3.4L supercharger

Well…the P0171 story continues.

I took my truck to the local Toyota dealer to locate the vacuum leak.

They diagnosed it as the 7th injector gasket needing replacing. I ordered a new gasket, installed it and started the truck. The Long and Short time fuel trims were still super high and the hissing sound is still there just after the engine is turned off.

The dealership's diagnoses was wrong.

I swear I have terrible luck with bringing vehicles to a shop for service. At least this is just a misdiagnosis and not something far worse which has happened before.

I repeated what I've done at least 4 times now -
I took the supercharger off and blocked off all airways and smoked tested it. It's appears solid.

I blocked off the engine airways and smoke tested it. This time the results were different. There was smoke coming from the driver's side crank case vent where the vent enters the valve cover. I'm wondering if this is press fit or screw in?
If it's press fit I assume I'll need to replace the valve cover.

I also noticed a leak coming from the intake manifold.

I created this thread as well:
https://www.tacomaworld.com/threads...ase-vent-intake-manifold-vacuum-leaks.797413/

You can see both in the video below bubbling. I think my smoke machine ran out of oil for smoke at this point.
https://www.youtube.com/watch?v=ILPP5c35Uqg

 

Few quick questions. I currently have an AutoMeter boost gauge thats manual. I'm thinking I want to go with an electronic display because I'm having trouble gauging exactly what my boost is based on the angle that I look at the gauge. I'm finding now that I want to be a bit more precise I'm lacking in that area. Hoping to make the swap fairly easy, its one that just has power for lighting and a boost line ran to it. Any suggestions on one to get? I know a lot of you swear by the innovative all in one, but since I'm happy with my AEM AFR gauge and other gauges I just want one that does boost. Any thoughts on either of these?

https://urdusa.com/aem-30-4406-digital-boost-gauge-35-psi/

https://urdusa.com/innovate-3851-mtx-u-vacuumboost-shift-light-gauge-kit/

This one from innovative has a "shift" function, but I'm in an auto as a note.

Do these require more things ran to them than just power and boost?


Second. As I'm getting more into my vehicle and the intricacies of it, I'm curious about overdrive vs no overdrive. I feel like I have a lot more power when overdrive is off, obviously as I can hit much higher RPM/s. That being said, when I do, my boost goes from around 9.5 PSI (where I top out) and drops to about 5. That being said my truck feels so much faster, and even on my scan gauge I see that my gross horse power is more. Is this just something to do with the downfall of not having much control with an automatic? Anyone else experience this with their boost dropping. I'm super happy with how things run, its interesting because my truck is in such a nice place so I'm reluctant to nit pick it that much but I cant help but wonder. Its almost like I have two options, I can go out of overdrive, or just give it more gas and head into high boost, but I definitely feel like there is less torque, power, etc. Is there something else scan gauge wise I can be looking at that can help me figure out what is going on, or is that just the way it is for us automatic folks?

Thanks all!

 

I agree, an electronic gauge just sweeps more smoothly and is easier to read. I have this Autometer gauge and love it.
https://www.autometer.com/2-boost-vac-30-in-hg-15-psi-fse-phantom.html

 

How do the electronic ones connect? Is it not just a boost port (which I would assume its not) just wondering how much re wiring I need to do, haha.


EDIT: Looked at the instructions and its a MAP sensor that comes with it? Is there anything against keeping this inside the cab? I have a painless performance box that gives me plenty of extra ignition and constant power so I'm all set there and have the boost ran from my other gauge, just avoiding going through the fire wall for the thousandth time. The instructions has it in the engine bay, but any reason why you shouldn't ?

 

My innovate gauge has a separate module that you mount in the engine bay that you run the boost line to. Then there's a cable that connects from that to the actual gauge in the cab.

 

If anyone wants a discounted URD MAF+T calibrator I have one for sale

 

Are you actually able to read it when you're driving in boost anyway? Seems unsafe. It's not really a precision thing after you tune, which should be done by datalogging anyway. What are you looking to gain here exactly?

https://www.aemelectronics.com/site..._instructions/30-4406_Digital_Boost_Gauge.pdf
+12V, GND, pressure sender. Others are optional. "In order to use the gauge, only the red and black wires need to be connected. The white and blue wires do not need to be connected."

