Exhaust Brake - trouble, VERY FRUSTRATED

[2013 3500 Silver-ado]

I have a 2013 3500 Duramax.

I usually drive with the exhaust brake activated and in tow/haul mode when around town.

For the first 4500 miles, any time I took my foot off of the accelerator, the exhaust brake would aggressively activate and begin slowing the truck even when going down a 9% grade.

I now have 5500 miles on it and for the past 1000 miles the exhaust brake has been significantly less effective and now when I go down the same 9% grade I need to apply the brake pedal to keep the truck from speeding up.

If I set the cruise control to about 50 MPH and then begin pushing the decelerate button for the cruise control, the truck will begin down shifting and for just a second or 2 the exhaust brake will be aggressive again and then just be minimal.

I have had the truck to the dealer 3 times and they tell me that there are no codes and it seems to be working properly.

It drove very different for the first 4500 miles and the dealer can not find anything wrong with it.

The Duramax Diesel book that came with it states on page 9-19,
".....The system delivers the correct amount of braking to assist in vehicle control. The heavier the vehicle load, the more active the exhaust brake will help maintain vehicle control......"
"......This can vary based on vehicle speed, gear, and load. ..."

What data exactly does the truck use to determine the correct amount of exhaust braking?


I put 6 turns into the torsion bars to level it a little bit, Does the truck have any kind of level indicator that could throw off the exhaust brake?

I also dropped the rear tire pressure to about 60 PSI since I don't haul a lot and wanted to smooth out the ride a little bit, Could the slight pressure reduction throw something off?

The dealer had checked the vein position soleniod and sensor and told me both are working correctly and there are no codes found.

I WANT THAT AGGRESSIVE EXHAUST BRAKE BACK !

Any help would be appreciated

 

[dmaxfireman]

For some background, I am the guy that is trying to fix this, and it is a legit situation. When logging the vane position when decelerating the actual vane position is anywhere from 10-15% lower than the commanded vane position. BUT there are no codes to be found anywhere. I am going to get some more logs on Tuesday that I will post up and hopefully we can get this figured.

Has anyone else experienced this on an LML??

 

[DIESELMAFIAPER.LB7]

I haven't had a lml with this problem yet is the truck stone stock?

 

[2013 3500 Silver-ado]

I haven't had a lml with this problem yet is the truck stone stock?

Truck has 6 turns on the torsion bars and I dropped the rear tire pressure to about 60 PSI.

Other than that it is completely stock.

 

[dmaxfireman]

Any thoughts? Thinking there might be some play between the solenoid and the vanes

 

[gassux]

Had an issue with pacbrakes years ago, needed to be lubed regularly with their specific stuff. We tried wd40 but it made it worse. What brand brake is on there?

 

[2013 3500 Silver-ado]

Had an issue with pacbrakes years ago, needed to be lubed regularly with their specific stuff. We tried wd40 but it made it worse. What brand brake is on there?

That is the factory turbo with exhaust brake.

 

[chevyburnout1]

Had an issue with pacbrakes years ago, needed to be lubed regularly with their specific stuff. We tried wd40 but it made it worse. What brand brake is on there?

This is the factory turbo brake, not an aftermarket exhaust brake.

Has you or the dealer tried doing an "REPLACE ECU" flash (full flash) of the most current calibration? I had two trucks that had a glitch in the calibration that a full flash corrected. Didn't have anything to do the with turbo brake though.

 

[2013 3500 Silver-ado]

Has you or the dealer tried doing an "REPLACE ECU" flash (full flash) of the most current calibration?.

The dealer has seen the truck 3 times for this now problem and tells me that it is throwing no codes, is working correctly and has driven their landscapers identical truck and it drives just like my truck.

My friend has the ability to data log info from the truck to his computer via the OBD and EFI LIVE software.

We have determined that when it is commanding a vane position of 0%, the actual position is down to around 22% for making boost.
And when it is commanded for 100% it is only going to about 84% for exhaust brake.

 

[chevyburnout1]

That's what I'm wondering. The commanded vs actual you would think would be setting a code if they didn't match. The two trucks I had that I did the full reflash on had power issues but no codes stored as well. Just an idea I'm throwing out. I've never seen this exact issue before.

 

[2013 3500 Silver-ado]

Any body ?

 

[testdrive]

I would guess that maybe poor vane performance during this mode might not be coded. However if the vane is commanded to 100% and only able to achive 80% something is wrong with the turbo. Are the vanes being blown open because of excess slop in the carbon build up?

The amount of braking on mine seems to be very much RPM related, the higher the RPM the more brake. And remember the cruise control tries to control speed above and below the set point. Leave the cruise engaged and let the system do the control. The trans will continue to downshift until unable to slow.

I know that my vane position when in the aggressive turbo brake mode is ~99% closed.
Now I know that these two rigs are different, but at 99% it really has a lot of braking power. Granted the RPM needs to be in the 2500 to 3500 range.

sorry if the LML is all together different... Wish I knew more about the factory ones.

 

[2013 3500 Silver-ado]

https://www.facebook.com/photo.php?...1175676715805.27250.1344704716&type=1&theater

 

[DIESELMAFIAPER.LB7]

id tell the dealer to do a full flash and see what that does

 

[chevyburnout1]

Do you have access to another LML to log and compare? If work wasn't such a cluster f*%k right now I'd go grab one off our lot and log it.

 

[jnieberlein]

If it were me I would take the turns back out and the tire pressure back and go ahead an eliminate that as being any possible contributing factor.

Also a little different scenario but my truck will slow better without a load right after I tow then it does when I run around empty all the time. maybe your truck has learned it dosent need to brake as aggressively since you are not heavy, apples to oranges I know, but I like to eliminate little (free) stuff before I get into the expensive complicated stuff. good luck

 

[2013 3500 Silver-ado]

Do you have access to another LML to log and compare? If work wasn't such a cluster f*%k right now I'd go grab one off our lot and log it.

I don't, that is why I was wondering if anyone had any experience, trouble or knowledge that might be of help.

When you get a chance, could you take one for a quick ride and log it for me to compare?

The dealer has been less then helpful and tells me the truck is operating as designed.

 

[2013 3500 Silver-ado]

If it were me I would take the turns back out and the tire pressure back and go ahead an eliminate that as being any possible contributing factor.

Also a little different scenario but my truck will slow better without a load right after I tow then it does when I run around empty all the time. maybe your truck has learned it dosent need to brake as aggressively since you are not heavy, apples to oranges I know, but I like to eliminate little (free) stuff before I get into the expensive complicated stuff. good luck

I aired the tires back up to eliminate that.
If leveling it were the problem, I would think this would be a much more wide spread problem, but I will do that next if I can not figure anything else out.

 

[2013 3500 Silver-ado]

So after the third time the dealer had it, it was fixed.
They told me that they didn't do anything to it. (Interesting)
I would not want to have to admit that it took me 3 times to get it right either.

So for the past 7 months, it has been working great.

Yesterday it started again. Anyone else have any Exhaust Brake problems?

 

[SSchmi5519]

Does it seem to be at all temperature(coolant or ambient) or elevation related?