My truck will turn over, appears to be getting fuel and spark but will not start. It began to run very rough from a stop when I attempted to accelaerate. That problem did not last long before it just would not start. A computer code reader indicates no problem codes. The service engine soon light is on. Any ideas how I can get it started?
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Re: GMC Sierra won't start
Well if your service engine light is on I guarantee you will have a code ready to be retrieved!!! are you using a OBD 2 scan tool also are you hooking it up correctly?? and you do have a miss fire but you don't want to be GUE$$ING 1 of ten possibles.if your scanner is not working take it to someone whom has a functioning scanner good luck.
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This is not unusual on a diesel. What happens is there is air in the system. If this vehicle has an electric fuel pump loosen line where fuel enters injection pump then turn ignition key to the on position and watch for fuel to appear and then quickly tighten line before turning off key. Then try to start. If does not have electric fuel pump will need a second person. One will loosen line and watch while other cranks vehicle until you get fuel and tighten line before the other person releases ignition switch unless vehicle starts first. If that doesn't do the job do this where line hooks onto each injector. Probably will not have to do this to all injectors but could run rough until all the air gets out of everything. I have farmed with diesel tractor for 25 years and dad I drove the gm vehicles with the 5.7. You normally don't start a diesel without bleeding the air out of the lines although some will self bleed most won't. Hope this does the trick.
The first thing I would check is fuel pressure. This type of fuel injection requires a minimum fuel pressure in order to operate. If fuel pressure is as little as one psi below minimum the vehicle will not start.
You can try squirting a couple of shots of carb spray into the air snorkel while somebody cranks the engine over. If the engine starts and then dies you now you fpdeffinetely have a fuel issue.
If the engine still won't start check for spark.
Let me know what you find.
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If you are at or near the 100,000 mile mark then your fuel pump may have failed. If you remove the fuel filler cap and listen carefully at the filler neck while someone turns the ignition key to "run" [don't actually crank the engine] you should be able to hear the fuel pump buzz for about a second and a half as the key is turned On. If you don't hear the pump buzz then odds are your pump is dead. Your pump may have actually failed making it appear as though you ran out of fuel. Not to uncommon. Hope this helps and good luck!
Find the mass air flow sensor and unplug it and see if that helps any you can do the same thing with the temp sensor and map sonsor one at a time I have seen these not give a code and be bad check the spark plugs and see if they look good
ROUGH IDLING CAN BE CAUSE BY MANY THINGS.I AM LOOKING AT LEAKING VACUUM HOSES OR INTAKE MANIFOLD GASKET LEAK.DIRTY FUEL INJECTORS AND WORN ENGINE VALVES WILL CAUSE ROUGH IDLING.ALSO LOW IDLE SPEED CAUSE ENGINE TO RUN ROUGH.