TBI injectors problem

**kur4o** · 06-06-2023

I have some TBI injectors that seems to not perform well. The spray pattern is not a fine mist but sometimes you can see a drops. Also when they get hot, they produce some growling type of noise that can be heard quiet loud.

I don`t have any experience with these so don`t know which is normal.

Do these seems shot and can it be cleaned with some fuel additives. How about bumping the fuel pressure. I got 3bar pump already and now the pressure is around 1 bar. WHat is the max they can handle and will it cure the course mist pattern.

**1project2many** · 06-07-2023

The maximum pressure depends on the application. If they are "regular" TBI injectors that typically operate at 9-13 psi they can usually be used at pressures over 30 psi.

Is it difficult to obtain another set of injectors? If the spray pattern is not good I usually move on to another set. Is the growling noise occurring in the vehicle? Do you have a way to scope the injector circuit to look for issues when the injector is growling?

I have not had much success using most additives for cleaning. But other folks may have a different recommendation.

**kur4o** · 06-08-2023

1project2many, Thanks for the input

At cold engine start, growling is very weak and gets noticeable, after getting a good warm-up and heat soak, The noise is really loud, I had to trace it with a stethoscope to find the source and was very surprised it comes from injectors. Unfortunately no scope can be used on injector drivers.
I suspect the injectors are stock 5.7 ones, but have no way to confirm. Good OEM stock is hard to find and really expensive, while aftermarket is hit or miss. I am trying to save these ones as much as possible.