I have a 93 Vortec motor that has a few issues I cannot figure out. First it will not start when the engine is cold with out some type of assistance. Secondally until the motor warms up it has a small hesitation to it, the common sensors have been changed, TPS, MAP, and a couple others, but could really use some help.
The fuel system on this engine has the Centrally Mounted Fuel Injection system. This means there’s a central fuel injector located under the intake manifold that feeds fuel along tubes to each cylinder. At the end of each of these tubes are what are called poppet valves. These poppet valves are forced open through the fuel pressure. So it requires a high fuel pressure to blow open these poppet valves. Something along the line of 63 PSI. If the fuel pump pressure is low, it doesn’t force open the poppet valves enough to allow a rich fuel mixture during a cold start. So the first thing that should checked is the fuel pressure. Because low fuel pressure on this fuel system can have drastic effects on how the engine starts and runs.
Tester
yes I have done that even changed the pump itsself I have 55 to 65 psi when i turn the key to the on position. If I give the air cleaner a quick shot of ether it starts right up.
Did not want to hear that:(
You just might need a new spider assembly. That’s what this fuel injection system is called in tech lingo. And here’s what it looks like. http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c1528003d9a4
Tester
Tester,
That url was a dud. Is this fuel rail what you meant to show? http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c1528008f22c
Your getting good advice but I wonder was the Vortec available in 93? I thought it was a little later like 95,just trival pursuit.
When was the last tune up? You know, plugs, wires, etc… You may also want the coil packs looked at too. I had a 90 something 4.3 Vortec S-10 that did the same to me and it was solved by a coil pack change. Bad news is that they can get pricey…