Clean 3.4 V6, Just SC'd. Now what?

[SliderNH]

Hi All, Just installed my SC, runs good and powerful, but now I got a CEL. Spent 2 weeks chasing a P0171 (Lean code) so far. Looking for further suggestions. I've supplied as much information and back-story as possible. If theres anything I'm missing, Let me know, if you have ideas, let me know, if you want to just say how sweet SC'd 3.4's are, Let me know!!

Heres my set-up: a well documented, and very clean history 2000 4runner, 110K mi automatic, 3.4 V6 CA emissions, with 2nd gen SC, stock air filter, stock headers, stock exhaust. (Everything is stock except for the SC + FMU mod). Other non-related mods are the Sonoran 1.2 lift, B&M transmission cooler, Tundra brakes, and Skip's gas tank skid. Its sitting on 265/75/16 A/T's. The vehicle is located and driven in Corpus Christi TX (18' MSL). I did the nosecone rebuild, SC install, replaced the timing belt and tensioner, water pump and temp sensor, and valve cover gaskets in one shot (Note: All parts used are OEM Toyota, from the dealership). Before the install I purchased your 7th injector kit, pug-and-play wiring harness and the 2.2 pulley as well. The weekend of the project, I was able to install everything except the 190LPH fuel pump, plug/play-harness, and the URD Performance Calibration Unit. There wasn't time to do the fuel pump. As for the wiring harness, and the PCU, I attempted the install but the truck would not run with the unit. It would turn-over, and sounded like the engine would fire for .75 - 1.25 seconds, but nothing more, even with the throttle engaged. I removed the PCU, same thing. Then I removed the harness also, the truck started right up. Test drive: smooth, powerful, SC whine, and rattle at idle. Only problem is CEL came on after first 12 miles.

I ran the truck like that for a week (its a daily driver). That is: New timing belt/tensioner, power steering belt, SC belt, Water pump, temp sensor, new valve cover gaskets, Rebuilt nose cone, 2nd gen SC, 7th Injector, Injector harness (not connected electronically), supplied vacuum lines, Two-step Denso Iridium Spark plugs, 2.2 pulley. I got the CEL code scanned at the Toyota dealership, Lean Code P0171.
Thats when I called Gadget the first time to tell him about the issue with the truck not being able to start with the PCU installed. I sent the PCU and harness back to him for further diagnosis. Gadget also informed me that the Lean code needed to be fixed which could be a result of a Vacuum leak or bad MAF sensor, and needed to be fixed prior to installing the PCU and harness.
I did not believe the MAF was bad because it was fine (no CEL) before the SC install. However, the first thing I did was clean it, and reset the ECU. After the MAF cleaning, I let the truck idle for 25 mins (long enough for a CEL to be thrown if there was a vacuum leak). No CEL until the next day when I drove it. Same situation, roughly 12 miles into the drive CEL came on.
This past weekend, (March10/11: 2 weeks after initial installation) I tried again. I installed hose clamps on all of the vacuum lines just incase there was a vacuum leak i didn't notice, the 190LPH fuel pump supplied by URD, and new OEM Toyota fuel filter. I reset the ECU, and drove the vehicle gently. CEL came on at 25 mi.

So, that leads us to where I am now. I have been doing research on customtacos, yotatech, and the 4runner forum. I have turned up other possibilities for the CEL P0171. O2 sensors, and MAF. I have read other 4runner owners who have experienced the code are able to fix the problem by replacing the above mentioned parts. The important thing to note is that most of these individuals did not experience the CEL P0171 directly as a result of the SC, rather; they had an ongoing issue that they were able to fix by replacing these parts.

I am looking for further suggestions so I can fix the issue. My goal is to have a reliable SC'd 3.4 that will not throw codes, melt pistons, or blow my engine. I would like to monitor the engines performance, with AFR and boost gauges. I think that may help in diagnosis.

Another question, Is is possible that I am getting the CEL because the PCU, plug and play harness, and 7th injector harness are not hooked up? Or, should it be running fine as is, and the PCU, plug and play harness, and 7th injector harness will only aid in SC performance and longevity?

Heres some pics, just because!

 

[the great him]

so let me get this straight, you are running the URD 2.2 pulley(smaller than the stock 2.4) which gives you more boost, and you have the 7th injector kit installed, just not hooked up and running... and you are wondering why its throwing a code? try putting the bigger pulley back on and see if that helps things. also what gas are you running? 89?

 

[4-Ripcord]

Hook up the 7th properly.. it does nothing if its not plugged in.

 

[quicksilvr]

Yup. Until you have the 7th injector setup figured out, put the stock sized pulley back on the blower.

 

[SliderNH]

so let me get this straight, you are running the URD 2.2 pulley(smaller than the stock 2.4) which gives you more boost, and you have the 7th injector kit installed, just not hooked up and running... and you are wondering why its throwing a code? try putting the bigger pulley back on and see if that helps things. also what gas are you running? 89?

