Ok i picked up the jimmy and its running into some problems now.
1. Hard starts(takes like 5-6 tires to start)
2. mis-fires at 3-4k rpm
3. will not go past 4k rpm
4. brakes are spongy
i have been reading a little bit and it looks like i need to replace my FPR and do a tune up. i just need someone to confirm this.
brakes i guess i can do a bleed of the system. let me know what you guys think.
97 i think still runs on drum brakes so adjust your rear brake shoes first before bleeding the brake lines. As for your 1,2,3 issues:
The electric fuel pump attaches to the fuel sender assembly inside the fuel tank. The in-tank fuel pump supplies fuel through an in-pipe fuel filter to the SCFI assembly. The fuel pump provides fuel at a pressure above the pressure needed by the fuel injectors. A fuel pressure regulator, attached to the SCFI assembly, keeps the fuel available to the Poppet valves (fuel injectors) at a regulated pressure. Unused fuel is then returns to the fuel tank by a separate fuel return pipe.
When the ignition switch is ON and the fuel pump is running with the engine tunning, the fuel pressure indicated by the fuel pressure gauge at the shredder valve should read 379-427 kPa (55-62 psi) . The spring pressure inside the fuel pressure regulator controls the fuel pressure.
A fuel system that drops more than 34 kPa (5 psi) in 10 minutes has a leak in one or more of the following areas:
1. The fuel pump check valve
2.The fuel pump flex pipe
3.The valve or valve seat within the fuel pressure regulator
A fuel system that drops more than 14 kPa (2 psi) in 10 minute after being relieved to 69 kPa (10 psi) indicates a leaking fuel pump check valve.
Fuel pressure that drops-off during acceleration, cruise, or hard cornering may cause a lean condition. A lean condition can cause a loss of power, surging, or misfire. You can diagnose a lean condition using a scan tool.
When the engine is at idle, the manifold pressure is low. This low pressure is applied to the fuel pressure regulator diaphragm. The low pressure will offset the pressure being applied to the fuel pressure regulator diaphragm by the spring inside the fuel pressure regulator. When this happens, the result is lower fuel pressure. The fuel pressure at idle will vary slightly as the barometric pressure changes, but the fuel pressure at idle should always be less than the fuel pressure noted at 62-65 psi with the engine OFF and ignition key ON.
A rich condition may result from the fuel pressure being above 427 kPa (62 psi) . A rich condition may cause DTC P0132, DTC P0152, DTC P0172 or DTC P0175 to set. Drive-ability conditions associated with rich conditions can include hard starting followed by black smoke and a strong sulfur smell in the exhaust. This test determines if the high fuel pressure is due to a restricted fuel return pipe, or if the high fuel pressure is due to a faulty fuel pressure regulator.
A lean condition may result from the fuel pressure being below 379 kPa (55 psi) . A lean condition may cause DTC P0131, DTC P0151, DTC P0171, or DTC P0174 to set. Drive-ability conditions associated with lean conditions can include hard starting, hesitation, poor drive-ability, lack of power, surging, and misfiring.
Restricting the fuel return pipe with the fuel pipe shut-off adapter causes the fuel pressure to rise above the regulated fuel pressure. Using a scan tool to pressurize the fuel system, the fuel pressure should rise above 427 kPa (62 psi) as the valve on the fuel pipe shut-off adapter connected to the fuel return pipe becomes partially closed. This will test your fuel pump and you can check your fuel pressure rate of drop, if it drops fast. Then you have a leak at your FPR.
Here is another link about converting your SCPI to MFI.
http://www.gmpartsdirect.com/ now has a kit to upgrade from the poppet valve injection to MPI. Kit comes with the spider, bracket and o-ring kit. Part number is PK12568332 (SCPI to MPI upgrade kit) and was $239.90 with shipping.
http://members.shaw.ca/betterthanyoutoo/Sticking Poppet.htm
Good luck and keep us posted.
