2G Fuel delivery issue

[bigdnno98]

ok so have developed an issue lately. Started out with a lean spot in the tune around 4400rpms. I basically just tuned it out by targeting a richer AFR in the DA table. Now, when I left the track wed my fuel pressure was lower than normal. Around 36psi with the vacuum live on so prob around 40psi without it on. I was running low on fuel and thought that may be it. Went to the gas station today and got some fuel. Went to the regulator at the gas station and turned it back up to 44psi without the line on. When I did that fuel trims shot crazy high for some reason. I shut the car off and it didn't want to start back till I lowered the fuel pressure back down to 36ish with the line on. My Walbro 450 is about a year old, my Walbro 255 is about 4 months old, my aero motive FPR and liquid filled gauge are about a year old, my injectors were just cleaned and flow tested about 3 months ago. Any ideas where to start troubleshooting this without just throwing money at it? Fuel is e85.

 

[inthemidst]

Check your fuel filter.

 

[bigdnno98]

Already did. Looks brand new.

 

[bigdnno98]

Cleaned the fuel filter, pulled the FPR apart diaphragm looked fine, pulled the injectors. Gonna have them flow tested locally. Also put my spare gauge on the FPR. If none of this works gonna have to check the fuel pumps I guess.

 

[97_4g63t]

Are both of your pumps rewired? Individual relays or one? Maybe one died or popped a fuse. Voltage good?

 

[bigdnno98]

Both pumps are on separate relays. Volts are good. Both pumps seem to be running.

I'm thinking it was either the FPR gauge or the injectors. It's weird that fuel trims went crazy positive when I increased fuel pressure. Really the opposite should have happened. Trims should have went negative I would think. Makes me think the added fuel pressure is making a suspect injector stick closed.

 

[bigdnno98]

Injectors just checked out good. I pulled the AFPR the other day and took it apart. Diaphragm looked fine. Guess I need to pull the 450 out of the tank again and check it out. Can't think if anything else it might be. I'm going to put the injectors back in tomorrow probably and see if it mysteriously fixed itself. . If not I'll pull the 450 in tank and see if I can see anything going on with it or the hanger. Guess I may be ordering another 450. Not surprised it didn't last more than 1.5 years if it is the pump. Walbro doesn't have a great reputation.

 

[bigdnno98]

Well, got the injectors in and started the car. Set the base pressure back to 44psi and trims are perfect. Was either an injector or the AFPR gauge.