My truck has 135K miles and has become hard to start. Engine tries to catch but takes three or more attempts before catches. I have found that you can not touch the accelerator or it may take 10 attempts. When it fires up, idles just like brand new. Doesn't require holding the key very long. It either starts and stays running or starts and dies quickly. The truck also has started surging under hard acceleration above 2500 rpms. Normal acceleration is fine.

Had to get get the fuel pump replaced a month ago when it died away from home. Ran fine after that until recently. Truck has not shown any codes in a long time. No codes now that these problems have shown up.

Some time before that I had to replace the distributor account the rotor cap was wobbling inside the distrib. cap. Probably have put 6k miles on it since the replacement.

Since the new problem started I have replaced distrib. cap, rotor, fuel filter, plugs and wires. This improved performance but had no effect on starting and acceleration issues.

Checked the fuel pressure and found to be at desired pressures. Any ideas which way to go next.

 

Your engine requires 60+psi to start and it should not leak down more than 5psi when the key is shut off.

 

Well, let me start off by saying I have a 4.3LSFI. Figured that out when I didn’t see the word VORTEX on my manifold. Anyway, not getting any ideas. So the more I drive my wife’s truck, the more I figure it has to be a fuel delivery problem. Since I have no problems with fuel pressure, the only way I can go is inside the intake plenum and look for anything obvious. I’ve tried the fuel additive to clean injector/poppet with no effect. Heck the truck runs good except for acceleration over 2500rpm and starting.

 

Just to let anyone know who is interested, Spent the money and bought the injector conversion kit. Cleared all my problems. Starts like it should and surge problem is gone. Other than the expense, rate this as a 4 on the complexity scale, Just pulled the plenum and installed the parts. Only problem I had was a leak in the fuel supply rail. Had to work through getting a good connection. Found that that you need to make rail connections before you seat the pipes to the metering valve.

Also you do not need 60psi. Standard calls for min of 52psi. I get 52psi on first key and runs up to 60psi when running. When accelerate jumps to 65psi and steady's back at 55psi. Starts fine at 52 psi. I do not think I had a bad fuel regulator as I have the same fuel pressure readings as before. Got to believe that Government Motors has been covering labor costs for too long. The conversion kit feels like better perfomance. Will have to wait and see if fuel mileage is better.......

 

Gauge accuracy/calibration differences? The FPR's are calibrated to 58-62psi with zero vacuum.

The MFI spider is a much nicer unit although it cannot flow as much as the SCFI spider that it replaced. It should suit you well though unless you plan on a turbo or supercharger with increased fuel needs....