TBI FUEL SYSTEM

Fuel Injectors

Although it has been the subject of a few arguments, I think that the basic understanding is that the L03 in Camaros and Firebirds came with 45 pound per hour (PPH) injectors.

These are good for normal use and some mild performance mods, but with any substantial changes to the engine, you will either need larger injectors.  There are a lot available from other GM cars and trucks.  Here are a few:

Flow Rating

Application

Color Code

Part Number Markings

GM Part Number

40 PPH

305/5.0 Liter L03, Camaro & Firebird (stock)

Green/White

GM 5235279 *RPD

 

55 PPH

350/5.7 Liter Pickup

Orange/Black

GM 5235206 *RPD

 

65 PPH

350/5.7 Liter Cop Car

Yellow/Brown

???

17112412

80 PPH

454/7.4 Liter Big Block Truck - Later Models

Blue/Black

GM 1708430 *RPD

17112560

90 PPH

454/7.4 Liter Big Block Truck

Dark Red/Dark Blue

GM 5235231 *RPD

 

 

Fuel Pressure

Adjusting the fuel pressure on a TBI car can do a lot for performance.  It can make the injectors "think" they are larger by spraying more fuel out at a higher pressure.  Adjusting fuel pressure can also fix a common problem of having the wrong air/fuel mixture.  For example, if you have done a lot of intake and exhaust work that makes your car breath a lot better, your stock amount of fuel may not be enough to keep your ECM happy.  (You will be having a lean condition - not enough fuel for the amount of air)  But, if you increase your fuel pressure a little bit, it may correct the lean situation that you were having.

Although this does work, I cannot tell you enough how THIS DOES NOT REPLACE PROPER TUNING!!  This is a very important fact.  Although fuel pressure adjustments and even fuel injector changes may improve the drivability of a car with modifications with an otherwise stock chip, it will NOT replace a properly calibrated EPROM.  You will never reach your maximum potential without custom chip burning.