Supercharger going lean

I have a supercharged Toyota Tacoma it’s a year 2021 and I was curious if anyone had any inputs on why it was running lean? I want to add a smaller pulley and new fuel pump but I am very confused on why I seem to be the only person having this problem with my truck. I did do a regear because I’m running on 35’s not sure if that is a problem or not. I am also looking for some advice on things if someone knows why I’m running into these problems. Thank you

 

I don't know, but it sounds like many are going with custom tunes for FI, I would explore that, if you haven't already.

 

Who is FI?

 

FI means Forced Induction

How do you know that it is running lean? Check engine light? live data? datalogging?

 

The truck has gone into “lit mode” where the truck will basically stop running I’m guessing for safety reasons and I talked to my guy who knows Tacomas very well and he said the main reason it would go into that mode would be due to the truck going lean as well as I have ran a diagnostic on it showing the engine wasn’t receiving gas

 

"Limp mode"

 

if someone adds major aftermarket engine mods they should know how to work on them

 

Lots of things can cause limp mode.

It could be that your fuel pump is failing, especially considering the additional load on it. You have the Magnusson or Procharger?

Also, if your truck is going lean enough to cause "limp mode" you should also have lean codes stored in the PCM (P0171, P0174)

Vacuum leak, bad MAF sensor, bad O2 sensor can also cause lean issues

 

My questions & comments to the OP:

1) What kind of supercharger is it? When was it installed? Who did the tuning? Do these engines require a larger fuel pump or bigger fuel injectors when supercharged? Are you running out of fuel at high RPM or load?

These are all questions you must be able to answer. Seriously.

2) Unlike late model Ford Mustangs where aftermarket superchargers are quite common (I have one), supercharged Tacomas are very very unusual. That being said and having 30+ years of experience, I can tell you this --> your Tacoma is *never* going to run correctly unless it has been custom-tuned by an absolute expert on a dynamometer. Again, I ask you Who did the tuning? What kind of tune do you have?

3) You cannot just bolt on a supercharger without over-riding the OEM tune and "flashing" a new tune to the PCM powertrain control module. Note when I say "tune" here, this does not mean like adjusting the idle screw on an obsolete carburetor. Tuning means the engine is data-logged via software and a device that measures all kinds of parameters - the most critical being Air Fuel Ratio, timing, throttle position, engine timing, fuel pressure, fuel trims, etc... The PCM is completely reprogrammed.

A custom tune, properly done, adjusts things like Fuel Injector Duty Cycle, timing advance, and other parameters so the engine runs correctly. Misfires and knocking are the enemy of forced induction (FI). These are caused by lean conditions.

4) An engine that is running lean is bad. A supercharged engine that is running lean is a connecting rod looking for a place to exit the engine block.

5) Your rear differential and tires have nothing to do with this.
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My suggestions:

* Answer the questions above so others here might be able to help you.

* Post up your DTCs diagnostic trouble codes. What are your AFR's at idle? What are your Short Term and Long Term fuel trims reading right now? I'm guessing your check engine light is illuminated. And you darn sure better have an OBD-II code reader.

* Do not even think about wasting any more money on a fuel pump or smaller pulley until you resolve your lean condition first. Guessing and just randomly replacing parts is *only* going to make it more difficult for you.

 

Supercharged Mustangs FTW.

 

Highly suggest data-logging to see what is really happening. OBD Fusion with Toyota PID’s / OBD2 dongle. You can monitor your trims, long term and short term, as well as your high pressure fuel pump. Don’t throw parts at it until you know what’s up.

 

I often suggest this and sometimes get heat for it, but my thought remains the same, as @BigCarbonFootprint mentioned, there's just too much going on to pay a shop to bolt it up and let it eat.
I supercharged a car years ago, and since we did the install, we knew how to work on it, which came in handy as it took many nights in the shop to get things ironed out,,, including changing out fuel pumps and pressure regulators.

 

I see that that little centrifugal doohickey there.

 

By way of contrast as compared to a Toyota Tacoma, supercharging a Mustang is quite common and there are shops all over the place that will dyno tune your Mustang once supercharged.

I have a 2014 5.0 GT Mustang that I voided the warranty less than 1000 miles off the dealer lot and had a Roush supercharger and long tube headers installed at Brenspeed Motorsports (a top 5 Ford tuner in the USA) in Dallas TX.

Made 550 RWHP on their chassis dyno after two licks on the dyno and ten years later I have still *never* thrown a check engine light. AFRs are perfect at all times. Fuel trims always stay within +/- 3%. I can run in heavy stop-n-go traffic with the AC blowing and not overheat, misfire, or throw any kind of DTC code. And then I can get sideways in 3rd gear on a freeway on ramp.

You wanna supercharge your engine? YOU BETTER BE ABLE TO TUNE IT. CORRECTLY. PERIOD. END OF DISCUSSION.

Anything else is a complete and total waste of money and time.

 

Indeed. Only made 838 WHP, so clearly I have some work to do.

 

Shops won't even go near mine after the SC addition for the most part. Only Toyota off-road specific shops that are familiar with them can sometimes be persuaded to if I sweet talk them enough. Hell I had fire stone refuse an ac service because of it.

 

I'm think these guys might be a little harsh with you!

My Advice:

Find a good performance shop/tuner near you and get it diagnosed and if nessesary get a dyno tune to correct the problem. Tuning is not rocket science (especially these days with the new programming software out there) there are a lot of very good tuners across the country. Remember, You don't have a race car/truck so programming it to run in safe parameters is not that difficult for a decent tuner.

 

I dunno about harsh. My Dad told me more than once that the truth can hurt your feelings, but it is always the truth.

Anyway, we totally agree. OP needs to be data-logged followed by a dyno tune. And, yes, I agree with you in principle. Dyno tuning is not that complicated. AFRs need to be 12.5 +/- at WOT and under full load. Knock sensor count needs to be 0. Blah blah blah.

OP needs to find one who is familiar with tuning Toyotas. This is not something one can resolve otherwise.

Cheers!