lean at cruise? helps?
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From: kentucky
lean at cruise? helps?
my car is running lean
good idle afr but lean cruise. it has 650cc in the secondaries and 550cc in the primarys, using the stock ecu for the break in. is there any way i can fatten up the cruise?? no emissions on the car ect.
good idle afr but lean cruise. it has 650cc in the secondaries and 550cc in the primarys, using the stock ecu for the break in. is there any way i can fatten up the cruise?? no emissions on the car ect.
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Thread Starter
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Joined: May 2007
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From: kentucky
wideband.
idle is 11-12 afr
cruise is 15-17afr 10 psi vac
then closer to 0 on the vac/boost gauge is 14afr
^ all of that is under a vac
Joined: Mar 2001
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From: https://www2.mazda.com/en/100th/
the 15-17afr... is that occuring during deceleration or very low throttle? you said 10psi vac, that's 20 inches mercury. That's a lot of vac for cruising and indicates to me that the engine is under very little load. AFR in the 14's at 0psi isn't uncommon. My engine did that on stock ECU. The engine can stay in closed loop under part throttle boost. You could hit a couple psi part throttle and still be between 14:1 and 15:1 until certain conditions are met.
I don't know the specific closed loop/open loop logic on the FC but on other AFM/MAF based cars there is usually a max rpm trigger, a throttle position trigger, a load (some function of airflow divided by rpm) trigger, and often a delay counter. This is to keep fuel consumption down. So if you give it part throttle, it will wait until the necessary conditions are reached, then begin incrementing the delay counter. When the counter is maxed out it will go open loop and AFR's will richen up.
I don't know the specific closed loop/open loop logic on the FC but on other AFM/MAF based cars there is usually a max rpm trigger, a throttle position trigger, a load (some function of airflow divided by rpm) trigger, and often a delay counter. This is to keep fuel consumption down. So if you give it part throttle, it will wait until the necessary conditions are reached, then begin incrementing the delay counter. When the counter is maxed out it will go open loop and AFR's will richen up.
Thread Starter
Senior Member
Joined: May 2007
Posts: 720
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From: kentucky
the 15-17afr... is that occuring during deceleration or very low throttle? you said 10psi vac, that's 20 inches mercury. That's a lot of vac for cruising and indicates to me that the engine is under very little load. AFR in the 14's at 0psi isn't uncommon. My engine did that on stock ECU. The engine can stay in closed loop under part throttle boost. You could hit a couple psi part throttle and still be between 14:1 and 15:1 until certain conditions are met.
I don't know the specific closed loop/open loop logic on the FC but on other AFM/MAF based cars there is usually a max rpm trigger, a throttle position trigger, a load (some function of airflow divided by rpm) trigger, and often a delay counter. This is to keep fuel consumption down. So if you give it part throttle, it will wait until the necessary conditions are reached, then begin incrementing the delay counter. When the counter is maxed out it will go open loop and AFR's will richen up.
I don't know the specific closed loop/open loop logic on the FC but on other AFM/MAF based cars there is usually a max rpm trigger, a throttle position trigger, a load (some function of airflow divided by rpm) trigger, and often a delay counter. This is to keep fuel consumption down. So if you give it part throttle, it will wait until the necessary conditions are reached, then begin incrementing the delay counter. When the counter is maxed out it will go open loop and AFR's will richen up.
Hookt UP
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From: Sacramento
@arghx
you seem to be versed in this particular issue. I have hesitation on light throttle. Will climb to 16-17afr then correct and be on with business. I’m willing to pay for the remedy! It Can happen at any rpm but on very light throttle on the tip in. I’m running a sprint re, ported and built 13b with 4x id1000. Cars been tuned 3x, afrs are fine otherwise, fine under boost but I can’t seem to figure out the hesitation. tried a brand new tps. Same thing. Overtime I’ve replaced the fuel pump, filter, and cleaned the injectors. -6 AN feed and return. Voltage is good(14.4v). Fuel pressure is good(aeromotive fpr). 43.5psi. Any and all help is aprreciated.
you seem to be versed in this particular issue. I have hesitation on light throttle. Will climb to 16-17afr then correct and be on with business. I’m willing to pay for the remedy! It Can happen at any rpm but on very light throttle on the tip in. I’m running a sprint re, ported and built 13b with 4x id1000. Cars been tuned 3x, afrs are fine otherwise, fine under boost but I can’t seem to figure out the hesitation. tried a brand new tps. Same thing. Overtime I’ve replaced the fuel pump, filter, and cleaned the injectors. -6 AN feed and return. Voltage is good(14.4v). Fuel pressure is good(aeromotive fpr). 43.5psi. Any and all help is aprreciated.
Joined: Mar 2001
Posts: 31,833
Likes: 3,232
From: https://www2.mazda.com/en/100th/
@arghx
you seem to be versed in this particular issue. I have hesitation on light throttle. Will climb to 16-17afr then correct and be on with business. I’m willing to pay for the remedy! It Can happen at any rpm but on very light throttle on the tip in. I’m running a sprint re, ported and built 13b with 4x id1000. Cars been tuned 3x, afrs are fine otherwise, fine under boost but I can’t seem to figure out the hesitation. tried a brand new tps. Same thing. Overtime I’ve replaced the fuel pump, filter, and cleaned the injectors. -6 AN feed and return. Voltage is good(14.4v). Fuel pressure is good(aeromotive fpr). 43.5psi. Any and all help is aprreciated.
you seem to be versed in this particular issue. I have hesitation on light throttle. Will climb to 16-17afr then correct and be on with business. I’m willing to pay for the remedy! It Can happen at any rpm but on very light throttle on the tip in. I’m running a sprint re, ported and built 13b with 4x id1000. Cars been tuned 3x, afrs are fine otherwise, fine under boost but I can’t seem to figure out the hesitation. tried a brand new tps. Same thing. Overtime I’ve replaced the fuel pump, filter, and cleaned the injectors. -6 AN feed and return. Voltage is good(14.4v). Fuel pressure is good(aeromotive fpr). 43.5psi. Any and all help is aprreciated.
Assuming no mechanical problems, you would need to take some datalogs and tune the lean area. Ask the guy who tuned the car. It's either the actual portion of the fuel map or acceleration enrichment as j9fd3s indicated.
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