I have an 03 Silvy SS, LQ9 with a radix. Recently my AFR was a little erratic. I think my inline pump is shot and plan on changing it this week. I installed a new fuel pressure gauge and it is reading from 68-72. Isn't this high? Why would it be this high especially if the in line pump is bad. Appreciate your thoughts.

 

that is not high as long as you have a returnless system. which way was your afr erratic rich or lean? also what is your fuel pressure at wot. a weak pump will keep up at idle and low load but will not at wot and 6000 rpm's.

 

I have a return system. The afrs jump from stoich to lean when at idle and when I go wot, it goes lean as rpms increase. I will change the pump and see how it goes. I do have a concern that it is that high at idle. not sure if I am missing something. Seems to run fine, just a little weaker at wot when it goes lean (it was a nice 11.5 and now creaps up to high 13s, low 14s).

 

Whoa, careful with that. I wouldn't thrash on her knowing that your AFR is going into the 14's being supercharged. Your FP for a stock boost referenced return style is high IMO. Bad FPR by any chance???

 

Not sure about the bad FPR. I will try installing the new pump and see what that does. Anyway to test the FPR?

 

changed the pump and that wasn't the problem. I am going to try to change the regulator as per Krambo's suggestion. Any other ideas?

 

Did you ever find the problem with this? Im curious to know.