Hey guys,

Last summer I replaced my leaky stock injectors with Design III 22 lb injectors. This fixed my rich o2 code. I choose 22 lbs on the advice of the seller, and I've since learned that I really should have stuck with 19 lb injectors. It's been bothering me.

Now my car already struggles with poor economy and low RPM bucking, and I can't fathom finding a proper EPROM with 22 lb injector constants (have advertised in the classifieds). Would it perhaps be best to rip those injectors off and replace them with 19's? I figure I could sell those 22's for a reasonable price and end up not losing much money.

Fuel economy is important, as is a smooth running engine. If I can't achieve this with my current injectors, what do you think I should do? I do have a Holley AFPR, and thought I could solve it by lowering the fuel pressure, but the knowledgeable people here mentioned that under such conditions, the fuel will not atomize properly and further contribute to the problem.

Thanks in advance!

 

IMO ... You will need a custom prom to run your 22lb injectors on a 305, unless it has been bored over, still you will need a 350 prom... better to just go back to 19 lb injectors... what is your MPG? ... you should be getting at least 20 - 25 mpg

 

It would probably cheaper to sell your 22lb. injectors and buy some 19lb. than to have a custom chip burned. Who sold you the 22's? If you bought them from a company you should ask them to cut you a deal on a set of 19's since they gave you bad advice.

 

Thanks for the responses,

It was a company that I got them from. I won't mention who, but maybe I'll talk to them.

I was getting poor economy with my old injectors, and it never got much better with the new ones, which was disappointing. With mostly highway commuting to work, I get under 20 mpg. I'm not sure what a well tuned 305 should get, but I have to fill up an aweful lot.

 

Too large of injectors will ruin your fuel economy. Some people don't care but if you use the car as primary transportation it makes a difference. You're dumping more fuel into your motor than it needs. You should definately lobby for a discount on a set of 19s from that company.

 

I'll see what I can do about getting 19's. I've ran the fuel pressure from low 30's to mid 40's and I don't see much difference in economy or performance. What kind of mileage should one expect from TPI? I remember I used to get 26 mpg (imperial gallons) on pure highway, which seems acceptable, but it's terrible around town.