OD on = 4th gear so you will feel more torque with it off (3rd gear). Less load in lower gears, so lower boost. Not sure of the rest of your setup but the higher PSI could be pulling timing as well. Optimal shifting points are always considered when you want to go fast - you need a dyno plot if your seat dyno isn't working.

 

The MAP will require a source of vacuum so you'll have to go through the firewall for that if the MAP is inside the cab. It seems like running a wire through the firewall is easier.

 

From what I recall the plug on the end of the map is kind of fat and more difficult to run through the fire wall than the tube for the vacuum source. My firewall has a bunch of additional wires going through it making it more of a challenge which may not be the case for others.

 

Copy yeah thats what I'm worried about. I know I could do it, but this is me just thinking about this later on. I may just hold off for a bit. The thought of redoing any of that wiring I've done makes me want to puke, haha.

 

I've been chasing P0171 for over a year now.
I did these:
new fuel filter
cleaned MAF
new O2 sensors - fore and aft (there's only 2 O2 sensors). I don't know how the P0171 knows Bank 1.

I also tried to put a fuel pressure gauge on it but no easy spot to connect it. I ended up putting a lot of air in the fuel system and the CEL went off immediately. After sputtering for a mile, the CEL came back on.

That told me lower fuel pressure removed the CEL.

My LongTerm (LT) fuel trim is -30 (very high) and that's probably what is triggering the CEL.

I suppose the vacuum leak is the problem?
My fuel mileage was ~17mpg before and after this P0171 came along. The Taco runs just the same as before so I'm not willing to spend a fortune fixing it.

 

Only other thing I can think of would be you need a new MAF. Hook up an OBDII reader and find out what it's reporting.

 

When I first got my truck in 2016 it started tossing a P0171, I was brand new to Tacomas and anything DIY in general back then so I took it back to the Yota dealer on the 30 day warranty....they had the truck for over a week and couldn't figure it out. They had some master tech come in and he was able to pin point it to a leak on the supercharger where the EGR port was capped.

Looking back I dunno how a bunch of regular techs couldn't figure that out, a smoke machine or the like probably would have revealed it. Anyway, yeah I would check for vacuum leaks. Super common source of the P0171 code, especially with how aged the vacuum lines and seals are now on most of these trucks. Or the MAF like mentioned above.

 

Thanks. That's not a bad idea. Also, forever (i've owned 2 of these trucks), when the truck is warmed-up, it's hard starting. It's like the plugs are fouled. Then it starts.

Sorry. I just realized I high-jacked the SuperCharger thread.

 

Hindsight is 20/20.

 

Just incase anyone is interested in going stand alone haltech for your supercharger
SNPSPEED.COM is having a group buy

https://www.tacomaworld.com/threads...ercent-off-snpspeed-com.800661/#post-28694436

 

Boutta do it at 400k, you'll be fine

 

Anxiously waiting. My current S/C is making noises, it will need a build soon. Would rather get the new one ans sell the old one at a good deal to someone knowing it needs a refresh.

 

Absolutely the way to go. Don’t waste your money on an expensive rebuild.
My last full rebuild was 2100.00 with rotors.
New supercharger bearings are rated at 20k (not 12-15k) and rotors will be turning 30 percent slower because they 30 percent bigger and a 160 degree rotor twist instead of 60 degrees.
Also will take less HP to run and will create less heat.
And full boost should come on much faster too at lower rpm’s.

The last update I got was as early as July or as late as August.
It’s in the final development and fine tuning .
Then an inventory Has to be created.

I’m definitely buying and waiting and will post a new information.
With fuel and timing and smaller pulley 300hp rear wheel should be easy I’m thinking

 

Im thinking about selling mine as well.

I’ve been chasing this P0171 code forever. Fuel trims have been super high.

I’ve spent $445 on diagnostics at a dealership that miss diagnosed and a local shop that actually tried to find the problem and in the end said not sure, probably a vacuum leak we can’t find.

so, to isolate the supercharger I put the truck completely back to stock. I’m waiting on a new fuel pressure regulator hose and pcv hose to take a look at the fuel trims with it in stock configuration.

Edit: and I can use the money for the sold SC, 7th injector and AFR gauge for some massive dental bills I had in the past year