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-   -   lean at wot, but only in closed loop (https://mustangforums.com/forum/5-0l-1979-1995-mustang/558520-lean-at-wot-but-only-in-closed-loop.html)

ctgreddy 08-24-2009 07:51 PM

lean at wot, but only in closed loop
 
Ok I finally played around with my car. and Noticed that at wot my afr is around 13.0 when its not yet up to operating temp, so in open loop. And after it gets up to temp or has been running a couple minutes it leans wayyyyy out at wot, around 16-17. It didn't do this with the last motor, and at idle/cruise the afr's are the same wether in open or closed loop. So what could be up? I plan on getting this retuned but can't get it done for another month as the shops booked up. Could something be bad causing this to happen? Obviously I will not be beating on this car at all until I can atleast fix this issue, but if its something like a sensor i'd like to get it taken care of before I take the car in to get tuned. so any ideas?

mjr46 08-24-2009 10:26 PM

add a little more fuel pressure and see what happens

ctgreddy 08-25-2009 05:28 AM


Originally Posted by mjr46 (Post 6444789)
add a little more fuel pressure and see what happens

it richens out everything but I upped the pressure from 40, where i'm at now, to 55, and it was still lean at wot, it was in the high 14's then at wot but would stall from being too rich.

Joel5.0 08-25-2009 07:51 AM

Run the self tests to make sure the EEC is not working with a failure code condition, but looks like the fuel_table_xxxx tables need some work. Have you checked the AFR with the O2's disconnected (forced open loop condition)? LUK

ctgreddy 08-25-2009 02:53 PM


Originally Posted by Joel5.0 (Post 6445462)
Run the self tests to make sure the EEC is not working with a failure code condition, but looks like the fuel_table_xxxx tables need some work. Have you checked the AFR with the O2's disconnected (forced open loop condition)? LUK

No I haven't checked that, I'll run a self test tomorrow and try the o2 disconnect, what are some codes that I would get if it were working with a failure?

AdderMk2 08-25-2009 04:04 PM

what maf/injector combo are you running? have you pulled and inspected the plugs?

its possible that your MAF is pegging out, or you could have a bad injector not firing fuel, causing your car to pump air into the exhaust, simulating a really bad lean condition

ctgreddy 08-25-2009 07:02 PM


Originally Posted by AdderMk2 (Post 6446421)
what maf/injector combo are you running? have you pulled and inspected the plugs?

its possible that your MAF is pegging out, or you could have a bad injector not firing fuel, causing your car to pump air into the exhaust, simulating a really bad lean condition

its a pro-m maf with frpp 30#'s. I've pulled the plugs and they look alright I guess, not white but not perfect either, they all look the same tho.

I guess it could be my maf, could I try throwing my stocker in? wouldn't that just make it run super rich? however if it were a fuel injector not firing wouldn't it be doing it all the time not just closed loop?

AdderMk2 08-25-2009 07:14 PM


Originally Posted by ctgreddy (Post 6446870)
its a pro-m maf with frpp 30#'s. I've pulled the plugs and they look alright I guess, not white but not perfect either, they all look the same tho.

I guess it could be my maf, could I try throwing my stocker in? wouldn't that just make it run super rich? however if it were a fuel injector not firing wouldn't it be doing it all the time not just closed loop?

i was just throwing some ideas out there...
do you have any bends in your CAI before the MAF?

i wouldnt run the stocker, its too bad you didnt live closer... i'd stick my quarterhorse on your car and see wtf it was doing

ctgreddy 08-25-2009 07:19 PM

yeah it sure would be nice to figure out whats going on. I'd hate to have to park the thing until I get it retuned. The sucky part is that I have to pay another 625 for a tune, I was hoping for a discount since its already been tuned but no such luck. Nobody go to livernois. And If i get to the tuner and find out I have a **** maf my cars going to be done until next spring. Hopefully running for codes will tell me something.

5.0stanger 08-25-2009 08:07 PM

I am currious too about your CAI. I know if it has bends in it like Adders asked, you might have to clock the MAF. I know on my carI have to keep it turned a little so I don't look like I am crying while driving the fumes are so bad, LOL. If I turn it, it gets better.


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