GR82BINSPIRED

i have a 2000 blazer that just had fuel pump and filter changed in. Now it runs great starts great but after i have been running it and i turn it off it won't start back up unless i let it sit for awhile.The engine sounds as if it is out of fuel when it is not. Then it starts right up.

old_master

When it's acting up, try squirting some carb cleaner in the air inlet and try to start it. If it starts, the problem is lack of fuel, if not, it's electrical. Post your results.

GR82BINSPIRED

It Starts When I Spray Carb Cleaner In It. Does this mean it is the spider and do i have to replace the whole thing . i got a quote to replace it for $800 which i think is a bit high. i replaced the fuel pump about 2 weeks ago. the car runs great ,good gas milage just when it has been running it wont restart if i turn it off. After it sits a bit it will start right up again,

ricksza

Sounds more like your engine is being flooded, most likely from a leaky fuel pressure regulator. Of course it's located right on the spider injector but it can be replaced separately. Same labor but less for the parts.

old_master

If it starts with carb spray, there is a lack of fuel, not flooding.

Fuel pump operation:
The fuel pump circuits are designed to activate the fuel pump relay continuously any time the key is in the START position. When the key is in the RUN position, the fuel pump relay remains activated provided the Powertrain Control Module (PCM) is receiving a signal from the crankshaft position sensor. If the engine stalls, or is not running for any reason, the PCM will deactivate the fuel pump relay after approximately 2 to 3 seconds. The 2-3 second ON time is commonly referred to as “fuel pump prime”.

Fuel pressure test:
This test checks the pumps ability to build pressure, and the systems ability to hold it. Install the fuel pressure gauge to the test port near the distributor. Turn the key to the RUN position but do not start the engine. While the fuel pump is running, fuel pressure must be 60-66psi. After approximately 2 to 3 seconds, the fuel pump will shut off. Fuel pressure must remain between 55-60psi for several minutes. A drop in pressure below 55psi indicates excessive leak down.

Diagnosing leak down:
External fuel leaks include everything from the pressure line connection at the fuel pump, through the fuel filter, and up to the line going to the injector assembly. Internal fuel leaks can occur at the check valve in the fuel pump assembly, the fuel pressure regulator, the fuel lines under the upper intake manifold, or a fuel injector. Accurate diagnosis for pinpointing the cause of an internal leak, and testing the fuel pumps maximum output pressure requires the use of additional test equipment to isolate each component. In some cases it requires the removal of the upper intake manifold.

Here is a link to an adequate, inexpensive, fuel pressure tester: http://www.harborfreight.com/cpi/cta...emnumber=92699

Post your results.