lol 18 gallon tank ! so about 16 to 20 mpg i average 18.7 over the last couple mths

 

after reading all of this i decided to give it a shot. i got an AFM from the local pull-a-part.

how do you like my amazing tape job? o and how the hell do you mount this thing? because the wholes would line up but ther all atleast a quarter inch to high... pics of this on a stock airbox would be sweet!

 

with a lil help the bolts do go into the holes and all that tape then can be used for ?????? anything else

 

FWIW, this mod will make your truck run leaner.

I have done this mod, and lost around 2mpg because of it. No difference in driving style, just the mod with 3 clicks on the AFM. I did notice a slight increase in low end throttle response, but IMO its really not worth it considering you could get the same throttle response from simply moving your stock AFM three clicks.

Honestly, this mod really does nothing except lean the mixture more making you "feel" like you get more power. When, in reality, you are reducing the life of your motor with the leaner mixture. And, for the record, it did throw a check engine light with a 25/26 code from time to time. I could reset the codes, but after 150miles or so it would always come back. So, I just switched back to the stock AFM and haven't had a code thrown since.

On a side note, I just replaced plugs tonight and they definitely show a lean burn on the them. Prior to that, I never had issues with the plugs showing that.

So, there is my opinion on it. It doesn't do squat except lean out the burn.

 

any way to adjust the timing to compensate for that?
and i wonder how this would work for someone with cams/bigger valves/valve jobs/throttlebody/full exhaust... to my knowledge, no one with a heavily modded 3.0 has done this... i mean, it may be the key to fixing the 3.0...

 

o... well i feel like a dumbass. haha well it looks like a turbo or a chevy 350 is the real answer...

 

Guys, what makes you think this "leans" out your mixture and more, why would you think that would increase power? You need to burn fuel to get power. Richer (up to a point) will decrease the likelyhood of detonation which will allow the engine to advance the timing farther. Leaning increases combustion temps and predetonation which the knock sensor detects and retards the timing. Your O2 sensor is monitoring exhaust to try to maintain the proper mixture at all times.

You might play some tricks with the computer's maps feeding it signals biased one way or the other (clicks on the AFM adjustment) but you are not getting more power and better throttle response from "leaning" out your engine.

Just ask anyone who has experimented with rejetting and tuning a motorcycle about lean spots. Bike falls on its face.

Letting the engine breath better will improve high end torque (power) because these restrictions become issues during high flowrate operation. For slow torque demand where air flow is slow it really doesn't matter if you have a large or small orifice in which to inhale air. Those partial throttle settings are the operational zone where the engine is running closed loop and is most efficient and is where one operates it to get the best fuel economy.

Frank

 

and all of that means what exactly??? so what should i do?

 

Well, if you like how the engine performs, maybe make a more permanent long lasting intake solution without duct tape.

If it opens up the mid range and high end cool. If you drive up there all the time because of it, well you might see less MPG. But, if you can climb hills / accelerate with less pedal and your transmission doesn't downshift as aggressively/upshifts sooner (applies to autos), you might see an increase in MPG. Tough to say but it seems most people here are seeing what one would expect them to see which is an improvement in performance with little change in MPG.

I was mostly just addressing what seems to be an confusion between spark engines and diesel engines. Diesels get more efficient when you add air (lean out) because of their unique thermo dynamic cycle although the need fuel, lots of it, to produce more power. Spark engines on the other hand cannot run lean like a diesel because it burns hotter causing gasoline to self detonate (predetonation or knock). So, you increase air, cool but the engine is just going to increase fuel to match it because it has to and that is what it is programmed to do.

Frank

 

The point is with this mod, that the new AFM adds more air (leaning the mixture), and therefore the computer then must add more gas to compensate. Too lean, and the computer cannot adjust that much and you will begin to ping(predetonate), and thus will begin to burn your cylinder walls. This will lead to earlier engine failure, higher engine and exhaust temps, and a quicker reason for a 3.4L swap.

 

Actually, it will just retard the timing like crazy if it gets that close to pinging.

Remember, at mid RPM's(where knock occurs) your engine at WOT is pulling much less air than it can at high RPM, WOT so your injectors will keep up.

Frank

 

well i already get rediculously horrible gas mileage so any sort of performance help is nice even if it doesnt help gas mileage. besides ill probably be doing a chevy 350 swap soon anyway

 

Sure hope you like body lifts and rear mounted radiators then...........

 

The computer can only do so much. It will still ping, if too lean. It will also throw a engine code because it can't adjust enough.

 

by the way i am on 37"s with IFS... i already have a body lift. and i already have had to replace my radiator mount because there was a TPI 350 in it before it was given to me...

 

It would probably help if the AFM was adjusted a few notches richer to compensate for the extra air flow.

 

yeah probably so...

 

I have a 90 auto with 31s but geared for 28" (4.10) and have the heads ported and polished, cams reground, ISR and air filter mod as well as a full 2.5" exhaust from the manifold back with hi flow cat. Performance increased quite a bit especially after the exhaust mod (which was done about 3 months after the head and cam work).

Somebody send me one of those AFMs and I will test it on my rig. I get 220 to 240 miles to 15 gallons of gas per week. I have ran 30" tires and currently run 31s but still get 220 miles per 15 gallons. (performance drop with the 31s) How about it? Im ready to test.

 

bringing this back from the dead...

i've read accross similar threads on this mod and it is incredible that there's no clear consensus on whether this mod leans the mixture or not. can anyone definitively say one way or the other whether it causes the engine to run lean? i suspect it doesn't but have no way of proving it.

(mind you, it's more incredible that nobody has put a 3vze on a dyno but that's another story altogether)

 

Well, think of it this way.
With the larger AFM, you're increasing airflow.
But, since the AFM came off a smaller engine, it's safe to assume that the amount of fuel/air mixture was run slightly leaner than it would be on the 3.0.

So, by putting this AFM on the 3.0 you're running it at the settings it would be at on the smaller engine. It's most likely going to be leaner, but that's just my .02.