what could it be?
If my springs wore out causing valve float would that cause a rich or lean reading?
I tried swapping plugs and lowering gap from .028 to .023. No change.
It holds boost very steady and I checked for leaks.
Not sure on ethanol content at the time of the tune but i live in Chicago so it might have been a winter blend. Now its e10.
Thanks
Alex
Ps,in other threads i speak of installing a Meth kit. I turned that off and reverted to the non metg tune. This is straight 93 octane
Now with no changed to anything,tune or mods my wb is reading 10.9 11.0.
Fuel pressure gauge in car reads the same.
Im going to rule out the wb hopefully tomorrow by trying a proven good one and il try another fuel pressure gauge too.
Other then that what could it be?
If my springs wore out causing valve float would that cause a rich or lean reading?
I tried swapping plugs and lowering gap from .028 to .023. No change.
It holds boost very steady and I checked for leaks.
Not sure on ethanol content at the time of the tune but i live in Chicago so it might have been a winter blend. Now its e10.
Thanks
Alex
Ps,in other threads i speak of installing a Meth kit. I turned that off and reverted to the non metg tune. This is straight 93 octane
Thread Starter
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From: Northwest side of Chicago
Ruled out wideband and fuel pressure today. As soon as it goes in pe even with little to no boost it goes to 11.0afr. Was 11.7 -11.8 before.
Im gOing to swap valve springs but i doubt that will do anything.
Im gOing to swap valve springs but i doubt that will do anything.
Thread Starter
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From: Northwest side of Chicago
I didn't give up on the meth but id like to figure this issue out before i add to the equAtion. I don't want to change the tune, there isnt a reason i should have to. That would be a bandiad type fix if there is a real issue
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FormerVendor
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From: WWW.SPEEDINC.COM
LTFT's are disabled so no carryover into wot.
I would change the valvesprings as it seems you need them anyway by looking at the dyno graph. After that get it back on the dyno and check it out. (I think you will be wasting your time otherwise)
May have just been a discrepancy between widebands at the time.
I would change the valvesprings as it seems you need them anyway by looking at the dyno graph. After that get it back on the dyno and check it out. (I think you will be wasting your time otherwise)
May have just been a discrepancy between widebands at the time.
Thread Starter
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Springs are getting done for sure, i have the install height checker and push rod length checker now. Just still seems odd for it to go so rich for no reason.
What was the temperature when you got it dyno tuned? February in Chicago is cold... Cold air is dense air, so it'll use more of the available fuel in the cylinder. The speed density model doesn't take temperature into account like a MAF will...
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From: Norn Iron
Check any air temperature compensations or any other compensations that may be applied
Check datalogs to see if injector pulsewidths are much different from before until now which would account for more fuel.
Valve float, or anything that would allow excess air into the exhaust would cause an apparent lean condition ( although it would not be lean )
However, in cases like this and where you have closed loop fuel control enabled, this false reading can end up adding more fuel creating all sorts of problems.
But check actual injector pulse widths. That will tell you if the ecu is opening the injector the same as before, or longer than before
Check datalogs to see if injector pulsewidths are much different from before until now which would account for more fuel.
Valve float, or anything that would allow excess air into the exhaust would cause an apparent lean condition ( although it would not be lean )
However, in cases like this and where you have closed loop fuel control enabled, this false reading can end up adding more fuel creating all sorts of problems.
But check actual injector pulse widths. That will tell you if the ecu is opening the injector the same as before, or longer than before
Last edited by stevieturbo; Sep 11, 2013 at 05:15 PM.
Thread Starter
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From: Northwest side of Chicago
True it is pretty hot here not and really humid. That very well could be it, I didn't think temp would make almost a point difference in afr. Maybe I should have a spring and summer tune.
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From: Norn Iron
You shouldnt need a different tune.
Air temp compensations should cover this.. Although I'm not a fan of following what physics would state. It's ok reducing fuel with temperature up to a point, but when charge temps get higher than desired, I'm quite happy for it to get rich again.
Either way, check actual injector pulsewidths. If these are the same as before, yet mixtures vastly different, something is up.
Assuming same boost levels etc etc
Injector pulse width would be a good way to figure it out. There is no method of compensating for air temperature without a MAF, so the AFR can be expected to change with temp in SD mode. Better rich than lean, though.