95.5-2004 Tacomas & 96-2002 4Runners 4th gen pickups and 3rd gen 4Runners

Engine TOO LEAN! help!

Old Sep 23, 2008 | 10:24 AM
  #1  
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Engine TOO LEAN! help!

Ok so i bought this gorgeous 4runner about 2 months ago and it threw a CEL about two weeks ago, diagnosed it and it said the engine is too lean. Now ive read about these supercharged engines and they have problems with this.

Would getting the urd 7th injector kit fix this problem? I am a college student with barley any money to spend so its kind of out of the question.

Im just curious to see if i can just buy a walbro fuel pump or something to fix the problem. Any Suggestions???

Thanks,
Andrew
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Old Sep 23, 2008 | 10:31 AM
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It would be best if you post the actual CEL code you got but basicly if its running too lean you have 2 general options, more fuel or less air. The cheapest way to go would be less air and Toyota even came out with a bigger than stock SCer pulley that limits boost to 5psi IIRC. You could also screw your deck plate in, may help a little.
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Old Sep 23, 2008 | 10:44 AM
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Yeah. The deck plate mod sure doesn't help and is not needed with the s/c. Cap it off. You'll probably need the fuel mods like everyone else has that's s/charged. Buying just the Walbro pump won't really help if you don't have the larger injectors to deliver the increased fuel and a controller (piggy-back computer) to control it. Post the code your getting
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Old Sep 23, 2008 | 10:48 AM
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Okay, deckplate was capped once the light came on so ill get the actual code and post it up
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Old Sep 23, 2008 | 10:49 AM
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I'm guessing you got a P0171, I have gotten that code sometimes when doing a lot of idling at high elevations or rapid elevation changes. I have a A/F gauge, complete URD fuel mods and know that I'm not running too lean during high boost so I suspect (in my case) it is a ECU adjustment issue at low rpms. It only happens to me in the mountains.
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Old Sep 23, 2008 | 10:55 AM
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Another thing that sometimes helps is to check the sensors that help the ECU adjust the A/F ratio, namely the MAF and front O2 (A/F) sensor.
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Old Sep 23, 2008 | 11:46 AM
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Mine read too lean as well...it was the MAF sensor.
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Old Sep 23, 2008 | 04:57 PM
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I cleaned the MAF its in good shape, code still comes up and it is a P0171. I am going to check the O2 sensors tonight and will get let ya know.

Also, I am in the foothills of denver and this car is from ohio, so quite an elevation change. Is there any way to tune the stock ECU?

Last edited by andrewd; Sep 23, 2008 at 04:59 PM.
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Old Sep 23, 2008 | 05:11 PM
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Originally Posted by andrewd
I cleaned the MAF its in good shape, code still comes up and it is a P0171. I am going to check the O2 sensors tonight and will get let ya know.

Also, I am in the foothills of denver and this car is from ohio, so quite an elevation change. Is there any way to tune the stock ECU?
You can re-set the ECU memory by pulling the battery cable for about 15 minutes, that sometimes will help it adjust to elevation changes faster.

The URD kit has a way to tune the A/F ratio.
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Old Sep 25, 2008 | 08:15 AM
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Okay, Checked the O2 sensors they look good, so I re-cleaned MAF, and tightened all of the fittings on the intake, one I found was a tiny bit loose. Pulled the battery cable and as far as I know the code is gone. Thanks for the help guys!

-Drew
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Old Sep 25, 2008 | 09:35 AM
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FYI:

To clear a code, instead of pulling a battery cable, just pull the fuse from under the hood for a few seconds. This way you don't have to reset your stereo, clock etc. It accomplishes the same result
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Old Sep 25, 2008 | 11:17 AM
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Originally Posted by andrewd
Okay, Checked the O2 sensors they look good, so I re-cleaned MAF, and tightened all of the fittings on the intake, one I found was a tiny bit loose. Pulled the battery cable and as far as I know the code is gone. Thanks for the help guys!

-Drew

I cleaned my MAF too and reset to battery....it lasted a few days and came back. I replaced the MAF and its been good ever since plus I gained 1-1.5 mpg on hand calculations.

If the CEL comes back, I would bet its the MAF.....
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