Jump to content

2017 Duramax L5P base idle

jaws3
 Share

Recommended Posts

jaws3 Enthusiast

jaws3

Posted
Posted (edited)

After the recent recall for Emission System upgrade to comply with gov standards (done 2 weeks ago) the base idle speed has increased to over 800rpm. Used to be just above 500rpm. Dealer says the higher base idle speed is "with limits". I don't agree. Talked to 2 drivers of similar trucks today and both said there base idle speed is just above 500rpm. These are company trucks so they don't know if recall upgrade was performed on the trucks they are driving. The exact scenario is that when I start the engine, idle is normal at just over 500rpm. It stays normal when shifting into DRIVE. Then start driving and at the very first stop 700m from my house, it base idle is over 800rpm. It stays like that until I shut down the engine and it is back to 500rpm when I start the engine again after work. But only until the first stop when it stays above 800rpm. This has been going on for the past 2 weeks (during which I also did a 1200km highway trip). I cannot find a reference to base idle speed on this engine. Is 800rpm considered normal? If it is my "new normal" I'll be selling the truck as it is driving my crazy with the added noise sounding like a jet engine at startup.

Edited by jaws3
spelling
2018GMC Senior Enthusiast

2018GMC

Posted
Posted

Go to a different dealer.
 

Example:

 

We had oil pressure gauge on lml suddenly read 120 psi anytime above idle. 

 

GMC dealer said there was no max spec for oil pressure just minimum. I suggested they change sending unit as everything was fine the first few years. They politely offered me an oil change I’d have to pay for  
 

I complained to GM customer care and setup an appointment with Chevy dealer across town. They replaced sending unit and all was back to normal. 
 

Original dealer must have gotten a call from GM because they called me and offered a free oil change as an apology. 

jaws3 Enthusiast

jaws3

Posted
  • Author
Posted

Good idea but not easy. Next dealer is 200km away from here...

redwngr Senior Enthusiast

redwngr

Posted
Posted (edited)

Aftermarket floor mats? 

 

Position sensor for skinny pedal loose or out of adjustment?

 

I'm not buying dealers 800 rpm soy either.

On the diesel sites lots have reported having the recall done -- no one has reported an increase in idle speed. 

 

 

Edited by redwngr
jaws3 Enthusiast

jaws3

Posted
  • Author
Posted

No aftermarket floormats. Everything as it was prior to the recall except the 800rpm. But thanks for corroborating that it is not normal.

redwngr Senior Enthusiast

redwngr

Posted
Posted

Good point ho

7 hours ago, hollywoodsle said:

image.thumb.png.0081ca072cbe96c063749b5018ad92c8.png

Good point.  

 

They can run high idle at startup, sorta like automatic choke on an old gasser.

And they can run higher for a reason like electical load, coolant temp and so on. 

They also will run higher shift points when cold.

 

My response was interpreting the op's description as never returning to a low idle once fully warmed to normal.  

 

curver900 Enthusiast

curver900

Posted
Posted

It will also run higher idle when Regen is active iirc on mine it is right around 800-900 rpm .  Make sure it completed a Regen.

 

jaws3 Enthusiast

jaws3

Posted
  • Author
Posted (edited)

Yes, idle never returns to baseline. This is not a "variable" idle rpm. It is over 800rpm all the time. Except at start up when it will idle at nase rpm  ut as soon as I drive off and stop the first time, it is above 800rpm and does not ho down until I shut down the engine

Edited by jaws3
Clarification
jaws3 Enthusiast

jaws3

Posted
  • Author
Posted
6 hours ago, white94rx said:

Your truck is in the middle of a regen. Drive it longer and when it's done the idle will go back to normal.

Sent from my Pixel XL using Tapatalk
 

Thank you white94. In my original post I stated this has been going  on for 2 weeks since the software update. It includes daily driving as well as a 1200km weekend trip. Surely that should be far enough? I have also noticed over the past 3 days TV that the gear change occuring just above 50km/h is very rough. As if the truck "jumps" at that changeover. Not sure if it is related but the truck is rapidly becoming very unpleasant to drive. Will make another call to dealer as that seems to be my only ootion. Apart from selling it.

curver900 Enthusiast

curver900

Posted
Posted
On 4/25/2020 at 11:31 AM, white94rx said:

That definitely should have been far enough. Mine usually takes about 20-30 minutes.

