ISR + Deck plate = P0171 ?

tyr0981

tyr0981

New member
So i completed the Deck plate mod at the begging of this summer (and i love the improved throttle response!) I noticed an increase in the frequency of my P0171 engine codes, every month or so.... so then i ditched the PIA K&N filter, for an oil-less Air Aid, thinking i somehow had more oil being pulled off the filter.... didn't fix anything.

So this weekend I figured why not finish up the intake with an ISR mod (even better throttle response and i swear a little more power + the noise is epic!! :tongue: ) however, every time i take her for any drive i get e CEL with the P0171 code, every time. I've cleaned that MAF sensor so much it is cleaner then my eating utensils! used MAF cleaner + tissue paper, then blew off (gently) to remove any residule lint that sucker is in predestine shape! i even cleaned the entire air box and pipe for good measure. Still every time she starts up, within a few minutes i've got a Pending code (ultra-gauge), then in~5 min or so a CEL P0171 only, no other codes.

Basically, is my MAF sensor broken?

A new Toyota sensor is 134$ from CamelBack.... I just want to know if anyone else has had this happen to them and or thinks before i replace the sensor.

Thanks in advance for your help again guys!
 
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The deckplate/isr is throwing off your cross-lateral inversion matrix, resulting in the code. If you add a t4r sticker and some TRD decals in the back it should clear it right up, and get you another 15hp or so.

:p

Just messin with ya. I got no idea here.
 
I just dealt with this as well. I have the deckplate and duct tape ISR mods and had the P0171 pop up. My mistake was that I didn't have the vacuum hose that connects to the intake pipe, connected. Dumb mistake. Mine eventually went away though. No clue if that was the complete issue or if that was just the one thing I noticed. Sorry that this doesn't help. Maybe recheck your vacuum lines? Lol.
 
Jaketino said:
I just dealt with this as well. I have the deckplate and duct tape ISR mods and had the P0171 pop up. My mistake was that I didn't have the vacuum hose that connects to the intake pipe, connected. Dumb mistake. Mine eventually went away though. No clue if that was the complete issue or if that was just the one thing I noticed. Sorry that this doesn't help. Maybe recheck your vacuum lines? Lol.
Click to expand...

the hose that plugs into the air-box is in ruff shape, i just ran it up the nipple past the split end, and put a hose clamp on it:

ebf79cb2-d8cf-42ba-855c-c932c607b63d_zps5a938ea9.jpg~original


i followed a write up that replaces the vacuum line off the silencer box, with this one here:

T_zps6d82575e.jpg~original


Maybe it is my AFM has worn out? it's had these problems with the P0171 since the day i bought her, i clean it and it goes away for a time.... 258k miles...
 
I did the deckplate. Wheeling in dusty conditions the other day, put the plug in...within a few miles, got a cel..... pulled the plug back out, disconnected the batt, cleared code and hasnt come back... I also pulled the relay to reset it...forget what its called.
My theory is that it reads the air flow without the plug in, since I reset that relay, and the plug changes it enough to throw a code. Did you try unplugging the relay? Seems like it has to get used to the new condition.....but I am just guessing here.
 
riflecountry said:
I did the deckplate. Wheeling in dusty conditions the other day, put the plug in...within a few miles, got a cel..... pulled the plug back out, disconnected the batt, cleared code and hasnt come back... I also pulled the relay to reset it...forget what its called.
My theory is that it reads the air flow without the plug in, since I reset that relay, and the plug changes it enough to throw a code. Did you try unplugging the relay? Seems like it has to get used to the new condition.....but I am just guessing here.
Click to expand...

I cleared the code with my 'Ultra-Gauge', the link you gave for cleaning process is exactly what I've done, except for the EFI un-plug / re-plug since i have the on board diagnostics system.
 
So i'm going to go out on a limb and guess nobody has had a MAF failure? i'm leaning that way but don't know what the indications are.... i think if my engine really was running lean on the left bank, there'd be some other codes being thrown also....?
 
tyr0981 said:
So i'm going to go out on a limb and guess nobody has had a MAF failure? i'm leaning that way but don't know what the indications are.... i think if my engine really was running lean on the left bank, there'd be some other codes being thrown also....?
Click to expand...

I am pretty sure I have a spare MAF laying around. If you can wait a week, I'll be passing through Longview next Friday afternoon on my way home. If you cannot, I can see about dropping it in the mail tomorrow.

I'll shoot you a PM
 
A "spare MAF" so you've been through something like this ? i don't want to take your spare parts from you, i really appreciate the offer, i just don't want to start throwing parts at a problem i'm not sure about... you know....

Did your meter crap out on you? did it go in a similar fashion as mine?
 
tyr0981 said:
A "spare MAF" so you've been through something like this ? i don't want to take your spare parts from you, i really appreciate the offer, i just don't want to start throwing parts at a problem i'm not sure about... you know....

Did your meter crap out on you? did it go in a similar fashion as mine?
Click to expand...

Sent you a PM, but for the good of the group my issue was that I installed my gasket on my 7th injector incorrectly. So a vacuum leak.

Check, double, and triple check your lines.
 
I'm going to take Wilson's advice, and go hunting for vacuum leaks... not sure where to start, but will begin with the two pipes i messed with, and then onto the throttle body. Then a smoke test with a cigar if push comes to shove, not sure i want to shove a vacuum line in my mouth, but if push comes to shove!

:tape:
 
I would say a vacuum leak. Your lines look pretty rough. I would buy an assortment of vacuum lines and replace them all. That's what I did and it looks a lot better too.
 
HOORAY!!!! the vacuum line to the 'Throttle opener' (at least that's what the interweb calls it) was unplugged here:

Unplugged_zps0c16666b.jpg~original


I drove around the block and no code's.... I can't thank you all enough for the the help!

like Wilson said! check, re-check, tipple check! and if i may add one, lightly tug on the lines to see if it's just resting against the plug! :ybrick:
 
So i was poking around my vacuum system today (planning on cleaning up my birds nest of battery cables) and i noticed this do-hicky:

4wdsolenoid.jpg~original


appears to be smashed and missing the back portion, and the front portion to be horribly mangled..... it's called a VSV for the 4wd system (from what i can find in pictures on the forum) i don't have any issues getting her into / out of 4wd, but have received the P171 code again a few times over the past week, so i know i do have another vac leak.... somewhere..... should i consider this a possible source of the leak since it's so mangled, even though i don't have troubles with the 4wd?

thanks for the advice guys!
 
here's the mystery part:

Overview
location_zps8b0e9d18.jpg~original


Close up
Part_zpsb182d1d7.jpg~original


Any input is appreciated... thanks again!
 
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