Jump to content

Slow and Sluggish Start 2015 Silverado 2500HD

SilveradoNewbie
 Share

Recommended Posts

SilveradoNewbie New Member

SilveradoNewbie

Posted
Posted (edited)

Hoping to get some help. The dealership has been no help. About two months ago my gas 2015 2500HD started to start kind of sluggish. Overtime it would crank longer and longer when cold. Got to the point where it was taking 5+ seconds to fire up. Went to the dealership and after $110.00 they told me my throttle body plate was loose. They guy insisted if I didn't fix it ASAP it could break off and ruin my engine. After taking it home I removed the throttle body, which was indeed loose, cleaned, tightened and put it back on. I did notice as I shook the plate there was zero carbon build up where it used to sit on that middle rod. I used that as a guide when tightening it back up. Obviously that didn't fix the problem. I'm not even 100% sure it was loose before I went to the dealership but there is more to that story. I'm still in the same place with the long cranks, however about a week ago I did find a solution to alleviate the problem. I noticed if I turned the key on then back off a couple times before I start the engine it fires up right away every time. Does anyone know what could cause this? Thanks

Edited by SilveradoNewbie
CamGTP Senior Enthusiast

CamGTP

Posted
Posted (edited)

When you turn the key on and off like that, you are running the fuel pump through it's prime cycle. The more you do it the better your fuel pressure is likely getting.

 

Hook up a fuel pressure gauge to the fuel rail, the first prime of the system should already get you above 50psi and it should stay there without bleeding back to nothing right away. If you hook it up, prime it and only get 20-30psi that is an issue. Then after say 2-3 primes it reaches 50+ psi, I'd say you've found part of your issue.

 

I would do this test first as it's cheap or free if you own  a fuel pressure tester.

Edited by CamGTP
TRKLGND Enthusiast

TRKLGND

Posted
Posted

Are you using E85?  That can cause extended cranking times when cold. It did on my 2017 2500HD 6.0L.

SilveradoNewbie New Member

SilveradoNewbie

Posted
  • Author
Posted
2 hours ago, paracutin said:

Are you using E85?  That can cause extended cranking times when cold. It did on my 2017 2500HD 6.0L.

I'm not using E85. I was actually going to try it but it didn't make a lot of sense economically. How did it go for you?

 

3 hours ago, CamGTP said:

When you turn the key on and off like that, you are running the fuel pump through it's prime cycle. The more you do it the better your fuel pressure is likely getting.

 

Hook up a fuel pressure gauge to the fuel rail, the first prime of the system should already get you above 50psi and it should stay there without bleeding back to nothing right away. If you hook it up, prime it and only get 20-30psi that is an issue. Then after say 2-3 primes it reaches 50+ psi, I'd say you've found part of your issue.

 

I would do this test first as it's cheap or free if you own  a fuel pressure tester.

Thanks! I actually have a fuel pressure tester so I'll try that throughout tomorrow when I start up. I'll let you know how it goes. 

TRKLGND Enthusiast

TRKLGND

Posted
Posted (edited)
13 hours ago, SilveradoNewbie said:

I'm not using E85. I was actually going to try it but it didn't make a lot of sense economically. How did it go for you?

 

I'm in central Illinois.  For me, the price difference between E10 and E85 had to be about .60/gal for it to be cost effective.  Even then, running E85 means more frequent fill-ups and my time is worth something.  I did not notice any more power (the power difference in my 1500 with the 5.3 was noticeable) but the idle was smoother.  The truck just seemed to run better.  For that reason I ended up using it even when it was not really cost effective.  It actually ran better on E85 than 91 or 93 octane.

