I should be getting my engine in a week or so. Good, because I am running out of other things to do!!! This being the case, can anyone who has done the 2.8 to 3.4 swap tell me what to expect for fuel rail pressure? I have replaced the original 15 lb fuel injectors with 17 lb units, and don't know if this will drop the fuel rail pressure. Do I need to replace the fuel pump with a higher output unit? Thanks in advance...
IIRC, fuel pressure should be same as the 2.8. As long as the fuel pump and pressure regulator are in good working order, you should be fine.
Agree. Stock pressure should be 43.5 PSI at prime with engine not running and around 40 PSI at about 1000 RPM. However, you should not use the stock Fiero or Camaro injectors. You need a pintle style injector that will flow 16.6 lb/hr (rated at 17#) for the horsepower you're making. The stock Rochesters for the 3.4 often give problems because our ECM's have difficulty operating them. A number of us have had excellent results with Bosch EV1 injector Bosch Part # 0280150415, BMW part # 13641730060. This is a 4 hole pintle injector that flows 16.7 lb/hr at our stock fuel pressure and has the correct resistance and duty cycle.
Agree. Stock pressure should be 43.5 PSI at prime with engine not running and around 40 PSI at about 1000 RPM. However, you should not use the stock Fiero or Camaro injectors. You need a pintle style injector that will flow 16.6 lb/hr (rated at 17#) for the horsepower you're making. The stock Rochesters for the 3.4 often give problems because our ECM's have difficulty operating them. A number of us have had excellent results with Bosch EV1 injector Bosch Part # 0280150415, BMW part # 13641730060. This is a 4 hole pintle injector that flows 16.7 lb/hr at our stock fuel pressure and has the correct resistance and duty cycle.
Thanks for the information. It is more than I expected and great. I ordered the Accel 17# injectors from the Fiero Store. Should I give up on these and get the Bosch? I hope I didn't spend 400 bucks on something that I shouldn't have. I thought that since the Fiero store sold them, they might be ok.
I don't have any experience with Accel injectors so I can't comment on them. The only injectors I've used in 3.4's are the Mustang 302 which are 19#. Too Rich. The stock 3.4 Rochester injectors are 17# but they are disk type and they were worse than the Mustang injectors. Our stock ECM's usually have problems managing them.
I wanted to keep everything stock and not have to go to an adjustable fuel pressure regulator or custom chip so I got a set of Bosch from Fuel Injector Connection in Cumming, Ga. based upon their recommendation. They were just slightly lean but never gave me any problems. The EV1 injectors I list are an upgrade of the injectors I got from FIC. They flow slightly more and have 4 pintle holes for better atomization of the fuel. They can be had off eBay Motors for between $80 and $150 for 6. If the Accel are 17# pinrle injectors with a 90 Ohm impedence, you should be good.
One of our club members who isn't registered here saw our posts. He is running the 7730 conversion instead of a stock Fiero ECM but he's running stock fuel pressure. There have been mixed reviews of the Accel injectors and the Rochester injectors when running the stock ECM. This is what he had to say.
"TFS' Accel injectors work, but not well. I tried 2 sets. Ultimately, since my ECU will handle them, I changed to the stock 3.4 injectors, and the engine ran better. Better idle, better tip-in, and better 0-60.
With the Accel injectors, it always sounded as if the engine was misfiring, and it was running rich."
One of our club members who isn't registered here saw our posts. He is running the 7730 conversion instead of a stock Fiero ECM but he's running stock fuel pressure. There have been mixed reviews of the Accel injectors and the Rochester injectors when running the stock ECM. This is what he had to say.
"TFS' Accel injectors work, but not well. I tried 2 sets. Ultimately, since my ECU will handle them, I changed to the stock 3.4 injectors, and the engine ran better. Better idle, better tip-in, and better 0-60.
With the Accel injectors, it always sounded as if the engine was misfiring, and it was running rich."
Thanks for the great information. I guess it will be a wait and see situation. If I have issues, it appears that I will know right off. Just for a point of clarification, is he saying that his stock '88 Fiero ECM will run the 3.4 injectors? If this is the case, maybe I should have done this to begin with. Makes more sense to me...
No, he isn't running the stock Fiero ECM. He has done the Digital EGR upgrade which requires a later 1227730 ECM that can handle the Multec Rochester injectors that came in the Camaaro and Firebird 3.4 engine.
When we put the Rochesters into my brother's 3.4, it was so rich that it burned your eyes and nose when driving behind him. Stock 86 ECM. Because he was cheap, I reinstalled the stock Fiero 15# injectors. That was short-lived because the used engine turned out to be scrap and a 2.8 was put back into it.
