After 5 years of instantaneous starting, my Yukon recently started taking several seconds (3-5) of cranking before it would start. This is only an issue after a few hours of non use. I replaced the filter and pressure regulator with no improvement. A mechanic tested the pressure which was in normal limits. I've run a tankful of Lucas fuel conditioner/cleaner, but I've seen no improvement. A slight tap of the pedal during cranking seems to help a little.
Specs: '03, 5.3 litre, flex fuel, Z vin code
I would REALLY appreciate any advice you can give. Karl
An expert who has achieved level 3 by getting 1000 points
An expert that got 10 achievements.
An expert that got 5 achievements.
An expert whose answer got voted for 100 times.
Re: 2003 yukon cold start problem
Alternator needs tested (scoped ) for any dirty power (spikes)...that simple test will eliminate soo many electrical gremlins i cant stress it enough.....causing bad floating grounds and computer misreads of sensitive sensors without tripping codes ... replace alternator if suspicious and watch your other seemingly unrelated issues disappear :)......i know i know i am using a crystal ball here tonight and going out on a limb about this one .... but humor me and test alternator before investing too much other time and money :) good luck
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
Does fuel pump run ? Remove fuel cap. Have someone crank it for you,you should hear fuel pump running. If not bang on bottom of tank while cranking. If it starts fuel pump will need replacing , if not check for power to pump, if it has power,replace pump. If no power, check relay for operation
Sorry to get your hopes up but I have a similar problem with my 2005 Yukon Denali. How long does the truck stay running before it shuts down? Mine started out with short spurts of the truck shutting down while driving. It slowly progressed to the point where it will only run for about 45 seconds. Originally the truck would sputter the gauges would die and then the truck would die. It slowly progressed to the point where it only runs for 45 seconds and there is no signs before hand. Does any of this happen to your vehicle? I have checked all of my cables and the main ground wires. Along with changing a few of the relays. Nothing has helped. My problem started with an electrical component heating up and quitting. Now it doesn't matter how hot it is in only runs for a couple seconds.
What happens if you bring power directly to the starter solenoid? Will it crank then? You need to try to isolate the problem. If it will crank with direct power, the starter is NOT the issue. Let us know what you find.
You need spark at the right time, fuel pressure at the injectors, and normal compression. Have the spark plugs been changed in the past couple of years ? Have you checked the fuel pressure to see if it is enough ? Have you sprayed carb cleaner into the throttle body to try to make the engine try to start ? Does it sound like it has normal compression when cranking ?