Edited by paracutin
  • 1 year later...
brewguy101 Enthusiast

brewguy101

Posted
Posted
On 10/9/2019 at 3:45 PM, SilveradoNewbie said:

Hoping to get some help. The dealership has been no help. About two months ago my gas 2015 2500HD started to start kind of sluggish. Overtime it would crank longer and longer when cold. Got to the point where it was taking 5+ seconds to fire up. Went to the dealership and after $110.00 they told me my throttle body plate was loose. They guy insisted if I didn't fix it ASAP it could break off and ruin my engine. After taking it home I removed the throttle body, which was indeed loose, cleaned, tightened and put it back on. I did notice as I shook the plate there was zero carbon build up where it used to sit on that middle rod. I used that as a guide when tightening it back up. Obviously that didn't fix the problem. I'm not even 100% sure it was loose before I went to the dealership but there is more to that story. I'm still in the same place with the long cranks, however about a week ago I did find a solution to alleviate the problem. I noticed if I turned the key on then back off a couple times before I start the engine it fires up right away every time. Does anyone know what could cause this? Thanks

Did you ever find the cause of this problem?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • Atlas
      The Peckish Synapse

      By Atlas · Posted

      One of the few things I enjoyed about my time in the midwest was taking off on weekend drives. Unlike home, where we are boxed in by mountains and water, those rules don't apply to the inland plains. Roads connect and sprawl everywhere. While Minnesota is flat, it's not completely featureless and there are fast moving rural roads with curves and slight elevation changes. I used to relish heading out in a particular direction with no set destination, no curfew, and weaving through little townships, wherever the roads would take me. Along farms, lakes, or through the deciduous trees... It was beautiful in its own way, and the seasons were so distinct there. Fall drives yielded amazing shows of color and contrast. Summer drives rewarded with the and amber evening glow of the prairie (and lots of juicy bugs).    I do a lot of that here in my home state too. But it's much less mysterious/intriguing. I've traveled most roads in the region, and every road that's fun to drive within a good radius of my house. But every drive, even on the same old roads, is still enjoyable. I know where I can lean hard into the throttle or really throw the car into a curve. There are exercise loops for when I just need to keep certain cars limber, and much longer routes to settle in and enjoy a drive and put some miles on. All the mountains and water make for some really awesome roads for spirited driving. But not all my driving is spirited, for example, that's not really enjoyable in my pickup or this Blazer (that's still here...).   Sometimes a good drive is followed by a ritualistic wash before tucking the car away...
    • C/K Man
      L8S For 2027

      By C/K Man · Posted

      'GMAuthority' is reporting the 2027 HD's will have the L8S 6.6L gasoline V-8.  There was some talk here about the L8S awhile back.  Not sure what changes it will have now as it seems the 2027 emissions regulations have changed from what was originally proposed.  The big question will be is L8S just a stopgap for the last 2 years of the current T1 HD platform or will it carry forward to the next generation 2029 T1-2 HD's?    I assume the L8S will still be a Gen. V engine. 
    • bruceb58
      New Duramax rumor?

      By bruceb58 · Posted

      New engines will still be using DEF. You just won't have the limp modes occurring when you run out of DEF now.
    • bruceb58
      first oil change - 2026 2500HD gas

      By bruceb58 · Posted

      I am not a NOCO fan for a charger I would leave on a battery 24/7. The reason is, it doesn't really float. It waits until the battery drops to a certain voltage and then charges it back up to 14V. It's better than no charger I guess.
    • bruceb58
      first oil change - 2026 2500HD gas

      By bruceb58 · Posted

      I would never do anything but lithium.   If the vehicle is stored, just turn the disconnect off. My batteries are completely disconnected form everything in the trailer when my disconnect is off. Trailers don't always come that way as some still keep the CO/LPG monitor on. When mine is off...it is off.   As far as storage temps, LiFePO4 are good down to -20°C. I would store them in a heated place if it goes below that. You can also get heating mats with a thermostat if power is available.   The way the heaters work, if it's below 0°C, if a charge comes in, it is directed entirely to the heater until the battery gets above 0°C and then it allows the charge to go to the battery.   For my Android tablet I use as a display, I can move it inside my house if I was ever in an area that got super cold.  

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...