I HAVE A 2003 GMC SONOMA 4

  • Tiny
  • lasurvivor47
  • 2003 GMC Sonoma
  • 120,000 miles

I have a 2003 Gmc sonoma 4.3. The engine cranks, but won't start. I have a Innova Scan tool and only one code appeared. (P0102). It also read, Mass or volume air flow circuit low input. At the top of the screen, there were little letters flashing. C, EV, O, OH. Thank you for your help! Paul

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Monday, December 31st, 2012 AT 1:50 PM

9 Replies

  • Tiny
  • hmac300
  • Expert
  • 43,623 posts

Check to see if your duct work has holes in it/dirty air filter detiroating filter, blocked exaust. Then check fue pressure should be 60-66 psi

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Monday, December 31st, 2012 AT 2:26 PM
  • Tiny
  • lasurvivor47
  • Member

Thanks for your reply. I did a fuel pressure test the other day and when I was cranking the engine the psi was 60. When I stopped cranking the pressure went to 57 psi and stayed there. I installed a new air filter the other day. Two questions: How do I check for a blocked exhaust? And what do you mean by, "see if duct work has holes in it?" Thanks. Paul

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Monday, December 31st, 2012 AT 2:54 PM
  • Tiny
  • hmac300
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  • 43,623 posts

The duckt wor going from maf to throttle body or any valve cover with a grommet if they have holes it will set it. I am no tfamiliar with the innova tool so have no idead what your letters mean. Fuel pressure seems ok as it needs to hold within 5 pounds after shutdown. Check crank an dcam sensor for resistance they won't set a code sometimes and car won't start. Also make sure to check all your fuses in underhood box. We have no specs for those though

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Monday, December 31st, 2012 AT 4:01 PM
  • Tiny
  • lasurvivor47
  • Member

I appreciate your time helping me. Yes the fuel pressure remained at 57 psi for more than five minutes after I shut the key off. I also checked all the fuses under the hood a little while ago and they we're all good. I will check the other things you mentioned. Forgive me, but how do I check the crank and dcam sensor and where is it on the 4.3? Thanks again. Paul

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Monday, December 31st, 2012 AT 7:01 PM
  • Tiny
  • hmac300
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  • 43,623 posts

The cam sensor is in the dist and the crank sensor is in the timing cover on bottom pass side.

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Monday, December 31st, 2012 AT 8:07 PM
  • Tiny
  • hmac300
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  • 43,623 posts

Ya know just for the heck of it take some choke cleaner and spray down throttle body see if it starts. If it does then it's a fuel problem.

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Monday, December 31st, 2012 AT 8:08 PM
  • Tiny
  • lasurvivor47
  • Member

I found the crank sensor, and I will check the cam sensor. Forgive me, I forgot to tell you I tried fuel down the throttle body a few days ago and it ran until the fuel ran out in the throttle body. So i'm getting 60 psi when cranking and 57 psi with ignition off. Pressure holds at 57 psi for more than 5 min: I'm thinking, if it's holding pressure there's nothing wrong with the fuel pump or filter, and the spider injectors, fuel regulator are not leaking too. What do you think? Thanks you sir! Bye the way, if I don't talk to you this year, I'll talk to you next year! Lol! Happy new year! Paul

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Monday, December 31st, 2012 AT 10:36 PM
  • Tiny
  • hmac300
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If you sprayed fuel and it ran then it's a fuel problem not ignition. Try a fuel filter replacemnet if you haven't already then it wil probably be a fuel pump even though your pressure seems good

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Monday, December 31st, 2012 AT 11:00 PM
  • Tiny
  • lasurvivor47
  • Member

Ok thank you. I will try that. Happy new year!

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Monday, December 31st, 2012 AT 11:12 PM

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