Jacob Wiseman

Hi I have an 85 g20 with a carbureted 305. Is it possible to take the efi system off a later year model 305 and make it work in my 305?
Thanks, Jacob Wiseman

SteveROntario

There are lots of aftermarket kits available.

Jacob Wiseman

Yes, but I didn't ask that, I know there are very expensive aftermarket kits.

oilcanhenry

Might be possible with a late 80's-early 90's pre OBD II TBI injection unit, but you would have to install a fuel pump capable of maintaining 55-62 PSI for the injectors to operate properly. and an intake manifold too. You'd need an ECM for the system as well. Likely need a new distributor and coil too. If you can get good used parts it might be worth it. Also an air filter that would fit the TBI unit. What kind of carb do you have currently?

Edit: My mistake on the fuel pressures. it should have 11-17 PSI to operate the injectors on a 87-94 TBI unit. I was thinking of the injection for CSFI & CPI Vortec engines fuel pressures.

tech2

the aftermarket kits are the cheapest, easiest and smartest way to do this. or just buy a van with fi. Even if you had donor vehicle the work involved is significant.

I know the advantages of fi but don't get why go to all the work...do you need a project? tbi isn't much better than a carb.... so you'd be into multiport

oilcanhenry

Or switch to a Holley carburetor. I had a hunch that OP's motor was factory with a Rochester Quadrajet, and I was correct. Worst carburetor ever built. Holley or Edlebrock would likely make a great difference.

tech2

and it would be running in an hour

Jacob Wiseman

I was wondering about efi retrofit as it ran really rough and accelerated poorly, at the time a few months ago. But 2 months ago the water pump failed and while replacing the 4 v belts I noticed an empty pulley and saw it went for a.i.r. or smog pump, I bought and installed that belt and the power\acceleration issues I had were gone, and when doing a tune up saw my van got a remanufactured carburetor in '06 so all is well now.