I recently swapped my 305 out for a 350 and retained my TBI. it runs like ****, and i have gone over every possibility, Is it possable that my Stock TBI is not getting enough fuel and air into the 350? The timing is correct, no check engine light, no vacuum leak and all electrical connections are plugged in. Some help from the TBI masters around here??? I am thinking the Holley 670 cfm TBI may solve my fuel issues, due to the larger fuel and more air as well.

 

my guess would to datalog and then tune it or u can try to swap the chips not sure if theres a difference in the chips tho

 

swapping to the 350's stock 55lb injectors would probably fix that problem, but if you had a vafpr you could fix it too, but if you've got the tools to do the datalogging first, go for it, there's always the possibility that that's not the problem.

 

You need a new chip . . . badly.

 

if he's got the 305's 40lb injectors on a 350 that came oem with 55lb injectors, why would he need a new chip?

I'm both asking this because I feel it may be unnecessary, but also because I'd like to know just how different the fuel maps between the 305 tbi and the 350 tbi are.

the reason why I ask that is because the fuel differences needed(I would think) would be covered between the different injectors to their respective engines, assuming both were running at the same psi.

 

Right off you need larger injectors and/or increased fuel pressure. The 305's ran 55#/hr while the 350's ran 61#/hr or 68 #/hr injectors (dependent upon the year/model).

With the proper injectors the engine will run much better. Although, the correct calibration will also help. Is the 350 a stock GM TBI engine? If so you may be able to find a stock cal for it that along with the proper injectors will run quite well.

If it isn't a GM TBI engine, you may need to not only upgrade the fuel flow but get into some DIY tuning. With this it is possible to increase the fuel pressure to achive a higher fuel flow. Then tune for it.

As a side note I'm running an '85 Camaro LG4 engine (305) with the 350 61#/hr injectors. At stock fuel pressure it runs OK. Have fuel to about 4,800 RPM. After that it starts to run the injectors static.

RBob.

 

sorry bout that, had my numbers wrong on the injector sizes. not my fault though, just read those numbers 3 days ago from a site that of course now I can't find...but I just looked em up on turbocity, 305's came with 55 and 350's had 61's and 68's. my bad.

 

yea you should have no prob. getting it to run with the right injectors and some timming,and idel adj. read my signature