01 F-150 XLT 4x4, 5.4 Procharged 9# boost, 42# inj., 90mm MAF, 3'' Flowmaster exhaust. I'm on the 2nd SCT tune download and my A/F is still at 15, too lean. It still has the stock in tank fuel pump along with the in line ATI pump. Do I really need to go to a 255 cfm pump? I'm also having some belt slippage around 4300 rpm. Any ideas out there?

 

Are you @ 15:1 during the whole pull? Or just uptop?...If your lean up top,then try a new fuel filter,if that dosent help youll need the larger intank pump and remove the noisy inline one from ati.That or its just the tune
As far as belt slip,I adjust my tensioner until the springs are fully compressed,and use the shortest non-gatorback belt I can fit on w/the tensioner outa the way.
In addition to that I also added another pulley on the bracket to get more belt wrap.



Good Luck!
Frank

 

I had a lean WOT situation with my ATI also on my ī05 FX4. It turned out to be only a matter of custom tuning and at the dyno everything was solved. Look into this before you start buying extra equipment. The A/F ratio should be in the neighborhood of 12.5 - 13.0 at WOT. If you have the diablo predator programmer, give diablo sport a call, they should be able to assist you. Good luckĄĄĄ

 

The AFR's were at 15.2 at cruise. At around 3200 rpm it drops to 10 and then levels out around 12 until the belt starts to slip. The guys at Pro Dyno in Tempe recomended adding another pulley to get more belt rap and maybe a larger in tank fuel pump.

 

Noooo, wide open AFR should be 11.8-12.0 to be safe, 13.0 is way too lean at wide open if you want your engine to live. At cruse it should be around 14 I believe.

 

I know you're right, but I guess this is a slow process. They're making small adjustments to the tune as we move along. After the first tune, I picked up about 25 hp. At this point I'm at 275 rwhp & 337 rwtq. I really hope to see 300 rwhp by the time we're done.

 

Even with a ballpark (non-dyno) tune from Mark Lancaster I was making well over 300 rwhp..around 330 actually. You don't need a fuel pump, just someone who knows how to tune. I'd send your A/F logs and chip to Mark as I'm sure he could get you a lot more power with no lean spots. As far as belt slippage...yeah that's just something you'll have to work on. I'd like to use those pullies like Frank has, Daycos, but I have no way of making spacers. Definately need the tightest belt you can get on without the tesioner though like already mentioned. It should be a PIA to get the belt on and you'll have to loosen a few of the idlers and exercise some arm muscles but that's the way it's supposed to be. I had bad belt slip when I went to a 12# pulley and mainly because I had the wrong size belt, loosing 3 psi after 4600 rpms.

 

330 rwhp is great but do you have a 4x4, & an auto transmission? The boys at Pro Dyno estimate a 30% loss through the drive train.

 

Flavio,
Glad to hear you got things worked out...what kind of numbers did you put down??

 

This has been discussed elsewhere, without resolution. The 4r70w eats 65 hp or so, and some say you would lose a nother 10 hp for the 4wd. If you say 30% loss, that's a 99 hp loss at 330.... I don't believe it.

I am running nearly the same set up with a Powerdyne and only a 190 lph in the tank. My column mounted a/f gauge tells me that I am too rich, as low as 9.6, at anything more than about 1/4 throttle, with my first baseline tune.
I think you may have enough fuel available, need a better tune/tuner.
g luck

 

I thought 30% was a little high myself but what do I know. There does seem to be no difinative answer to that ? just speculation. Doesn't really matter anyway. RWHP & RWTQ is more important to me, it's just nice to say the higher #'s when asked. I've heard that the ATI in line pump may also cause some restriction rather than add more fuel pressure. If there's anyone out there that knows about that, please let me know. So now I'm waiting on another tune then we'll see where that goes. Thx, for your info.

 

i dont know about percentages...i put down 333 rwhp/ 404 lbs tq....with the 4r75 and 4x4...i didnt realize that the 4x4 contributed to a little greater loss until now, so that makes me feel a little better...

 

you have plenty of fuel with the 42's and the inline pump. your a/f ratios arent bad. the 15 is ok for cruising. it should be around 14.7 (stoich) if its perfect.

try a different tuner. prefereably someone who has tuned prochargers on
f150's. you should be making a lot more power than that.

 

Hey man, after I dyno tuned, I got 330 RWHP. I didnīt want to up the rev limiter just to keep the valve train on the safe side. At 5200 rpm power was still building. I couldnīt be happier with the truck now. I now have the truck leveled ( with the 20 " rims it looks awsome). Next step will be e-fans and exhaust. Just out of curiosity, whatīs the stock hp at the rear wheels?? I think I gained 100 hp with the procharger. Luckily, it was just a matter of tuning.

 

I bought the SCT Excal 2 from Power Surge Perf. in NY and they're doing the tune. they do work alot with Fords and Prochargers so I'm going to work with them a little more. As far as the A/Fs I was under the truck today on unrelated matters when I noticed that the fuel in line to the in-line pump has a minor pinch in it. Not enough to completely shut down the flow but I think it might be enough to slow it down a little. As soon as I can I will relocate the pump to get rid of the pinch.