Blazer turns over but wont start

[702Cougar99]

I have a 95 blazer, with the 4.3 6 cylinder, and it cranks over but wont start, i shot a little starting fluid in it, then it started for a second from the starting fluid, i just changed the fuel filter but that didnt work, it also has a check gauges light on, and the fuel gauge, is reading way passed full, even tho the tanks only about half full, andy ideas on what else it might be? thank you very much

[Chris Stewart]

You might check the fuel pressure.

[DelCoch]

Check out your Fuel Pump by doing the following.

1) Check that you have at least 1/4 tank of gas.

Under the hood, on the driver's side fender towards the firewall, there should be a red fuel pump test wire, it should be hanging down by the electrical junction box. It won't be connected to anything, just hanging there with a gray or black plastic insulator on the end of it.

2) With a fused 12 volt jumper wire, apply 12V to the red fuel pump test wire while checking the fuel pump pressure at the schrader valve with a fuel pressure gauge. (Fuel pressure gauge is about 35 bucks if you need to buy one) If you have less than 50 PSI goto step (4) below.

3) If you do have at least 61 PSI of pressure, (which is needed for the engine to start) disconnect the 12V jumper wire and test the fuel pump pressure at the schrader valve with just the ignition key on, (engine off). Be aware the fuel pump only runs for 2 seconds when you turn the key on (engine off). Then the key has to be off for 10 sec before the pump will run again.

With a properly working pump, the fuel pump reaches its max pressure during that 2-seconds, which should be something over 61 psi. When the pump shuts off the fuel pressure will immediately fall 5 or 8 psi. (This is normal) It should not fall below 50 PSI.

To see the max pressure put the gauge where you can see it when you turn the key on (engine off) or else get someone else to turn the key or watch the gauge. You need at least 61 PSI to start the engine.

4) If the fuel pressure is low: Check the battery with a load type tester. AutoZone will do it for you. A weak battery will cause a no start, as the fuel pump needs max voltage to get the fuel pressure up to and above 61 psi, which is needed for the engine to start.

5) However, before replacing the pump, disconnect the fuel pump wire connector at the gas tank, apply a fused 12v supply to the red fuel pump test wire and leave it there while checking for current on the 12v feed wire in the wire connector at the gas tank. (On my 95 the 12v feed wire going to the tank is gray and the ground is black) Test the current with a voltmeter, while using the ground wire in the connector for a ground. It should read 12 to 13.5v or something a little more than 12v.

If you don’t have at least 12v on the Gray wire try using a different ground. If you have 12v, make sure the wire connector at the gas tank is making a good connection to the fuel pump wire connector.

If you have 12v+ and the pump still doesn't put out 61+ PSI, the pump is toast and needs replaced. (Make sure the battery has 12V+ when doing this test)

If you need to replace the pump, get a Bosch, Delco or Delphi – in that order. The rest are junk. Here’s a link for a good price on a Delphi fuel pump, but also check out the on-line prices at AutoZone and O’Reilly’s. http://store.getgmparts.com/index.html

If you need to replace the fuel pump, (Click Here) for step by step instructions.