SCPI Conversion to Multiport Fuel Injection

[yamaha4556]

I have a 98 GMC 1500 with a 305. I’m losing fuel pressure in one of the poppet valves in the OE spider system. After cleaning the whole injection system I’m thinking about just converting the SCPI system to MFI. A couple companies out there make direct fit MFI (problem solver) kits that should be a direct swap. Has anyone every done one of these, and if so how well did it fit.

[old_master]

How did you determine that an injector is leaking? How did you eliminate the possibility of the fuel pump leaking? What is the fuel pressure with the engine off and the fuel pump running, (prime pressure)? Does prime pressure remain above 55psi for 3 to 5 minutes after the pump shuts off? If leakdown is excessive, there is a diagnostic procedure that will tell you if the leak is in the plenum or in the fuel pump.

Here's a link to the conversion from CSFI to CMFI. Keep in mind that the conversion is NOT a "cure-all" fix. The older CMFI system has its own set of problems too.

http://members.shaw.ca/betterthanyou...g%20Poppet.htm

[yamaha4556]

Ive had a rough idle when i start my truck for 4 months now, then it runs fine. First thing i did was a complete tune-up plugs, wires, pcv, fuel filter, cap, rotor, new tps sensor (threw a code). After the tune up i checked fuel pressure and it was normal, cant remember wut it was at. When i turn the ignition on and prime the pump (which a 1.5 years old) there is no difference to the rough start. There are no codes and everything checks out ok. I dont know if the injector is "leaking" but it seem like something on the engine side of the pressure reg is messing up.

Thanks for that link ill try cleaning the poppets to see if it helps.

[old_master]

Checking fuel pressure and leakdown takes 5 minutes and will tell you immediately if there's a problem.

[yamaha4556]

ill do that this weekend. thanks for the tips