Hello,
I recently picked up a beautiful 98 Tahoe 5.7 4x4 2 door with 150,000 miles for a great price with an engine that ummm needs work. Truck has not run for 18 months, since a fuel fire melted some drivers side components. The cause of the fire; previous owner attempting to purge the fuel from the cylinders with the coil wire still plugged in. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
The symptoms of the original issue are intake is filling with fuel when fuel relay is plugged in and when attempting to start. It cranks really slow for a few seconds (like it has a dead battery, but its at 14 amps) then I think it hydro-locks. After removing all the excess fuel from intake and cylinders, I pulled the fuel relay and it will crank quickly, as it should. The previous owner installed a new fuel pump, fuel filter, fuel relay. I have replaced the half-shaft, inner and outer tie rod ends, upper and lower control arm ball joints and a brake hose, all of which were, well VERY crispy. <o></o>
I have installed a new fuel pressure regulator by the spider unit under the manifold, no change, but I have not checked the fuel pressure yet. I also have not done a compression check or replaced the cap/wires/plugs yet, but hope to do that today. The spider / poppet system was carbon charred thick. I also replaced oil and filter which were mostly fuel. From what I read on a great trilogy/saga thread from bronzebogen/in2pro/DarylH this could be some sort of electrical issue, EGR valve, cam sensor, crank position sensor, or OMG a wrecked main bearing issue. I have “borrowed” the SFI/spider/poppet unit from my ’97 Silverado and going to test today to see if that is what is leaking the fuel. If so I may replace the injectors with, O’ Reilys BWD part number 63886, a newer system without the poppet that, I have read, works better. Any suggestions of parts I can “borrow”, to diagnose?

Thank you for all the great threads I have read over the past few days, learned tons.

 

sounds like you're on the right track. fuel leaking would only be a few things, pressure reg., leaking injectors/poppets, broken feed line from injector to poppet. the mfi conversion is worth it even if the stock unit is ok. if nothing else, for peace of mind. you will need the new bracket, but check the box that the mfi unit comes in as when i did mine, it came with the bracket, even tho it said it didn't. checking fuel pressure is a must as well as a compression check. i found on my 98 motor that my valve stem seals were leaking as well. i had both heads cleaned up and checked for cracks, then reassembled with new seals. motor runs better than new now. good luck, keep us posted.

 

spent the day replacing sfi injector spider with "borrowed unit", and the intake is no longer fill ing up with fuel, and vaper locking.
i then replaced cap and rotor, wires and plugs with new delco. motor will fire and run on starting fluid, but checked fuel pressure and it reads 16 lbs not 60 lbs.
dropped tank and checked pump filter after checking inline filter, both clean. I am looking for a supplier who will just sell the $100 pump without the $100 unit.
i find it interesting the sfi leak issue and the fuel pump would both be bad at the same time. wanted to check the voltage to the pump, but unsure how and what it should read. have to wait till payday to get the new fuel pump, the silverado has a diferent pump so i cant "borrow" it.

 

thank you Maxxman 04, the fuel pump, regulator and swaping the sfi unit out fixed the issue, as well as the other part listed previously. went for a 3 mile drive today,the first drive for the truck in 18 months, so for all the frustrated chevy owner out there, have patience and you will get it.