2004 Z71. Cranks but Won't Start. Already Replaced Fuel Pump and Fuel Pressure Regulator.

[kpryor]

I have a 2004 Chevy z71 with about 150,000 miles. About 9 months ago I started experiencing a problem where my truck would intermittentl hesitate on the start up. Sometime it would only be a delay of a few seconds, sometimes it would crank for 30 seconds before turning over. So I replaced the fuel pump. This appeared to solve the problem, but about 4 weeks later started experiencing the same problem intermittently. This led to a replacement of the fuel pressure regulator about 4 months ago. Again, this seemed to fix the problem for a time. I am now experiencing the same issue, however today the truck keeps cranking but won't turn over. What to do next? Replace fuel filters, injector issues, other? Any suggestions would be appreciated. Have not checked fuel pressure yet. Thanks.

 

[bottomline2000]

Provided you have good fuel pressure and I assume the motor is turning over but no spark? If so, check your crank sensor. Passenger side of oil pan. May have to drop the starter to replace since it's directly behind it.

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[rockola1971]

Has it thrown any codes? Crank sensor going intermittent on you would cause engine to stall while driving to so id probably rule that out. You really need to isolate if its a fuel delivery problem OR spark problem. So during an even of cranks but wont start have a spark plug ready to go and have someone yank a spark plug wire and put that spare spark plug in it and hold it by the boot and touch spark plug to a good ground and crank it over. You should see a nice bright blue spark. White or orange is no good and would tell you that there is a problem in your ignition system. If all good there then do a fuel pressure test while Z71 is acting a fool and not starting. (Doesnt do much good to troubleshoot it when its not acting a fool)

 

[Yoslick]

Mine was throwing no codes and did the same thing, ended up being my MAF.

 

[bottomline2000]

Has it thrown any codes? Crank sensor going intermittent on you would cause engine to stall while driving to so id probably rule that out. You really need to isolate if its a fuel delivery problem OR spark problem. So during an even of cranks but wont start have a spark plug ready to go and have someone yank a spark plug wire and put that spare spark plug in it and hold it by the boot and touch spark plug to a good ground and crank it over. You should see a nice bright blue spark. White or orange is no good and would tell you that there is a problem in your ignition system. If all good there then do a fuel pressure test while Z71 is acting a fool and not starting. (Doesnt do much good to troubleshoot it when its not acting a fool)

Crank sensor went out on my GTO. It would run perfectly fine, but was hell to start. Don't rule it out.

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