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2000 Blazer

09-23-2007, 04:54 PM
It won't start it trys to turn over but won't start. The problem first started when it was hard to start i would have to try to start it two or three times before it would finally crank over. Now it won't even start at all in help.

09-23-2007, 05:34 PM
The starter is turning the engine over but the engine will not start and run? Is that correct? If so, it sounds like a fuel pressure problem, here is a guideline:

Fuel pressure is not monitored by the On Board Diagnostic (OBD) system. Therefore it cannot set a Diagnostic Trouble Code (DTC), or illuminate the Service Engine Soon (SES) light. For example: If the engine will not run, or stalls, due to insufficient fuel pressure, no DTC’s will be set and the SES light will not come on.

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 sufficient 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.

Here is a link to an adequate, inexpensive, fuel pressure tester:

Post your results and we can continue with the diagnosis.

09-26-2007, 02:47 PM
Obviously do what was suggested but your symptoms sound all too familiar to mine before my fuel pump went which is a common problem with Blazers.

It starts with the fuel gauge bouncing all around for months, then hard starting and then no start or break down while driving. Unfortunately for me I was driving when mine went and it also took one of the fuel injectors with it for a cost of over $1000 to repair. The fuel pump module which also includes the sending unit for the gauge runs about $400-500 to replace.

If you want to do it yourself, you can get a good quality Delphia Fuel Pump Module at the link below for a good price. That's where I got mine and the people there were very good to deal with.

10-01-2007, 08:52 PM
Ok we replace the fuel filter, plugs, wires, cap, and rotor. It ran fine for a day the next day went out to start it and it won't start again.

10-01-2007, 08:56 PM
What is the fuel pressure, and does it hold?

10-01-2007, 09:16 PM
As far as i know it is holding fuel pressure but i will check again in the morning. i am just trying to find out what it might be i plan on spending all day on it tomorrow. last time we checked the pressure it was at 57psi

10-02-2007, 11:58 AM
could it possibly be a vacuum line.

10-02-2007, 12:00 PM
We just replace the fuel pump and i am wondering if it is the pump again

10-02-2007, 12:02 PM
We tryed starter fluid to start it at first it would not fire cause it wasn't tight, the second time it fired right up and now it won't start at all

10-02-2007, 03:13 PM
57psi is too low. Must be a MINIMUM of 60psi. Check pressure as described in post #2 and post your results.

10-03-2007, 12:11 PM
Now it only holds at 40psi and i was told it was the pressure regulater does anybody have any websites as to where the regulator is.

10-03-2007, 01:26 PM
The pressure regulator is part of the fuel injection spider assembly which is located under the upper intake manifold. Here's a link to the post in the "how-to" section which is excellent (and which I followed to replace the spider in my 2000 Blazer with the "updated" spider assembly):

My only suggestion: getting a 16mm wrench on the fuel supply and return lines (one of the first steps in the procedure) is difficult because of firewall interference unless you have a little stubby wrench. I didn't have one, but I cut a cheap wrench in half and it worked like a charm.

10-03-2007, 03:22 PM
I would check it out further, the fuel pressure regulator rarely fails on the CSFI engines. Testing the pressure at the fuel filter will let you know if the problem is in the injector assembly or the tank. Another thing to check is the electrical connector at the fuel pump, they often go bad (especially after a failed pump) and can cause low voltage to the pump, ehich equates to low pressure.

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