Yeah, thats right... Except I'm running 93

 

[the great him]

93!?! where do you live?

and dump that 2.2 pulley and get either the stock 2.4 or a 2.6, your foce feeding that motor more than the injectors can handle...

this is almost as bad as putting 35s on your runner and asking why they rub?...

 

[SliderNH]

Hook up the 7th properly.. it does nothing if its not plugged in.

There's no where to hook it up. Its supposed to go to the two wires coming out of the PCU. Then the PCU is piggy-backed on the ECU wire-harness. Where am I suppose to hook the 7th injector to if the truck won't run when the PCU/ECU wire harness are installed?

 

[sportscarfan]

There's no where to hook it up. Its supposed to go to the two wires coming out of the PCU. Then the PCU is piggy-backed on the ECU wire-harness. Where am I suppose to hook the 7th injector to if the truck won't run when the PCU/ECU wire harness are installed?

Search for Texas Ace over at YotaTech. I think he ditched the 7th in favor of meth injection. I don't know what other fueling he's done.
You will for sure detonate pistons to death if you don't have proper fueling with a roots-blown-anything.

 

[SliderNH]

this is almost as bad as putting 35s on your runner and asking why they rub?...

Haha...Well not so for me. I'm not a tuner, and I don't have anyone to teach me this stuff. I'm just learning it now. This is literally my first truck project. I did a bunch of research on how to do the project, then did it. I planned on being able to run the PCU and 7th injector off the bat and go from there. Since it wouldn't run with the PCU and harness installed I have to back-track. Flame away if you want. Thanks for the tip on removing the 2.2 pulley.

 

[SliderNH]

Search for Texas Ace over at YotaTech. I think he ditched the 7th in favor of meth injection. I don't know what other fueling he's done.
You will for sure detonate pistons to death if you don't have proper fueling with a roots-blown-anything.

He added the meth injection in conjunction with the 7th injector. I don't know if he kept it that way for long or not. I think he's in the process of selling the SC setup and going with a turbo.

 

[the great him]

Haha...Well not so for me. I'm not a tuner, and I don't have anyone to teach me this stuff. I'm just learning it now. This is literally my first truck project. I did a bunch of research on how to do the project, then did it. I planned on being able to run the PCU and 7th injector off the bat and go from there. Since it wouldn't run with the PCU and harness installed I have to back-track. Flame away if you want. Thanks for the tip on removing the 2.2 pulley.

no problem man, yeah just at least put the larger 2.4(if you can find a 2.6 even better) pulley on and keep the 2.2 till you get the 7th up and running then you should be fine with those fuel mods. you can also try getting larger supra injectors and running those. i know some guys on here have done that, but they are harder to tune correctly

 

[BigFishAllDay]

SliderNH,

The point that keeps jumping out to me is that you have mentioned several times that you are using a URD Harness. I know that URD has started selling plug and play wiring harnesses for 3rd gens, so I assume that's what you are referring to.

The fact that the URD controller does not function properly when you plug in the harness indicates to me that you probably have the wrong harness. There are wiring variations from model year to model year, and I'll bet that URD sent you a harness for a different model year.

If I were you I would contact URD and verify that you have the proper harness, if necessary send it back to them so that they can verify this fact.

Your first step in solving this problem will be to get the URD Controller installed in the truck. If you're dead set on having a plug and play install, then pursue that w/URD and make sure you have the right harness. I did a hardwire on mine and spliced into the OEM wiring and it runs like a champ.

In the meantime, I wouldn't worry about re-installing a smaller pulley. Just use the highest octane fuel that you can find, and if necessary run an octane booster as well, and STAY OUT OF THE GAS. It will run fine in vacuum and low boost. Installing a smaller pulley will only net you less boost, which you can acheive with less skinny pedal, saving yourself some work in the meantime.

You are running into problems because you are close to sea level, so there is a higher density of oxygen being pumped into your truck than there would be at say 5,500 ft of elevation where I am. If you were at a higher elevation, it would probably be fine, but at sea level you are going to NEED that 7th to get it running properly...whether you use the stock pulley or a 2.2.

If you need any help on this in the future, feel free to PM me. I've installed the URD 7th and I'm very familiar with it, and superchargers on the 3.4 in general.



Good luck.

 

[SliderNH]

SliderNH,

The point that keeps jumping out to me is that you have mentioned several times that you are using a URD Harness. I know that URD has started selling plug and play wiring harnesses for 3rd gens, so I assume that's what you are referring to.

The fact that the URD controller does not function properly when you plug in the harness indicates to me that you probably have the wrong harness. There are wiring variations from model year to model year, and I'll bet that URD sent you a harness for a different model year.

If I were you I would contact URD and verify that you have the proper harness, if necessary send it back to them so that they can verify this fact.

Your first step in solving this problem will be to get the URD Controller installed in the truck. If you're dead set on having a plug and play install, then pursue that w/URD and make sure you have the right harness. I did a hardwire on mine and spliced into the OEM wiring and it runs like a champ.

