AFR reading 22.4 when decelerating
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Junior User
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AFR reading 22.4 when decelerating
I have a 410 stroker recently built. I'm getting full lean when decelerating down hill. It seemed to be fine when I had the stock pump in the rear tank, once I switched to a new pump 255lph in the front it started to sometimes go full lean. It is confirmed by p0171 and 4 codes. Now that I have both front and rear on the new pump, the rear now does it too. Tried 2 different pumps for front, the latest one is from Quantum fuel with a pump module. It doesn't do it all the time but starting to get more frequent. I have a couple hundred miles on the engine so far. I might need to install a fuel pressure gauge to see if the pump is actually pumping enough pressure when it happens. Any ideas?
Fleet Mechanic
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From: MD
Fleet Mechanic
Joined: Feb 2007
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From: Mandan, ND
My Cobra pegs the AFR lean when decel. Seems normal to me, I get no codes. Car is highly modified.
Going down a hill, in gear, off throttle, the engine is just a big air pump. Why wouldn't it show lean?
I would guess your p0171 is not coming from decel...
Going down a hill, in gear, off throttle, the engine is just a big air pump. Why wouldn't it show lean?
I would guess your p0171 is not coming from decel...
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Did yours peg 22.4, max? It's as though the pump momentarily dies. It has happened a number of times and usually with the p0171 or p0174 right after. Not a coincidence. The first time it happened engine died and would not restart until i messed with the front pump after getting it towed, even tried the rear pump. The rear stock pump did not do it at all, it's only when i switched to the 255lph pumps. I'm wondering if it's something to do with the strategy being used, AGANN. I am using Tweecer. Tuner could not get the CFAK* to enable logging. It is not fully tuned yet so I'm just babying it for now. Hopefully when I install the fuel pressure gauge it will show an actual low pressure when it occurs.
Fleet Mechanic
Joined: Feb 2007
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From: Mandan, ND
Yes, my AFR gauge pegs max (22 something) on decel.
I have a 255lph in tank with 60lb S-D injectors. My setup has a Quarter horse and am running BE (database version).
Like I said above, I see this as normal behavior. My buddies Fox (modified 302) did it with QH/BE and does it with Terminator X.
Think about it this way...how would it be possible to get stoichiometric with throttle closed, RPMa (not idle) and little fuel being delivered?
I have a 255lph in tank with 60lb S-D injectors. My setup has a Quarter horse and am running BE (database version).
Like I said above, I see this as normal behavior. My buddies Fox (modified 302) did it with QH/BE and does it with Terminator X.
Think about it this way...how would it be possible to get stoichiometric with throttle closed, RPMa (not idle) and little fuel being delivered?
Fleet Mechanic
Joined: Feb 2007
Posts: 1,252
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From: Mandan, ND
Oh, side note...Terminator X is awesome! I am putting it on my 1967 project to run the 1994 460. They even make a Mod and Coyote Terminator X now, along with Terminator X Max that runs a tranny...
Way more simple than running a board on the stock computer trying to modify things Ford never intended to be modified...
Way more simple than running a board on the stock computer trying to modify things Ford never intended to be modified...
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Junior User
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I do agree with you there, and if it never trigged a lean condition I would be fine with it. I wonder if I can change what it sees as lean.
Yes, my AFR gauge pegs max (22 something) on decel.
I have a 255lph in tank with 60lb S-D injectors. My setup has a Quarter horse and am running BE (database version).
Like I said above, I see this as normal behavior. My buddies Fox (modified 302) did it with QH/BE and does it with Terminator X.
Think about it this way...how would it be possible to get stoichiometric with throttle closed, RPMa (not idle) and little fuel being delivered?
I have a 255lph in tank with 60lb S-D injectors. My setup has a Quarter horse and am running BE (database version).
Like I said above, I see this as normal behavior. My buddies Fox (modified 302) did it with QH/BE and does it with Terminator X.
Think about it this way...how would it be possible to get stoichiometric with throttle closed, RPMa (not idle) and little fuel being delivered?
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Don't you have to replace everything with terminator X? If i didn't have to get a controller for the trans I would've gone carb. Carbs make for a cleaner engine bay. EFI while nice is messy and even worse when the tuner can't figure out why he can't enable logging.
Oh, side note...Terminator X is awesome! I am putting it on my 1967 project to run the 1994 460. They even make a Mod and Coyote Terminator X now, along with Terminator X Max that runs a tranny...
Way more simple than running a board on the stock computer trying to modify things Ford never intended to be modified...
Way more simple than running a board on the stock computer trying to modify things Ford never intended to be modified...
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Cargo Master
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Oh yes, much cleaner. And all that nice fuel dilution, and generally worse mileage, not to mention the fuel saturation into the catalytic converter, and the extra emissions coming out the tailpipe. Oh yes, and having to swap the distributor out for something with mechanical and/or vacuum advance, to run properly. Makes perfect sense.
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Oh yes, much cleaner. And all that nice fuel dilution, and generally worse mileage, not to mention the fuel saturation into the catalytic converter, and the extra emissions coming out the tailpipe. Oh yes, and having to swap the distributor out for something with mechanical and/or vacuum advance, to run properly. Makes perfect sense.
. I have the HEI distributor, new in box. Heck I can't even get an Edelbrock EFI truck intake for the 5.8 in a timely manner. They just keep extending the ship date i had to cancel and modded a 302 intake to fit. Will take it to my local tuner if all else fails.
Cargo Master
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I had an old 4 banger ran great on carb. Not worried about emissions, we're all gonna die anyways . I have the HEI distributor, new in box. Heck I can't even get an Edelbrock EFI truck intake for the 5.8 in a timely manner. They just keep extending the ship date i had to cancel and modded a 302 intake to fit. Will take it to my local tuner if all else fails.
. I have the HEI distributor, new in box. Heck I can't even get an Edelbrock EFI truck intake for the 5.8 in a timely manner. They just keep extending the ship date i had to cancel and modded a 302 intake to fit. Will take it to my local tuner if all else fails.
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So the tuner said he had to adjust the injectors to 24lbs in order for it to run proper, but my injecots are 30lbs. Decided to test the fuel pressure and it looks like the rear tank is around 15 psi at idle, front is 25 psi, no wonder the rear kept getting a lean condition. I know the pressures aren't good and it drives fine with the front, with no lean condition, it's only the rear that seems to have the issue. Will measure pressure at the pump tomorrow am. These are 2 new pumps btw, from quantum fuel. it does hold pressure with key off. Just not 30 to 45 psi.
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