Engine surge (or miss?)

[CEly]

Driving around the Black Hills this week on vacation, I am noticing what at first seems to be a surge while climbing mild grades (w/o 5er) at a steady speed. Now, after closer observation, the rpm & boost seem to actually be momentarily dropping slightly in 2 or 3 second intervals. I've only noticed this around 50 to 60 MPH range so far. I had turbo replaced recently and a new flash, but not sure which one. Any input would be appreciated as I want to drop truck off at dealer when we return from vacation.

 

[Jim W]

I have notice this on my 08, after I cleaned the MAF sensor. The MAF sensor was plugged with soot and I found a post on how to clean the MAF sensor. I did buy the cleaner for MAF sensor from NAPA to use instead of the home remedies.

I just had the latest AS flash done to my truck (today) that has been posted on this forum, TSB-18-013-08. Driving home from the dealer (5 miles) the surging is not there. I need to drive more miles with and with out the 5er attached to see if this is truly gone. I will post the results in a week or two.

 

[CEly]

So... cleaning the MAF created this for you? Maybe mine was cleaned at the dealer while replacing turbo and updating software. Too bad for all these little issues, this 6. 7 pulls like a freight train when I need it to. Just don't want it to leave me and my family stranded somewhere, especially with a handicapped child on board!!

 

[Jim W]

CEly,

Yes, this was the first time I have notice this issue. I thought that maybe I did not install the MAF sensor correctly or that there was a leak past the o-ring. I have recheck to make sure that the o-ring was not cut and that the MAF sensor was fully seated in the port.

This was not that objectionable to operate but very noticeable to me as I drove the truck. I wanted to get the latest software flashed on the ECM then see if this would go away.

I could not understand how cleaning the MAF sensor could create this issue. But the fully plugged sensor with soot, could have been masking the issue once clean this issue became noticeable to me.

Now with the latest flash (AS) I want to see how the truck is running for a two week period. I will report back to you after the two week period. I will be pulling my 5er to WI, next weekend so I will know for sure if this been fix.

Hope this helps you out.

 

[CEly]

Jim W

Thanks for the input. The problem is tolerable, yet annoying when an owner pays attention to his truck day-to-day.

 

[Lonestar]

I'm interested in the outcome of this thread. I am in the process of driving my new to me 08' w/13k miles home, and am experiencing the same sensation. It's a surge at a constant rpm. I will be taking it truck into the dealer as soon as I return from Lubbock. Please keep us informed as to your findings.



Thanks

Corey

 

[Jim W]

It has been one week since I have had my truck updated to the latest "AS" flash, so far so good no surging notice. I will know more information after I get back from our long weekend trip. I am pulling my 5er to WI on Friday and returning on Monday the 27 July 09. I will post my results after I get back from WI.

As a side note, since I have not filled up yet since the new flash. The OHD has indicated a 1 MPG improvement over what is normally shown. This is mainly stop and go city driving, I will know more when I fill up and calculate the actual mileage.

 

[CEly]

Got appointment for Monday, 27th. We'll see what they say!!

 

[Jim W]

CELy,

Towed today with the 5er in my SIG,traveled 165 miles no issues at all. No surging ran smooth with the new "AS" flash, OHD showed 12 MPG when pulling will not know hand calculated MPG till I get home.

The EGT showed a steady 1000F when under load, this is the first time for this when I pulled before the "AS" flash I would see 800F. When Regen takes place still will see 1250 to 1400F. Regen only once that I could till in the 165 miles, this was a 4 hour drive. The EGT gage showed the 1250 to 1450F for 14 min's.

I will update more on Tuesday after I get home. I hope this helps you and others. Will keep you posted.

 

[CEly]

Just got truck back from dealer. They performed another flash for both engine and transmission. They said there was a stored P1451 code, but I had no CEL on the dash. They performed a regen because the last software update wasn't re-genning properly-hence the P1451 code I guess. They also did an H46 recall-steering related? Time will tell if my problems haved ceased, I'll give an update in a week or so!!

 

[Jim W]

Latest update:

Towed home today with the 5er in my SIG. I filled up on Saturday hand calculated MPG was 11. 9 for both towing and non towing. I then drove to House on the Rock and back to campground then drove home. I have not filled up my fuel tank as of yet, but I did travel over 305 miles with a 1/4 tank left. I have not experience any surging issues like before.

The EGT showed a steady 900 to 1000F when under load, this is the first time for this when I pulled before the "AS" flash I would see 800F. When Regen takes place still will see 1250 to 1400F. Regen took place twice in this mileage once on Sunday and once when towing home. I am happy with the "AS" flash, I hope your truck will run as go this is now running. Keep us posted as to your results.

Jim