Hard starting when engine is warm only.

70

Asked by Dec 30, 2014 at 09:46 AM about the 2003 Chevrolet Silverado 2500HD 4 Dr LS Extended Cab SB HD

Question type: Maintenance & Repair

2003 Chey. When engine is cold engine starts and runs just great. Only when engine is
has been running and I leave it off for about 5 to 10 minutes does it have a hard time
starting. After starting it runs a little rough but then it runs fine. When I shut it off I can
smell unburned fuel/hydrocarbons.

5 Answers

85

I would check your fuel pump to begin prognosis, be sure it is fully priming the fuel line and does not make any unusual sounds. Next listen how your flywheel on your starter spins as you turn the key to start your engine (is there hesitancy, grinding, etc?). From your description you mentioned starting, rough running once started, and smell of unburned fuel, after the engine has been warmed up; which is the identifying factor here. Valves are an important part in the distribution of fuel into the engine block, after the engine warms there maybe some blockage or expansion from heat. Be sure to check your distributor cap and other electrical connections, sometimes the slightest electrical sensor misread tells the vehicle it's not working correctly when it really is. I hope this helps or at least gets you started in the right direction

1 people found this helpful.
35,175

Try cleaning the MAF and O2 sensors. It seems like it's a flooded condition, when starting after a brief shutdown. Like the injector driver from the computer is holding the injectors open. The PCM can't tell if the engine is hot or cold. Cleaning the throttle body may help, as well as air and coolant temp sensors too.

4 people found this helpful.
70

What fixed the problem was replacing the fuel presure regulator.

7 people found this helpful.

You must check the alternator under full load as well as check the ground wire both where it connects to the battery and the transmission. Also check the coolant level. If it is alright then you must visit car service station. https://www.yourmechanic.com/cars/chevrolet

2000 k2500 7.4 L 454 . Starts hard after sitting.Starts great on fresh start. Starts great on having recent start. Put my scanner on it and fuel pressure gauge.Everything fine.No codes. One day while driving it quits running and needs a tow.I figured fuel pressure regulator and was right.It runs fine.Still starts the same. Put it back on scanner. Checked crank sensor and cam sensor because I got a crossfire code.Pulled out old crank sensor .It was carbon ed up,cleaned it. put in new Oriely auto parts one, No signal ,junk right out of box.I put old one back in its fine.Checked timing, distributor off maybe due to installing new cap. Runs fine ,same issue.Found out that its the temp.sensor in the block, no code,just not working right.What a pain it also controls fuel and air through the ECM.All these modern computerized vehicles are junk and I am sick of them.If you don't have the tools it will cost a arm and leg to get fixed. I'm going retro 1970's and back.

Your Answer

Silverado 2500HD

Looking for a Used Silverado 2500HD in your area?

CarGurus has 29,859 nationwide Silverado 2500HD listings starting at $2,500.

ZIP:

Chevrolet Silverado 2500HD Experts

  • #1
    Steven Loeffler
    Reputation
    540
  • #2
    Tom Demyan
    Reputation
    370
  • #3
    Matthew Wagner
    Reputation
    330
View All

Related Models For Sale

Used GMC Sierra 2500HD
142 Great Deals out of 15,260 listings starting at $3,500
Used Ford F-250 Super Duty
374 Great Deals out of 42,218 listings starting at $1,600
Used Chevrolet Silverado 1500
1,781 Great Deals out of 149,286 listings starting at $1,495
Used Dodge Ram 2500
147 Great Deals out of 4,934 listings starting at $2,495
Used GMC Sierra 1500
722 Great Deals out of 58,462 listings starting at $1,900
Used Ford F-350 Super Duty
431 Great Deals out of 24,311 listings starting at $3,900
Used Ford F-150
2,344 Great Deals out of 215,477 listings starting at $1,300
Used Chevrolet Silverado 2500
3 Great Deals out of 212 listings starting at $4,495
Used Toyota Tundra
478 Great Deals out of 38,526 listings starting at $1,999
Used Chevrolet Silverado 1500HD
6 Great Deals out of 233 listings starting at $2,650

Used Cars For Sale

2018 Chevrolet Silverado 2500HD For Sale
16,745 listings starting at $25,539
2017 Chevrolet Silverado 2500HD For Sale
35 Great Deals out of 1,748 listings starting at $26,869
2016 Chevrolet Silverado 2500HD For Sale
66 Great Deals out of 1,704 listings starting at $25,900
2015 Chevrolet Silverado 2500HD For Sale
64 Great Deals out of 2,280 listings starting at $13,995
2014 Chevrolet Silverado 2500HD For Sale
8 Great Deals out of 616 listings starting at $9,950

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.