I HAVE A 2001 CHEVROLET BLAZER THAT STARTS HARD ON COLD MORNINGS. NO RED LIGHTS OR CODES BEING SHOWN. TUNE UP RECENTLY COMPLETED (PLUGS, WIRES, CAP ROTOR). ONCE STARTED BLAZER RUNS FINE AND STARTS FINE UNTIL SITTING AGAIN FOR SEVERAL HOURS WHEN IT HAS A HARD START AGAIN.

Marvin

• 85242 Answers
• Posted on Jan 16, 2009

SOURCE: hard to start chevy 350 vortec

You will need to do a fuel pump pressure leak-down test, the pump must not loose more than 5 PSI overnight, u will need a cheap fuel pressure test guage, the test port is on the fuel supply rail to the injectors on the intake manifold, it looks like a tire valve but metal with a plastic cap on it, u may be able to borrow this guage from Kragen, Autozone or a parts store like them, if not they are very cheap, less than $20 US. Run the engine with the test guage hooked up, turn off the engine and then check it in an hour or so, if it drops more than 5 PSI then u will need to replace the fuel pump in the gas tank. One note make sure the connection for the guage is tight with no leakage or the test is invalid

SOURCE: 96 gmc sierra hard to crank after 12-14 hours

that has a votec engine in it the fuel pressure is droping at knight and it takes 60 psi before the injectors will fire most likely cause fuel pump ,leaking injector ,or a feul pressure regulator

SOURCE: 2001 Galant service engine light on & won't stay running/ runs rough

Try this: Disconnect the ecm control (where the air filter is housed)
Let me know if that worked.

SOURCE: 1999 chevy silverado 4.3 new

I just replaced the fuel pressure regulator and now I am hearing a vibrating noise from the fuel line under the truck. What do you think the problem is.

Harvey N Tawatao

• 3854 Answers
• Posted on Mar 20, 2010

SOURCE: my 95 blazer 4.3 will not start, it cranks, has

Try replacing the fuel filter, but it sounds like you have a weak fuel pump. Your cold start pressure should be 62-65 psi and drop about 5 psi when the engine is running. Anything less then 62 psi is going to cause you to have starting issues, you can also test your fuel pump by blocking off the return line to see if you get 75-78 PSI. this is just a test to see if your fuel pump is still good. If you have less then that with the return line blocked off, replace your fuel pump but check your ground wire first. The ground wire is separate from the wire harness and grounded to the frame and a bad ground will give you a weak pump.
Thank you for using Fixya and good luck