I know this isnt camaro oriented, but you guys here on this board are know as the TBI experts, so I hope no one minds if I ask this...

I have a 95 Tahoe, 350 tbi with 3.73 gears. I bought a already done TBI unit that had all the mods done to it, including a 18 psi spring. At first, I wasn't sure the spring would be ok, until I checked the factory ratings that the fuel pump produces, which is 40-50. I thought it was much less, but I was told by the manufacturer that the pump design changed mid year for more psi...So I left the spring in.

It really seems to run good, except for when first started cold runs really rich and stumbles over itself until it warms. It seems to be getting about 10 mpg, if that. Also, it seems to stumble a bit, and really doesn't like WOT in the least. Actually seems to lose power.

I reset the timing to factory 0 with the wire unhooked, and that only seems to make the power loss worse.

I was thinking a tune, but I really have no idea how to do that on this truck.

Any suggestions would be greatly appreciated.

Thanks!

Shawn

 

I would think that an 18 psi regulator spring would be too much psi without tunning the engine to use that much fuel... I currently have my AFPR set to 18 PSI but my engine is moded quite a bit and I have a tune to compensate for it ... I believe the stock pressure for TBI is from 13-15 PSI.... thats what the BPC tables are calibrated to for a stock TBI engine.

 

Yeah, you need to be able to check & adjust your fuel pressure. 18psi sounds like too much.

 

too much gas. gotta tune for it or lower the psi down. you say it is modded does it actually have an adjustable regulator or just a spring?

 

a stock tbi pump even in a tahoe isnt going to run 40 to 50 psi at all. you need to put a factory spring in it and see what it does.