Running lean and rich at the same time.

Has anyone experienced this before? Running super rich on bank 2 and lean on bank 1. I’ve tried many things with no avail. It is a new/remanufactured engine, that recently replaced a new remanufactured engine due to washing the pistons. New injectors, MAF sensor, up and downstream sensors. My fuel trims are all over the place, any ideas?

 

Are these new injectors oem or eBay specials?

 

Fuel injector clinic.

 

The only time I’ve ever had issues with rich on one side and lean on the other were from fake oem injectors just not spraying correctly.

 

Replaced the injectors due to running rich on bank 2. Now I’m lean and rich.

 

TTT

 

Just shootin from the hip here, but any chance the O2 sensor harnesses are reversed? The ECU leans out 1 side, because it thinks it’s rich, but it’s leaning out the wrong side. At the same time, it’s richening out the other side, but it’s reading the lean side, so it just keeps on getting richer. Don’t know if all that’s possible, but just a thought that came to mind.

 

Lower intake manifold vacuum leak?

 

Fuel pressure is my suspect.

If its low, the one rail will get higher pressure than the passenger side.

 

I was thinking about a vacuum leak as well. Also had someone tell me to check the fuel pressure regulator but I didn’t know if it would have that kind of effect?

 

TTT

 

.

 

I would troubleshoot one step at a time. If the wiring were flip flopped then you would be getting one rough as hell running engine considering the firing order. Check the fuel pressure in the rail first to eliminate anything from the fuel pump forward. What size are your FIC injectors? Are you S/C or turbo? Is this a 2TR or 1GR? I have a complete set of stock TRD and supercharged injectors in my garage that are good, but I think more diagnosis is needed for you.

 

Post in here.
https://www.tacomaworld.com/threads/re-updated-trd-magnuson-4-0-supercharger-tips-tricks-and-mods.518932/page-1154#post-22320005

These guys plus @JustDSM can get you sorted.

 

Good one

 

1g NA and the injectors are the right size.

@JustDSM has been helping me with this and I think it has him scratching his head as well.

 

What is the fuel pressure in the rail? And you can confirm no vacuum leaks? What about swapping ECUs? I had one fault out one bank of injectors.

 

Ok isn't there just one fuel source? Low fuel pressure will make it run lean both sides, liquids don't compress well. I would like to know the methodology of how it's being tested.

 

The injectors fire twice during each cycle. So firing order 1-2-3-4-5-6 Question, how was it determined that is rich on one side and lean on the other?

 

Yes. Pressure would be universal. However, it may not be high enough to keep up with the firing order of the injectors and when it exceeds the fuel pump capability then those cylinders run lean. It probably isn’t very rhythmic as well which would explain why the lean/rich scenario is jumping all around. I would put a pressure tester on the rail. I would be willing to bet your regulator or fuel pump is malfunctioning and not able to maintain over 40psi in the rail.