Hard start

Tiny
LUCKYJOHN321
  • MEMBER
  • 2005 GMC YUKON
  • V8
  • AWD
  • AUTOMATIC
  • 169,000 MILES
2005 yukon 6l hard cold start, 5 trys, plugs black, wet on start up, codep0300 random miss, in 30 sec it smooths out runs fine. Fuel press 60 psi new up o2 sensor, new mass flow, new crank sensor, new plugs. Nothing has changed
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Saturday, April 2nd, 2011 AT 5:30 AM

12 Replies

Tiny
RACEFAN966
  • EXPERT
So what is the fuel pressure at start up and what does it do once it smoothes out and runs ok?
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Saturday, April 2nd, 2011 AT 1:54 PM
Tiny
LUCKYJOHN321
  • MEMBER
Turn on key 58psi start 58 step on gas under load 57.5
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Saturday, April 2nd, 2011 AT 11:35 PM
Tiny
RACEFAN966
  • EXPERT
The fuel pressure is a little low. How long has it been sense the fuel filter has been replaced? If more then a year then change it and see what that does. GM's fuel filters should be changed yearly. Let me know how it goes.
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Thursday, April 7th, 2011 AT 2:56 PM
Tiny
LUCKYJOHN321
  • MEMBER
There is no fuel filter on a 05
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Thursday, April 7th, 2011 AT 6:10 PM
Tiny
LUCKYJOHN321
  • MEMBER
Why would low fuel pressure flood an engine on start up
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Monday, April 11th, 2011 AT 3:57 PM
Tiny
RACEFAN966
  • EXPERT
The computer will do what is needed to try to get fuel or it could be that a sensor is telling the computer to do something to change injector pulse or width. However I show a napa part number 3481 for the fuel filter? It is on the inside of the frame about under the drivers seat area. Thats what I show anyway.
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Tuesday, April 19th, 2011 AT 3:28 PM
Tiny
LUCKYJOHN321
  • MEMBER
Sorry there is no fuel filter, try and google it and find out, fuel psi specs are 55-62, im at 58, I dont think you have answered my question, and I dont think you can.
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Wednesday, April 20th, 2011 AT 12:23 AM
Tiny
RACEFAN966
  • EXPERT
Ok it may not have a fuel filter there is a time there where they didn't and the aftermarket shows they did. As for the fuel pressure needs to be about 60-62 at initial start up then runs at around 55 or so. Now if this is only at start up when its cold have you checked the coolant temp sensor? It can be ohmed with a meter. No I can't just give you an answer to your problems I need to ask questions and then try to find answers that make sense. I use Mitchell on Demand to get my info.
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Wednesday, April 20th, 2011 AT 2:26 PM
Tiny
LUCKYJOHN321
  • MEMBER
Coolant temp reads proper on scan tool
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Thursday, April 21st, 2011 AT 4:25 AM
Tiny
RACEFAN966
  • EXPERT
Have you ohmed it though. It may scan ok but may not ohm correctly, the scan tool picks up codes and such depending on the scanner. The coolant sensor can scan ok be out of ohm range the computer thinks it is colder then it really is. So if you would when it is cold ohm it and then get me the ohms with the temp at the time you check it ok. Thanks.
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Sunday, April 24th, 2011 AT 2:29 PM
Tiny
JANARICH0831
  • MEMBER
This is to luckyjohn321 I am having same issue wondering if you ever found problem
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Saturday, August 6th, 2011 AT 6:37 PM
Tiny
RACEFAN966
  • EXPERT
Never had the chance to finish more testing. You must remember doing this over web is not as easy as having it in my shop where I can drive it and check it out in person, it changes how you have to go about it to try and figure out what it going on. It usually take longer to. Sorry I didn't get it figured out quick enough however I did try.
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Monday, August 15th, 2011 AT 3:34 PM

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