i think I have an ongoing FUel issue. Well I'm thinking it's fuel. Ok. I used a fuel pressure tester and got these numbers 40 at crank, 31 while running, 40 when I remove hose from pressure regulator which was replaced. The fuel immediately drops to 0 when turned off, so with these numbers I replaced the pump and fuel injectors with denso 24#, replaced icm and fuel pump relay. The opti was replaced a few months ago also . Originally when i got the car a couple of years ago the genius I bought it from used liquid wrench on the fuel filter so long story short I had to cut the line running from the filter to the engine and replace it with rubber fuel injection hose. I didnt really notice the issue when I had to cut the line back when it's just been the last 6 months or so. I have no clue what is going on I have to prime the car to get it running and I am getting zero DTC codes. Sorry for the novel but I need to get this resolved thanks

 

31 while running is way too low. Fuel immediately dropping to 0 indicates the check valve in the bump is bad. Not a do or die situation but it helps the car start easier by keeping pressure and therefore gas in the fuel lines.

 

I just put a new airtrix pump in too thinking it resolve it. Can't find the receipt either. I would have to replace the pump again? I'm reading the check valve can't be serviced. Would any loose rubber hoses on the lines to and from the pump cause a fast leak like this as well?

 

A leaky return hose can cause the drop as well. A leaky feed hose would cause low pressure, but you should smell gas either way. If the check valve is indeed the problem, you don't need to replace the pump. You'll just have to prime the system before you start it up. Is the 31 lbs while running the reading you got after replacing the pump or before?

 

failing fuel pressure regulator can do this.

 

^ He replaced that too

 

if you have not seen yet look at this 4th Gen LT1 F-body Tech Articles when testing for pressure loss i used some card board folded over and put it over the plastic line and then clamped it off using wide vice grips. the card board spreads the pressure from the vice grips to reduce the chances of cracking the line. you have rubber so you should be even better off for the pressure side. you can and i have gotten faulty new fuel pressure regulators and have read of failing new fuel pumps so keep that in mind. dropping to 0 so fast indicates injectors are probably not the cause of this issue.

 

Any Photos of the components on the pump? So I can identify what is what on the pump as well?

 

fuel pump relief/check valve is not serviceable. its inside the pump.

 

The 31 was prior to installing new pump and it still seems to be the same. I'm wondering if that rubber line from the filter to the engine could be the cause? The priming gets old sometimes it doesn't catch, stumbles and shuts off (embarrassing) I am going to give the new pump a shot I found my receipt. I have no clue what lines on the pump are what, I just know the flex hose.