Settings A/F on EFI

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Norfork, AR
I am running a .030 over 383 with MSD, 484 cam, Performer Al heads, headers, 3.91 rearmed, 727 trans. My problem is with he EFI, I think. This sucker sucks up the gas. I can smell it running rich at idle and suspect it is doing he same while cruising. I suspect I am getting only 6 miles per gallon of premium non alcohol 93 octane. The A/F ratios are those that FAST EFI EZ says to start with. I want to increase the ratio at idle and at cruise. How much do I dare go. I would like to bracket the best set point. By that I mean I would like to set the a/f at the max and then drop back from there to find the best setting. Sneaking up on a setting may not give me the feel for what it is like at the max. Can anyone provide some advise? Thank you for any and all input.
 
14.5 seems optimal from most of the info I have seen here and elsewhere. After that you will have to be careful about detonation issues if your timing is not spot on. I try to stay around 13.5-14 to be safe. I am running a carburetor though.
 
14.5 seems optimal from most of the info I have seen here and elsewhere. After that you will have to be careful about detonation issues if your timing is not spot on. I try to stay around 13.5-14 to be safe. I am running a carburetor though.
Your recommendation is by the book and I have mine set at 13.6 at idle and 14.3 at cruise, but I believe it is running rich at those settings.
 
The factory recommended settings have a fairly large safety margin built into them, in other words they are intentionally on the rich side.
Do you have a wideband O2 sensor that you can read the A/F ratio while driving? If not, tuning it is going to be difficult, and maybe a bit risky.
For on the highway, level ground, part throttle cruise, between 15.0 and 15.5 are going to work well. Idle mixture depends on a lot of things, so I can't give you a solid setting there, but generally it's between 12.8 and 13.5.
Wide open throttle is usually around 12.0 to 12.5.
Don't let the AFR stay any leaner than about 16.8 for any length of time.
 
I am running a .030 over 383 with MSD, 484 cam, Performer Al heads, headers, 3.91 rearmed, 727 trans. My problem is with he EFI, I think. This sucker sucks up the gas. I can smell it running rich at idle and suspect it is doing he same while cruising. I suspect I am getting only 6 miles per gallon of premium non alcohol 93 octane. The A/F ratios are those that FAST EFI EZ says to start with. I want to increase the ratio at idle and at cruise. How much do I dare go. I would like to bracket the best set point. By that I mean I would like to set the a/f at the max and then drop back from there to find the best setting. Sneaking up on a setting may not give me the feel for what it is like at the max. Can anyone provide some advise? Thank you for any and all input.

I have a fast 2.0 on my 505 , I have the a/f ratios about half way between the min and max recommended settings right now, timing 34 total all in at 3000 , (91 OCTANE NON ALCOHOL DOG PISS" , still not done w/ it. Its getting way better than 6 mpg, haven't checked for sure, but it seems to get better mileage than my "new 440 4 speed dodge did , back in the day. I did have the total cruise timing out on the road at 50 , changed it to 45 , still messing w/ it in between rain storms ----which aint often around here this year !
I have the enrichment START UP setting 2 clicks richer than what is on the self tuning set up , need that for the tall intake I`m running , still have to give it one pedal before hitting the starter , to get it to start quickly , altho u aint supposed to have to do that .
Don't be afraid to lean it down a couple of clicks right off the bat , the self learning set up is rich / for safety reasons.
I had to go to a step hotter plug ------------ngk 6 . 3;73 rear gear w/ 29" tall tire out back , with a 3:91 , I`d run the tallest thing I could get under it for the street .----------Tell us what u come up with .
 
I have a fast 2.0 on my 505 , I have the a/f ratios about half way between the min and max recommended settings right now, timing 34 total all in at 3000 , (91 OCTANE NON ALCOHOL DOG PISS" , still not done w/ it. Its getting way better than 6 mpg, haven't checked for sure, but it seems to get better mileage than my "new 440 4 speed dodge did , back in the day. I did have the total cruise timing out on the road at 50 , changed it to 45 , still messing w/ it in between rain storms ----which aint often around here this year !
I have the enrichment START UP setting 2 clicks richer than what is on the self tuning set up , need that for the tall intake I`m running , still have to give it one pedal before hitting the starter , to get it to start quickly , altho u aint supposed to have to do that .
Don't be afraid to lean it down a couple of clicks right off the bat , the self learning set up is rich / for safety reasons.
I had to go to a step hotter plug ------------ngk 6 . 3;73 rear gear w/ 29" tall tire out back , with a 3:91 , I`d run the tallest thing I could get under it for the street .----------Tell us what u come up with .
Garry and Bob, thanks for the reply. That is just the information I was looking for. I don’t think I will go to the upper limits right now, but I will start at something like 13.8 at idle, 14.8 (maybe 15) at cruise and 12 at wot. I’ll let you know how your helping worked out. Bob, why the hotter plug?
 
