david braun

Had my 3.4 apart today at least 5 times checking for vac leaks and anything that could cause this problem, plugged all 5 vac holes on the intake so its not the problem.
rubber intake between the maf and throttle body also is air tight as well.
New or in spec
maf reads 80+ engine load at WOT and correct gps.
Just bought a denso upstream o2 today no fix
tps new
coolant temp sensor new
injectors just cleaned flowed great

It runs really nice besides the lean/rich condition and really bad gas mileage
Idles at 725-760
When i tap the gas peddle ltft goes from +19.53 to -20.25 with nothing between just those numbers, causing a slight pop in the intake, short term goes up as it should but always ends up -20.31.
The voltage during this time is a flat line at .94 at idle and i know it should be a wave length.


98 tacoma engine
auto ecu, 5spd swap 3 codes po130 po133 and (po1700 this in normal till i get a 5spd ecu)

Fixed!!!

david braun

Could the IAC valve gasket cause a vacuum leak? noticed mine was kinda squished and may not be making a seal will be ordering a new one of those.

FPR seems to be okay, no leaking out of the vac hose and the fuel pump is also new.
Will be checking for a crimped fuel line in the PM.

For some reason of which i don't understand its running lean +19ltft but short term is correcting it with a rich 20- and also the .91v but i have no idea where i could be getting a vac leak!
i also have no lean codes.

vital22re

iTrader: (2)

the p0130 and p0133 go hand in hand. You need to verify the wiring to the primary 02 isn't damaged. And you need to make sure you have no exhuast leaks above that o2.

david braun

Already checked the wiring several times, is there a way to check the voltage coming from the ecu?

Just checked timing belt and the bearing has been making some grinding noise never knew where it came from.
Cams line up pretty close but the crank pulley is off almost 5 degrees took some pics.
Also if you look down inside the lower cover there was rubber marks on the pulley like skid marks? no pics of that dunno why lol
would this cause it to run lean?
Coolant MAY have gotten on the belt at one point or another.....

david braun

vital22re

iTrader: (2)

looks like your crank timing/phasing could be slightly off, maybe a tooth or two

david braun

Yep this was the last straw for me, already ordered a timing belt kit OEM no aftermarket cr@p for this 4runner!
Lots of walkthroughs out there for the timing belt replacement, how long would ya think it takes for a first timer? I plan on fully removing the AC unit and tossing! No need for it in Oregon! also bought the special tensioner tool just because.

vasinvictor

iTrader: (3)

Go ahead and carve out a weekend to do it. Don't be in a hurry. After you do it the first time, you can probably get it done in 5 hours or less.

david braun

Well i finished the T belt and removed all the A/C crap while i was at it and was surprised with how easy it really was (took the grill out and rad made it much easier)
The tensioner bearing was shot, had belt marks where it had frozen up due to pitted bearings so i am glad i replaced that, runs much better but i still have the lean condition (T belt kit fixed the jumped timing)

No vac leaks at the 5 vac ports checked with carb cleaner, also ruled out the brake booster.

When at idle (650-700) fuel trims are way off (long term +19.4 short term -20.5, idle up to 1200 and short term comes right down and fluctuates like it should long term goes -20 also long term is always a flat line with the changes.

During this time the o2 sensor voltage is at .94 at idle (650-700) no wave length till idled up then its normal wave length.

I pulled the (air assisted) hose off the IAC valve while it was running and there was strong vacuum at the hose, not the IAC side. I don't remember that last i checked, any input?



I'll try and get some screen shots from my reader next time i have the chance.
Forgot to add that i DID reuse the metal gaskets for the intake plenum and have ordered new as of tonight just in case its leaking there.

vital22re

iTrader: (2)

reset the ecu and watch trims again.

david braun

Just replaced the intake mani gaskets the top 2 only never needed the lower injector mani gasket.

Still the same fuel trims, i created a vac leak at the brake booster and my fuel trims came way down and the voltage started moving around it was a little off but long term came down to 3.3 also reset the ecu this time also runs much better besides a slight lope no more pops out the intake when given gas.
i'm guessing this is a fuel problem? thought the fuel pressure regulators rarely go bad... new fuel pump also idk also a vac leak anywhere else on the top plenum would kill it.
Anything other then the regulator that would control the fuel pressure?
almost seem like its the injectors...
When took them out and the driver side far back injector looked a little melted but when i hooked it up to a battery and injector cleaner it didn't leak and did really well, it was under pressure also.

david braun

Ended up running the fpr vacuum line to the vac port for the starting solenoid (by the TPS) upped the idle to 1000 with an idle screw and fuel trims are looking normal.
Short term is still +3 - +7 i know thats not where they belong so ill be reading the spark plugs to see if one of the injectors are leaking mpg are a little better i think not positive.

david braun

Fixed!
Pulled the complete engine harness out of the engine and cut a ton of the old auto ecu wires out just because harness is already hashed due to the douche who got cut happy when swapping it.
cleaned up all the connections seemed like some of the wires including the o2 sensor wires where slightly melted no wire showing but close.
I'm back to 18mpg hwy and fuel trims are normal!