tuners please help, air fuel ratio!!!!!!!
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tuners please help, air fuel ratio!!!!!!!
I just put on dual exhaust because the single was inefficient, before I put the dual exhaust on, my afr was 12.8 at wot. Now my afr is 13.7 at wot. So my question is do I have to retune my car or is my injectors or fuel pump not enough? My car is a 2000 ws6 ta. Please respond your info would be appreciated. I do have a wideband o2 gage.
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my heads flow 300/200 and my old single exhaust was a flowmaster cat back with only a 2 1/2 pipe going over the rear axel, now i have dual 2 1/2 dumping by the rear end
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Question how you get that number, first off. Widebands
lie for various reasons. And sometimes they don't.
One overgapped plug could misfire enough at WOT,
to jack the reading lean but be fine at lesser cylinder
pressure. And this would have nothing to do with
fueling.
One injector with a little too much silt in the screen,
would be truly lean in proportion to fuel flow. But
have nothing to do with any tune settings / data,
and maybe not bother anything at lower throttle
(enough to notice, yet).
Fuel pressure fade increases over time, again it
will be demand-proportional. Fuel filter, pump
age & wiring, etc.
lie for various reasons. And sometimes they don't.
One overgapped plug could misfire enough at WOT,
to jack the reading lean but be fine at lesser cylinder
pressure. And this would have nothing to do with
fueling.
One injector with a little too much silt in the screen,
would be truly lean in proportion to fuel flow. But
have nothing to do with any tune settings / data,
and maybe not bother anything at lower throttle
(enough to notice, yet).
Fuel pressure fade increases over time, again it
will be demand-proportional. Fuel filter, pump
age & wiring, etc.
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this is my first ls1 build and am trying to iron out all of the bugs. this is a new bottom end with heads that flow 300/200 with a comp cam 228/230 571/573 on a 112 look at my sig for all other details. i had it tuned and all my afr was 12.8 at wot. but it didnt have the power it should so i looked at the exhaust and noticed i overlooked the single 2 1/2 single pipe and looked at exhaust forum. it stated that a single 2 1/2 was too small for my build. thus i changed it and the motor feels like its breathing like it needs to. that being said its moving alot more air out of the motor so its pulling more air in like it should. so, do i need to add more fuel at wot?
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yes its going thru the maf. so your saying the maf is set to run at 12.8 at wot then when the motor flows more air the maf will add more fuel for the more air thats its getting.
#10
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yes its going thru the maf. so your saying the maf is set to run at 12.8 at wot then when the motor flows more air the maf will add more fuel for the more air thats its getting.
You can't tune your car at WOT with just a MAF...
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i am mainly asking to understand how this system works. i guess i need to send my computer back to my tuner to tune the fuel in. so my injectors and fuel pump should be sufficient?
#13
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If the MAF output in HZ increases with more airflow which it should unless the sensor is defective, the PCM will add more fuel because of the increase in airflow.
#15
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And if the MAF is calibrated correctly it should measure the increased airflow for any increase. Why would it not? Otherwise how would it measure an increase in airflow from just an increase in rpm?
So if it's not tune related, then the MAF would not know to add in more air since it can't see what the output is. As far as the MAF knows, it's putting in enough fuel for 12.8 AFR. What comes out the exhaust and is read by the wb @ 13.7 the MAF has no clue about, so the MAF would not be adding extra fuel as you mentioned in your previous post.
#16
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So if it's not tune related, then the MAF would not know to add in more air since it can't see what the output is. As far as the MAF knows, it's putting in enough fuel for 12.8 AFR. What comes out the exhaust and is read by the wb @ 13.7 the MAF has no clue about, so the MAF would not be adding extra fuel as you mentioned in your previous post.
#17
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MAFs don't add air based on anything from any other sensor or wideband.
They don't add air from any sensor, so given that the amount of air entering the engine is the same yet the final output is different suggests and issue in the exhaust portion misleading the wideband.
If more air was indeed drawn through the intake then yes the MAF would adjust accordingly (to a certain point). But there isn't, so the MAF would not be adjusting anything.
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I finally drove my car today, i had it parked since last weekend, because i seen the a/f at 13.7. I dont want to hurt my new motor. there must had been a glitch in the wideband . i had been worried for nothing because i drove it to work today and got on it and the a/f was 13.1. i read your post and kept thinking there is no way it could have gone that lean, but i have had it on a dyno before and the wideband was correct, and was worried it was lean and did not want to damage my motor.i got on it quite a few times and the a/f was consistant today. thanks for the advise, didnt want to chance the motor. because i know nothing about tuning.