Code P0171 supercharged

Alright, I’ve searched and searched and can’t find anything to help with this. I’ve had my supercharged 99’ Tacoma for 2 years now and for the last 6 months maybe more it’s been throwing code p0171 off and on saying it’s running lean in bank 1. I’ve changed
O2 sensors, MAF sensor, fuel filter about a year ago, fuel injectors about a year ago. Checked all the hoses for vacuum leaks.
I don’t know if the supercharger is messing things up or what. Anyone that’s dealt with a similar issue? It all started after I put a cold air intake on but I’ve since put the stock box back on. The light doesn’t always stay on either, it’ll sometimes come and go.

 

Which engine?

 

It’s the 3.4L

 

there a white plug that routes to the iac, the check valve do you have that in the sc

 

Check the brass nipple on the SC. Located at the rear of the charger, facing the firewall.

 

Have you tried spraying brake cleaner or starter fluid around the intake area and the vacuum hoses?
If there’s a vacuum leak you hear the engine run different when it pulls it in.

I chased the same code on my ‘03 with a 1st gen gray supercharger for a long time. I bought a sorta diy paint can smoke machine and was able to narrow it down to a very small hole in the back of the supercharger. I filled it with JB Weld. The other leak was the intake gasket.

 

This is the supercharger I have. I’m not seeing a brass nipple, also not seeing a white plug that routes to the IAC. But I’m gonna go get some starter fluid and start there.

 

An unlit propane torch is a better alternative than starter fluid (as you don't end up with the stuff soaking the engine bay or hot exhaust components). Don't use brake cleaner- burning it can kill you.

 

Good advice!
The brake cleaner will eat your paint even if you get away with out it killing you too.

I wish Id thought of the propane torch before.

 

Something is causing an excessive too lean condition. Be patient when looking for an exhaust leak.

 

if the CEL was more consistent it would be easier to test. If this was me this is what I would do. I would get an OBDII scan tool capable of storing live data and off loading it, Bluedriver is the tool I use for this. Put the scan tool onto the port in the cab and make sure it connects to your smart phone. Select live data and go through the list of what you want to monitor and drive the truck. Hopefully the CEL doesnt come on. Save the data and export it and use this as a baseline. Keep repeating the testing until the CEL pops and try to remember apx how long into the drive it popped. There is LOTS of data and you want to find the time frame in the data list of when the CEL popped. See what is different.

The question I have about boosted motors is how the fuel pressure regulator on a stock motor handles a boosted motor. I am assuming that the vacuum diaphragm on the fuel pressure regulator can go from a zero intake manifold pressure (WOT is actually a positive 14.7 psi air pressure) on a normally aspirated motor to a positive pressure, atmospheric plus boost, or is there a one way check valve in the line that goes to the FPR? Just thinking out loud here.

 

So did you ever find out where the leak was?

I have the same supercharger and the same code.