Will my stock 1998 305 TPI fuel system perform ok with 24lb injectors? Stock is 19lb injectors, but I'm curious whether 24 would be ok or create drivability problems. It looks like there might be 24's in the car (not possible) which means they were replaced and I'm not sure the fuel pressure is high enough for a 24.

I could use your technical insight.

thanks,

 

If all you change is the injectors, it will not run right. The computer has to be programmed for the size of the injectors you are using. Fuel pressure will be the same no matter which you use unless you have an adjustable regulator and trying to fix it by adjusting the pressure down with a set of 24's will not work.

 

If you have 24lb injectors, most likely you will be running pig rich. As mentioned, 305's run on 19lbs and the ECM is set up to pulse at that rate. I would check your fuel pressure at the rails, if you are at 42psi at turn key, then you know your fuel pressure is good.

You can either switch to 19lbs or have your ECM programmed to 24lb injectors, both will cost about the same...

 

Thanks. This is just what I thought. I really don't know for positive they are 24's, but they are not OEM and there is a 24 stamped on edge of injector. I beleive there Accel injectors. I just didn't want to change until I did as much due diligence as possible. Gas mileage is also pretty poor. When you have your foot in it, it runs better, but when you want to maintain a steady speed it sputters and misses. There is one interesting twist though. If I jumper ALDL pins A&B the miss goes away, but it's not running at optimal performance. Do you think when you put the ECM in service mode it could change the richness of fuel just enought to elminate the miss? Your thoughts are appreciated because I've replaced most everything to this point.

 

Thanks. Gas mileage is pretty poor. I'm still baffled though than when I jumper ALDL pins A&B the miss goes away, but it's not running at optimal performance of course. Do you think when you put the ECM in service mode it could change the richness of fuel or how the ECM is adjusting engine performance just enought to elminate the miss? If I could answer yes to this I'll just change out injectors and cross my fingers. Any suggestions on a good replacement? GM wants $131/injector!! Outrageous!! Accel 19lbs are about $269.

 

I can't answer the question on jumping pins A&B, maybe it's because it's in open loop vs. closed loop.

As far as injectors, I would go with either FIC(fuelinjectorconnection.com) or southbayfuelinjectors.com, you can get a set of 19lbs for around $130

 

Thanks. I'll give them a shot!