I picked up on something kind of odd on my way home today from work...

It would seem (by butt-dyno) that the truck "pulls" harder at 1/4 throttle than it does at full throttle

If I DO go to full throttle for a bit, like in 3rd or 4rth gear, and as it's still accelerating, back off to about 1/4 throttle, I seem to get a little "boost" in acceleration, and then if I go back to full throttle, it looses that "boost"...


It's not sputtering or anything; heck the truck's running great actually! The fuel milage is good, and I don't smell anything odd in the exhaust, but there is a little black residue built up on the inside of the exhaust tip (which got there quick; this is a NEW exhaust tip; it's been on there a week), but the truck doesn't smoke at all.



I have one guess; the stock intake piping and filter assembly is too restrictive after the engine mods during the rebuild. The motor is bored .30 over, has engnbldr's street/RV head with the oversized valves and the 261 cam, and has header and cat-back kit. But I'm still running the stock intake tubing and filter box, with just a K&N filter. Maybe I'm starving the truck of air, which is causing a "more fuel than air" situation and leading to the black buildup in the exhaust?



Any input would be appreciated!


Thanks!

 

TPS adjustment, AFM maybe... leak in the intake. Timing...?

 

TPS is right where it needs to be, last time I checked (during the rebuild, and it hasn't been touched since), but I could check again

AFM is relitively new; my old one was all but destroyed after ingesting some water, lol

I'm fairly certain the intake itslef isn't leaking, but I haven't thoroughly searched it yet, but that's an easy inspection

And the timing I checked again after the last valve adjustment about 3k miles ago, but I could jump the terminals and throw the timing light on it again, just to be sure




Thanks abe!

 

Well it has to be a fuel to air mixture. It seems like it might not be getting enough fuel? Maybe an o2 sensor?
My o2 sensor gives me hesitation, but nothing like you have. I would put my money on lack of fuel, or bad afm. (although im no mechanic)

 

it sounds like the timing isn't advancing correctly. the stock intake shouldn't be causing a rich mixture. did you adjust the AFM? might help.

 

well i find any throttle passed 1/4 doesnt make a difference with my 22re lol really i only use 1/4. seems like the harder i push, nothing happens lol. maybe its because i have 116 hp?

 

Too much air so clock the afm rich?

 

i say advance the timing a bit to make for the bigger exhaust/bored over.

 

right, but I was under the assumption that 116hp would be a peak at full throttle at a certain RPM, not just OH, 1/4 THROTTLE, THERE'S ALL THE HP!!! if you catch my drift, lol




The O2 sensor was replaced about 5k ago, shortly after the rebuild


The timing is going to advance according to readings from the TPS and AFM, correct me if I'm wrong there. As far as adjusting the AFM, as I touched on in another thread in debate right now, from what I gather, it's kind of useless, but I guess maybe, stiffening up the spring a little to make up for the excess flow, might help things a bit?




Thanks for all the suggestions guys!

 

Is your Throttle cable adjusted to where butterfly is 100% open at 100% throttle?

 

My 3.4 in my 4runner has more pull at about 3/4 throttle than wide open.
I've noticed this about alot of other cars too, except for when driving autos.
My girlfriends 22re gets more pull on the freeway when it's not wide open vs being wide open. Like you can go up a hill and kinda feather the gas pedal between wide open and 3/4 and feel ur self gain more speed vs holding it down. I always thought this was weird.

 

I know you said you've checked the TPS, but have you checked for dead/worn out spots? Use a multimeter with the bar that goes up as resistance increases. If that bar blinks at all, you've got a dead spot.

 

I hope it doesn't have dead spots, it's not that old! I put a brand new one on it about 4 or 5 months before the rebuild!


Lol, but yeah I'll check it out, thanks!


I think next time I go to a junk yard, I'm going to snip off the wire harness plug for a TPS, so that I can plug it into the TPS on the truck, and just tap right into the wires in the cut-off harness... that would be SOOOO much easier... I might have to stop by the junk yard on my way home tomorrow now, lol

 

Been doing it this way for six years w/ my Supra, and 4 years w/ my Pickup. Much easier for sure.

 

dont know about you but my truck seems to make most power at half throttle. the more i press the gas the longer it winds out, but pretty much stops MAKING power after half throttle. if that makes any sense. kind of hypocritical of me tho considering my foot is always on the floor

 

fwiw, i'm advanced 12* right now running 91 octane and am having no problems. truck is running really well and holds good power at 6k

 

Ya know I kinda feel like my does it too after 1/2 throttle it still gains rpm but don't pull hard like before 1/2 throttle and I am at 8 degrees advance on 89 octane no real issues runs 90 mph no problem until a hill shows up lol

 

i dont know what to do with my 22re. it runs good, gets crap millage for a 22re, idles super high when cold, 1/4 throttle is about all i use, cant see any visible vacume leaks, my maf looks nice and clean and the flappy thing inside works? i basically have given up and just drive it lol

 

maybe, just maybe, its in your head. kinda like going from a straight pipe to a good muffled exhaust. it makes allot less noise and makes same power but feels more powerful.

 

Check your cat(clogged) and 02 for crappy mpg