I have a fast 2.0 on my 505 , I have the a/f ratios about half way between the min and max recommended settings right now, timing 34 total all in at 3000 , (91 OCTANE NON ALCOHOL DOG PISS" , still not done w/ it. Its getting way better than 6 mpg, haven't checked for sure, but it seems to get better mileage than my "new 440 4 speed dodge did , back in the day. I did have the total cruise timing out on the road at 50 , changed it to 45 , still messing w/ it in between rain storms ----which aint often around here this year !
I have the enrichment START UP setting 2 clicks richer than what is on the self tuning set up , need that for the tall intake I`m running , still have to give it one pedal before hitting the starter , to get it to start quickly , altho u aint supposed to have to do that .
Don't be afraid to lean it down a couple of clicks right off the bat , the self learning set up is rich / for safety reasons.
I had to go to a step hotter plug ------------ngk 6 . 3;73 rear gear w/ 29" tall tire out back , with a 3:91 , I`d run the tallest thing I could get under it for the street .----------Tell us what u come up with .
Garry and Bob, thanks for the reply. That is just the information I was looking for. I don’t think I will go to the upper limits right now, but I will start at something like 13.8 at idle, 14.8 (maybe 15) at cruise and 12 at wot. I’ll let you know how your helping worked out. Bob, why the hotter plug?

Was too cold , had trouble getting a decent plug reading . Still not where I want it to be tho . I`m at 12.6 at wide open throttle too , not many places to really test that on the street tho------------
 
I personally like to start on the lean side and gradually go richer just until it runs well (good response, no hesitation) but I have a wideband O2 sensor and know how to be careful if things are too lean (keep your foot off the gas!). I'd put it at 14:1 at idle and 15.5:1 at cruise and see what happens.

13.6:1 and 14.3:1 ARE rich... all modern cars with cat. converters target 14.7:1 at cruise and idle but that's with port fuel injection, the EZ-EFI is throttle body right?
 
I personally like to start on the lean side and gradually go richer just until it runs well (good response, no hesitation) but I have a wideband O2 sensor and know how to be careful if things are too lean (keep your foot off the gas!). I'd put it at 14:1 at idle and 15.5:1 at cruise and see what happens.

13.6:1 and 14.3:1 ARE rich... all modern cars with cat. converters target 14.7:1 at cruise and idle but that's with port fuel injection, the EZ-EFI is throttle body right?

LOL, a 505' dinosaur w/ throttle body, no cat.
 
LOL, a 505' dinosaur w/ throttle body, no cat.

I'm willing to bet since the OP has aluminum heads they should be a closed-chamber design and the compression should be at least 9:1...? In that case the burn rates are higher than with factory open-chamber heads and low compression meaning the engine will tolerate leaner mixtures than it would have stock. Just pointing that out for some peace of mind, everyone's scared of running lean but until you hit stumbling and misfiring it's really not hurting anything. I don't like the idea of running rich in any case except heavy load or WOT because you're just wasting fuel that's washing down your cylinders and actually wearing out your engine faster than needed.
 
I'm willing to bet since the OP has aluminum heads they should be a closed-chamber design and the compression should be at least 9:1...? In that case the burn rates are higher than with factory open-chamber heads and low compression meaning the engine will tolerate leaner mixtures than it would have stock. Just pointing that out for some peace of mind, everyone's scared of running lean but until you hit stumbling and misfiring it's really not hurting anything. I don't like the idea of running rich in any case except heavy load or WOT because you're just wasting fuel that's washing down your cylinders and actually wearing out your engine faster than needed.
Good point. The compression is 9.4:1 and does have Edelbrock Performer AL heads with headers. Your comments make me feel more comfortable moving to lean. What cruise speed would you recommend? I am running a 3.91 rear end, so my rpms will be higher than normal at any speed. and, yes, it is a throttle body efi.
 
Good point. The compression is 9.4:1 and does have Edelbrock Performer AL heads with headers. Your comments make me feel more comfortable moving to lean. What cruise speed would you recommend? I am running a 3.91 rear end, so my rpms will be higher than normal at any speed. and, yes, it is a throttle body efi.

Cruise speed, I'm not sure that mostly depends on what you can tolerate and what the speed limits are in your area. The 3.91s definitely won't help with gas mileage but you can do a lot better than single-digits. What kind of RPMs are you turning on the highway, and at what speed?
 
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