Sent from my Pixel XL using Tapatalk
 

Mine does it in exactly 20 miles if kept above 40 mph

jaws3 Enthusiast

jaws3

Posted
  • Author
Posted
1 hour ago, curver900 said:

A call to gm customer service is probably in order or have another dealer or this dealer reflash it

Have an appointment with the dealer next week to look at this again

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
      OCI, not when but why?

      By Atlas · Posted

      On the subject of OLM, Gm's OLM tool may be more "informed" than others brands. I recall OLM's in mid-2000's Chrysler products literally counting down a set number of miles. That's all the OLM appeared to be.    I would actually expect GM to be able to explain the parameters that their OLM takes into account from a high level. No, I would not expect them to disclose their software coding or data analysis around their parameters.   So we're talking about two different topics, so to continue the subject on the other one, I'd be curious to know how much "standard particulate matter" in fresh oil is able to be filtered at first start by a fresh oil filter. How much particulate matter is enough to "matter"?   I.e. how much of a "lever" do we think this equates to (variability in particulate content, in fresh oils, between different makes/brands, some which filter less, and some that filter more).   We can say that more particles = more wear = shorter engine life as a logical statement and use that data with a little marketing to scare people into selecting a more refined/filtered oil. Using a similie, is this like deciding to forego two alcoholic drinks in a lifetime because we're worried about the potential impact on lifespan? Are there numbers which translate the ISO test results into a quantifiable increase in wear for a given engine/use case?
    • chris21
      Brand new to this forum. Questions about re-gearing my 26’ HD

      By chris21 · Posted

      I'm pretty sure it doesn't actually recalibrate the speedometer it just changes the wheel speed sensor inputs to the computer. The truck still thinks it has stock tires.
    • asilverblazer
      OCI, not when but why?

      By asilverblazer · Posted

      I apologize, I missed this post, at risk of going off CURRENT TOPIC.   I'm not saying it is BS, I'm questioning how much information is being held back. GM is NOT going to spell out exactly every parameter in the algorithm. Liability, intellectual property, etc.    I'm not naive enough to believe that it is as simple as revolutions, coolant temperature, miles, time; are you?    I don't do irrational either, and boiling the OLM down to four simple values that I could code in an afternoon (I'm not a coder) is irrational - unless it suits your agenda to ignore it. 
    • BDS my HD
      Brand new to this forum. Questions about re-gearing my 26’ HD

      By BDS my HD · Posted

      Chris 21 I appreciate your constructive response. !!  😉😉😉   The 6.6 is gas.  Correct me if I’m wrong but by recalibrating the speedo you’re correcting the shift points of the transmission on these trucks.?.
    • newdude
      Brand new to this forum. Questions about re-gearing my 26’ HD

      By newdude · Posted

      That is a huge misconception.     Bigger does not always equal safer.  Modifying does not make it safer either, with exceptions.   Think of this.  Your truck in stock form is capable of emergency maneuvers, proper stopping distances, its handling is designed around the factory wheel/tire packages, etc.   37s and a lift?  Now you've affected your braking distances, handling and ride control.  You've raised your center of gravity higher.  Your front visibility is now obstructed more than stock, same for your rear.  Does it look cooler?  Yes.  Does it now work as good as it did from factory on road?  NO.       As for my mention of exceptions?  Say you had a sedan or crossover.  They typically come with all season tires.  If you swap out for a performance all season or a summer tire, you improve your car by lowering its stopping distance (better braking because of traction) and improve the handling (regular and emergency) of the vehicle.  That is an actually improving modification.  My old 2019 LD 1500, I ran UHP all season tires on 20in wheels in a factory offered size.  It improved all aspects of how it drove over the Duratracs it came with from the factory in the stock 18" tire.  

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...