2001 blazer will not start on it's own but will run if fuel poured down throttle body

[jewelllls]

I have a 2001 blazer 160,000k and have just had the fuel pump replaced(not cheap). The truck would not start prior to this. May not have been the fuel pump?Hmmm. Anyway, if you pour say a quarter cup of fuel down the throttle body, it will start, and run and run and keep on running, yet it will not start on it's own. Any ideas out there, if I left anything out I apologize..

[blazes9395]

Welcome to AF, jewells.

How old is your battery, and has it been checked for a full charge recently? Sounds like the battery is weak. The battery voltage must be around(or a little higher)about 12.4, or 12.6 volts or a little higher.

If the battery is too low, the fuel pump will not prime the fuel system to the right pressure, and, in turn, fuel will not spary out the injectors to the cylinders as required, and a no start occurs.

You stated you changed the fuel pump recently, this may temporarly solve your problem because the pump is new and will have little resistance when the key is turned on. With a weak battery it will work for awhile until the new fuel pump gets broken in alittle, and then same problem again.

Either way, check your battery, and make sure your charging system is working properly too, as a weak charge will slowly, yet gradually discharge the system again.

[alblogg]

After you check your battery you might need to check you connections at your pump. Are you getting power there, did you replace the wiring harness when you replaced the pump?

[blazes9395]

Originally Posted by alblogg

After you check your battery you might need to check you connections at your pump. Are you getting power there, did you replace the wiring harness when you replaced the pump?

I agree, defiently a possibility, common too.

[muddog321]

So, that was before the replcement or after? Lost me.
Starting pressure (test at the port on the fuel rail and tester from Actron is $35) is 60psi min (key on engine off) and then running 53psi or higher.

[sreve]

try cycling the key on to off about 3 times before you try to start it. if this works fuel pressure is bleeding off to zero. confirm with fuel pressure guage.

[rhandwor]

Pull the vacuum line to the fuel pressure regulator and check for gas if leaking replace. Otherwise check it with a pressure gage. If you pinch off the return line at a rubber hose will it start if so replace regulator.

[dlo250]

I had the same problem. Car would crank and crank and not start. Had 60 PSI of pressure on the fuel rail, so I ruled that out. OOPS. After replacing a few electrical items, I found out GM has a known problem with the CSPI fuel injection system. There is a TSB that tells how to clean the injectors, but I went for the permanent fix, and installed the MFI injector spider. The conversion to MFI was no big deal, the parts look the same, but the way the part works is different. The information is here: http://members.shaw.ca/betterthanyou...g%20Poppet.htm
The first part shows the dealer procedure, the second part tells how to change to the MFI system. I had to take off the black intake manifold and the throttle body, but the gaskets are reusable. The "spider" sits inside the black intake manifold. The part looks like this: http://www.autozone.com/autozone/par...3_151679_5560_ Took me about 2 hours to do. Make sure you get some intake/carb cleaner and spray the heck out of everything while you are in. Started the car back up and it ran like a shaved ape. Before I actually thought the transmission was slipping it was so bad. Moral of the story, even if you have 60 psi on the rail, you still probably don't have fuel because this design from GM sucks. Hope this helps somebody. Dave