I have 30lb SVO injectors on the modded engine in my sig with the STOCK pump with 56K on it.. When I give it slight gas when normally accelerating it will go fine but when I give it about 1/2 throttle it will bog bad. I scanned it and the O2 go lean like to 80mv. I tried bigger pump shots in the chip but no good. I just hooked up a fuel guage on the rail and with the vac line connected its around 36psi. With it disconnected it goes to 41psi. Now with the vac line connected and I rev the motor I see the pressure jump like 1-2psi and then dive to 29-30 psi. Now if I rev it more it will drop further. Does this sound like the stok pump cant handle the 30lb SVO injectors??? I also have idle issues that I cant smooth out......
Thanks!!

 

My guess would be its time for a walboro 307 or 340 pump. Sounds like when the engine revs up and the injectors pulse more increasing flow through the lines, there is not enough flow to keep the pressure up... hence the more you reve, the more your pressure will drop.

Brian

 

No it doesn't sound like "it can't handle 30 lb/hr injectors"... it sounds like it's defective. Replace it.

 

Check the voltage at the fuel pump connector... should be getting aroun 12V.. if not that could be a problem. On the GN's/TTA's putting a hot wire kit on them to ensure a constant 12.5V is a first recomended upgrade.

Then there is the possibilty mentioned above that the pump may be defective.

Check voltage first... easiest and cheapest fic if its the problem... then you should probably replace the fuel filter... again cheap and easy and definately can't hurt anything

 

So is there any other way to be sure its the pump...will any other engine defects such as valve timing or too small of a TB cause the fuel pressure to decrease due to the vaccuum line on the regulator? I just want ot be 100% sure cus this job is gonna require a new exhaust since the old one was welded on and needs to be cut off??

 

Nope, if your voltage is stong, the filter is clean, and you fuel pressure is set right and you know nothing is colggin the filter pick up(which will require dropping the tank as well) it has to be the pump.