If anyone can help me on this issue I would really appreciate it. I just purchased a 1992 for $600.00 its in pretty good shape, but the people I bought it from said that it will only go 15miles an hour. I looked and there is no catalyac converter on it so that can't be the issue. It is a W motor and it runs but no speed at all. The gas tank has been changed new fuel pump, new plugs and wires and even a different brain, still only 15 miles per hour. I know very little about the Vortec engine that is in it, so any information will be very helpful. Thanks Charlie

 

check fuel pressure with a gauge. (dont eye it,these things are sensitive)

MUST be 60 psi+ at key on and stay above 55 for 10 min...

they are common for fuel issues.

 

Thanks Chris, where do I d ths test at? Never messed with this engine?

 

look behind the manifold (big white thing) on top of the engine. back right side. you'll see a black screw on cap. there is a "nipple" there to test fuel pressure. Go to autozone etc and they have a loan a tool program. its basically a free tool thing. you do have a to leave a 100% refundable deposit (of retail value of the item) incase you dont return it. Once you have it,check the pressure. hook the gauge up. turn the key on. look at the gauge. It HAS to hit at least 60 psi at key on. If it does cool. let it sit for 10 min or so. if it drops below 55ish you have either a bad spider,or a bad valve in the pump. If it holds good,the fuel system is fine. that is if it pings above 60.

Once fuel system passes,move onto ignition. is the service engine light on?

 

Update truck runs but real rough, and there is fuel in the oil, not sure how long it has been like this. Going to change the oil an filter. Could the fuel injection system be dumping fuel into the oil? Bad injector system?

 

No engine service light on.

 

Fuel in the oil usually is an indication of the spider assembly or fuel pressure regulator leaking. Looks like you will be taking the intake plenum off and checking for fuel washing on the intake.

 

Thanks for the input, thats what I figured I would have to do.

 

One more test that I would suggest out of experience is the so-called "nut kit." Inside the intake manifold there are two fuel lines going to the spider injector. They come from threaded fittings on the back of the manifold. When you take the top of the manifold off and expose the injectors turn the key on to energize the fuel pump and check to see if the two fuel lines in the manifold are leaking. That's a common source of leaks in these engines along with the nozzles and fuel pressure regulator.