I've been watching my fuel pressure, boost, o2's and KR like a hawk, since I'm running my sts on a stock fuel system. I've never seen a lean condition at 5-6psi and my o2's are at 890+ at WOT. I know they're just the stock 02's but they're better than nothing. Anyway I was told that my fp should drop as boost increases, or at lest level off, around 62psi. WRONG! I played with the wg this weekend and got the boost up to 10psi. It didn't lean out at all, but I think the reason being is because my fp climed to a little over 70psi!

Do I have a freak fuel pump, or are these factory regulators boost referenced? BTW, at 10psi, it still didn't lean out per the factory o2's.

I have new injectors on the way, but I'm debating whether or not to upgrade the pump. I'm sure the bigger injectors will drop pressure some, but who cares if the regulator increases pressure with boost.

 

Nobody wants to comment on this? Any one experiencing this?

 

 

Didnt comment on it cause I dont have any direct experieince with it. When I had the stock injectors with a cam and spraying a 100 shot my fp stayed right at 61ish at WOT even through third. I dunno maybe your truck has a freak pump in it. I owuld run it till it croaks then put a nice aftermarket one in it. What year is your truck if its an 03+ you can do the intank pump if not you would have to get a new intank pump and then get an inline pump cause I doubt the new pump that you get owuld be a freak like the one you have now.

 

Does that mean is a freak? Or boost referenced? I know I'm a freak, but that's beside the point.

BTW, its a 2000, and when I bought it used from a dealer, they said they replaced the fuel pump. It wasn't performing up to thier standards (whatever that means), and I assume it was just a factory pump, nothing special.

 

it is boost referenced....the stock FPR will add fuel pressure as it sees boost.

 

wait a second, you are running the stock fuel pump? WOW you are a freak if you are seeing that much pressure at the rail.

 

I know, that's what I'm saying! I'm going to hook up a non-in dash gauge tomorrow to verify. But I see a tick over 70psi at 10psi boost.

I think it could just be the fact that the fuel is going through such a small orifice in the stock injector. I'm willing to bet once I get bigger injectors on, it will have less resistance, and the pressure won't nearly be as high.

 

I have the 44# injectors and an in-line Walbro 255LPH. I see 67+ psi at WOT at 6 psi boost. I have not bothered to see if it is higher at 10 psi but I will check when I get a chance.

 

Ok, that's about what I see at 6psi. I feel better now. Time for an upgraded fuel system. Bring on the boost and broken trannys.