In the meantime, I wouldn't worry about re-installing a smaller pulley. Just use the highest octane fuel that you can find, and if necessary run an octane booster as well, and STAY OUT OF THE GAS. It will run fine in vacuum and low boost. Installing a smaller pulley will only net you less boost, which you can acheive with less skinny pedal, saving yourself some work in the meantime.

You are running into problems because you are close to sea level, so there is a higher density of oxygen being pumped into your truck than there would be at say 5,500 ft of elevation where I am. If you were at a higher elevation, it would probably be fine, but at sea level you are going to NEED that 7th to get it running properly...whether you use the stock pulley or a 2.2.

If you need any help on this in the future, feel free to PM me. I've installed the URD 7th and I'm very familiar with it, and superchargers on the 3.4 in general.



Good luck.

Thanks for jumping in on this thread bigfish. I am using the URD Harness, my intention was to save myself wiring trouble, now or in the future if need be. I do not trust myself with wires or a solder iron. So I am kinda dead-set on using it.

At this point, since the main issue is the truck wouldn't run with their harness I'd say its safe to bet the URD wiring harness they sent me does not match my 4runner. Gadget and I talked about that before I placed the order to make sure it was the correct one. Did a VIN verification because the wiring between a CA emissions and a federal emissions is different when it comes to the URD harness. So i thought we worked that out before I ordered it....I sent the unit back to him so he can verify that the URD harness and my 4runner are a match or not, waiting to hear back from him about that.

So my first step in resolving the issue IS installing the controller. So I do need the controller installed in order to have the 7th injector functioning? Thats what you're saying, right? Thats makes more sense than, "Hook up the 7th injector properly." From one of the other posts it sounded like I should have been able to hook up the 7th without the controller, unless they didn't read my OP....

Thanks for the suggestion on keeping the 2.2, finding the best gas/octane booster, and staying off the skinny pedal. Not much else I can do about being at sea level though....Anyway, reassurance is good. I didn't feel comfortable dipping into the power knowing I am lean to begin with. Thanks

 

[BigFishAllDay]

So my first step in resolving the issue IS installing the controller. So I do need the controller installed in order to have the 7th injector functioning? Thats what you're saying, right? Thats makes more sense than, "Hook up the 7th injector properly." From one of the other posts it sounded like I should have been able to hook up the 7th without the controller, unless they didn't read my OP....

Thanks for the suggestion on keeping the 2.2, finding the best gas/octane booster, and staying off the skinny pedal. Not much else I can do about being at sea level though....Anyway, reassurance is good. I didn't feel comfortable dipping into the power knowing I am lean to begin with. Thanks

You are correct. Without the controller, the 7th injector is nothing more than a plug in a hole. It does nothing without the controller.

Regarding the 2.2... all that stepping up the pulley size will do is decrease your PEAK boost levels, from around 8 psi with the 2.2 to 5 or 6 psi w/the stocker. The only time a smaller pulley will make a difference is if you are pushing the engine load and making full boost. Stay off the gas and drive conservatively and that situation won't come up.

(Edit: Even if you do swap back to the stock pulley, that 5-6 psi will likely still be enough boost to cause your check engine light and put you into an unsafe lean condition. The only way to safely drive the truck until you get the 7th running is to stay out of boost as much as possible and boost your octane as much as possible... The octane won't help w/the lean condition at higher boost levels, but it will reduce detonation)

I would have a follow up conversation w/Gadget to discuss the environment where you'll be driving the truck (sea level). Make sure he knows about that and ask if he has a more optimized tune available that he can pre-load for someone in your situation. I'll be he's got something for you.

 

[SliderNH]

Heres what Gadget says, Maybe someone can understand it better than I can...

The 7th injector won't cause or prevent a lean code. Lean codes happen in closed loop high vacuum conditions. Therefore the problem is indicative of a vacuum leak. Most likely because of the troubleshooting that has been done, the vacuum leak is from the throttle body gasket. The throttle body gasket could be installed backwards which might cause the leak.

They new throttle body gasket I put on is the TRD circular one, to replace the "D" shaped factory one. When I put it on I remember it was pretty clear which side went to the TB and which went to the SC...

What exactly does this mean for the supposed 7th injector solution? You guys suggested the problem was from the 7th injector not being hooked up...Does this give anyone other ideas? Is is possible the code could be coming from intake manifold gasket or something??? I tightened the throttle body and SC to factory specs. I don't want to tighten them too much.

 

[SliderNH]

So I took off the TRD throttle body gasket, and put the stock one back on. Since I was pretty sure I didn't install it backwards, I figured Gadget's info could help me figure it out. I compared the two: The TRD one is paper, and the stock one is metal. I figured the material might have something to do with my CEL. Since I was kind of out of options swapped them out, back to stock, did 40.2 miles with no CEL so far. I'm pretty confident I fixed the problem, time and miles will tell, cross your fingers for no check engine light!

 

[4-Ripcord]

Hope that fixes it!