Mechanics

I HAVE A SPORADIC STARTING PROBLEM, OVER THE PAST 8 WEEKS I HAVE HAD 4 TIMES WHEN THE ENGINE TURNED OVER BUT WONT FIRE.

2007 Hummer H3 • 72,000 miles

I have had 2 mechanics tell me that it is the fuel pump. One mechanic says that the armature on the fuel pump motor has a dead spot and that is usually the problem.... If that is so, then why does it start right up later. Sometimes as quickly as 15 minutes, he then told me that temperature fluctuations can cause the problem. I don't want to spend $400.00 for a fuel pump assembly for a "might be problem". I've changed plugs (new that wasn't the problem, but did it anyway). I also have added a "G-Force" chip to the map or Iat sensor, but unplugged it after the first no start problem. The only other thing I have changed is that I installed a "K & N" air filter. I paid the online mechanic $18.00 for his answer "dead spot on armature".
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R.spoonemore
December 28, 2011.




I agree with the tech that told you about the pump. Common failure in gm's. When it does not start, you should have the fuel pressure checked to verify.
I would put your original air filter back and get rid of the K/N. It contaminates the sensors and voids warranties.

Roy

ASEMaster6371
Dec 28, 2011.
Next time it refuses to start don't wait for it to make up its mind-do below immediately to determine if its fuel or spark problem

Get a helper disconnect a sparkplug wire or 2 and ground it to the engine atleast 3/16 away from ground-have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel related problem, Do you hear the fuel pump come On when you turn key on? If not check fuel pump fuse and fuel pump relay if okay-check the fuel pressure to rule out the fuel filter/fuel pump/pressure regulator and listen to the injector/s are they pulsing or hook up a noid light. No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs, coil's resistances, cap and rotor, distributor pick-up coil, ignition control module, cam and crank sensors and computer Note: If it doesn't apply disregard it and keep testing
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Tiny
Rasmataz
Dec 28, 2011.

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