GM truck help.

[KYsawman]

Hey all,
I have a 2013 2500hd Chevy with the 6.0 and six speed with 156k on odometer . I just drove to Missouri and back and only got 13.8 mpg. Drove the same trip last fall and got 20.8 out and 21.4 back. I noticed a lot of black soot on the bumper above the tailpipe. Dealer said it needs intake gasket job. It runs a little rough when first started in the morning but smooths out, never has any codes in computer. I installed OEM plugs and wires at 100k when I bought the truck. Has anyone had similar problems. And how bad of a job is it to change intake gaskets. I still don’t see how intake gasket leak would not cause a code and kill gas mileage.

 

[S Sidwell]

I've it's got the red seal intake gaskets, they need to be changed over to the new green ones. Red ones were bad about leaking. You can spray carb cleaner around the intake and the motor should pickup some speed. Letting you know that's where the leak is.

Steve, Samsung On5 using Tapatalk

 

[S Sidwell]

You could actually do the job yourself ,being on here you have to be mechanically incline. Should take you maybe an hour or so.

Steve, Samsung On5 using Tapatalk

 

[redline4]

Have any broken exhaust bolts or exhaust leak?
Piss poor fuel could cause the mileage also. Thats been the norm lately.

Have access to a scan tool that can read data?

 

[KYsawman]

I figured I could handle the job, I used to work for a Land Rover- jaguar dealer and figured it has to be easier than those intake jobs. Do you have to drain the coolant? I am currently living in an RV park and can only do limited work on my truck here. I was a little reluctant to give in and take it to the dealer. Thanks for the heads up on the gasket color. I saw there was a service bulletin on the gasket.

 

[KYsawman]

Have any broken exhaust bolts or exhaust leak?
Piss poor fuel could cause the mileage also. Thats been the norm lately.

Have access to a scan tool that can read data?

I just replaced the entire exhaust system last fall. No I don’t have a scanner to watch fuel trim settings while running. I have been fueling up with premium shell or chevron to keep the spark knock down.

 

[S Sidwell]

Try carb cleaner around the intake and see if rpm' s change. No you don't have to drain anything. Leave fuel rail attached to intake, less to remove and no need, just disconnect fuel line. Throttle body can stay on also.

Steve, Samsung On5 using Tapatalk

 

[S Sidwell]

Keep us posted and if you got questions, ask away. Just be glad it isn't on a 2019, hate some of the new connectors on the harnesses and pipes they are using now, PITA. And the freaking harness attached to the back of the intake, give me a break, I'm not in my twenties any more GM. Getting real hard to crawl under the hood now days.

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[KYsawman]

Try carb cleaner around the intake and see if rpm' s change. No you don't have to drain anything. Leave fuel rail attached to intake, less to remove and no need, just disconnect fuel line. Throttle body can stay on also.

Steve, Samsung On5 using Tapatalk

Awesome thanks for the info! I am going to order gaskets tomorrow and try to get it done next weekend.

 

[Dub11]

I just replaced the entire exhaust system last fall. No I don’t have a scanner to watch fuel trim settings while running. I have been fueling up with premium shell or chevron to keep the spark knock down.

If you need a scan tool get one of these.

And the torque lite app from google

It was $30 from Amazon

 

[KYsawman]

If you need a scan tool get one of these.
View attachment 177346
And the torque lite app from google

I will have to check that out, thanks, I miss working at a shop and not having all the scan tools to figure things out.

 

[S Sidwell]

I like my Launch I got a few months ago, covers a lot of brands, U.S., Asian, and European, up to 2018 on some. I do have the GM Tech2 and both GM MDI's.

Steve, Samsung On5 using Tapatalk

 

[Dub11]

I will have to check that out, thanks, I miss working at a shop and not having all the scan tools to figure things out.

Check the app out and see if it will have everything you need before buying it. I like it for the ability to link online and tell you what the code means.

 

[S Sidwell]

Got lucky on my Launch, usually 150 and up, fellow ran a sale for 125 shipped, jumped on that.

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[S Sidwell]

This is what I got.

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[Hinerman]

Hey all,
I have a 2013 2500hd Chevy with the 6.0 and six speed with 156k on odometer . I just drove to Missouri and back and only got 13.8 mpg. Drove the same trip last fall and got 20.8 out and 21.4 back. I noticed a lot of black soot on the bumper above the tailpipe. Dealer said it needs intake gasket job. It runs a little rough when first started in the morning but smooths out, never has any codes in computer. I installed OEM plugs and wires at 100k when I bought the truck. Has anyone had similar problems. And how bad of a job is it to change intake gaskets. I still don’t see how intake gasket leak would not cause a code and kill gas mileage.

21 mpg!!!!!! Are you kidding me? That's amazing.

 

[Bigmac]

I just replaced the entire exhaust system last fall. No I don’t have a scanner to watch fuel trim settings while running. I have been fueling up with premium shell or chevron to keep the spark knock down.

Did you replace the exhaust before or after the first trip? Is it a stock system or higher flow?

 

[KYsawman]

Did you replace the exhaust before or after the first trip? Is it a stock system or higher flow?

I replaced it before, all stock.

 

[Bigmac]

I replaced it before, all stock.

Have you always had ping issues or is it more recent?
If it is an intake leak and throwing a code it would be causing and air leak of non metered air, air not seen by the mass air flow meter and not allowing a proper air fuel ratio, creating a lean condition. This may have been at the edge of the or throwing a code on the first trip and now that it has thrown a code it is in limp mode with a rich air fuel ratio to save the engine, just throwing it out there

 

[KYsawman]

It has always pinged , since I got it at 100k I have never had a code come up, just stumbled at idle when cold and gas mileage gone now. The factory exhaust was damaged by former owner and I replaced with oem. It is puzzling to me that I never see any codes.