Vortec Max Surge

Andrew55 · May 26, 2010

Ok 07 v-max as yall know already. My problem is and has been since new, when Im going up a slight grade or level about 50-55 mph with a slight strain on the engine in 4th gear , I can feel and hear the engine surging, done this since new. At first i thought is was afm related got a tune and turned it off. Didnt help. Try two got retuned and vette servo. Didnt help. It feels like a torque converter related problem of locking and unlocking but not sure. Any opinions/solutions would be greatly appreciated. Also should i give up on my nelson tune and just go Black Bear or Wheatly?

jro909 · May 26, 2010

do the rpms actually fluctuate on the guage or are you going purely by sound?

Andrew55 · May 27, 2010

do the rpms actually fluctuate on the guage or are you going purely by sound?

the rpms do fluctuate a little at arounf 1500-1600 rpms but you can also feel and its more noticeable with the louder exhaust. I can't be the only one that has this problem. I love my truck but it just doesnt feel like something is right.

Andrew55 · May 27, 2010

Guys i know this has probably come up berfore on the forums i just have faith in yall since this is the most helpful gm site on the net. come on you technicians i know your out there....

Stevens03 · May 27, 2010

Any chance you have your Auto climate on

Could it possibly be the air conditioning kicking on and off?

Just a thought.

2005LT · May 27, 2010

Do you not have this issue Steven? Andrew, I notice that all the time on my 09' with the 6 speed transmission too (just showing that it seems to be engine related...unless the torque converters are the same ). I also disabled AFM and it's still there.

I notice it most, like you said, when the engine is lugging at low rpm say to accelerate or climb a hill without forcing a downshift typically with the RPM below 1500. It lunges/surges about the rate of once or twice per second.

Definitely feels like the torque converter not quite holding in a locked state...feels like it 'slips' a little here and there for lack of better description until the RPM picks up and the surges become less noticeable. BB tune may fix this.

Andrew55 · May 27, 2010

Do you not have this issue Steven? Andrew, I notice that all the time on my 09' with the 6 speed transmission too (just showing that it seems to be engine related...unless the torque converters are the same ). I also disabled AFM and it's still there.

I notice it most, like you said, when the engine is lugging at low rpm say to accelerate or climb a hill without forcing a downshift typically with the RPM below 1500. It lunges/surges about the rate of once or twice per second.

Definitely feels like the torque converter not quite holding in a locked state...feels like it 'slips' a little here and there for lack of better description until the RPM picks up and the surges become less noticeable. BB tune may fix this.

Yes mine exactly the same when you dont push the gas enough to make it down shift, rpm around 1500 this is the only time i notice it. If i had the spare money to experiment i would put a higher stall converter but dont know if thats the problem, could also be the variable valve timing in these engines, maybe a BB tune will fix it so I can sleep at night.

Stevens03 · May 27, 2010

No, I don't have the problem... not that I can tell anyways... I do feel the air compressor kicking on and off and why I asked while cruising.

Andrew55 · May 27, 2010

Steven one thing that i see different with your truck is the 4.10 gears most have the 3.73. Maybe with yours turning a little more rpms you dont get this surge...maybe i need 4.10's especially since i have 33x12.50 tires which has made the problem worse.

VT_Z71 · May 27, 2010

When you got your tune & re-tune, did they adjust the shift points for your exact tire size? I had a Blackbear and 285s. When I went up to 295s, I began noticing the exact problem you are talking about. I had Justin reprogram my tune for the new tire dimensions and it is now gone for the most part. If it still does it, its so negligible that it is not noticed.

skp05 · May 27, 2010

I have the same issue with my VMAX. 3:73 2WD Never use auto mode. Really noticeable when pulling a 6,500lb trailer about 1500 rpm. Have never done anything about it.

When you got your tune & re-tune, did they adjust the shift points for your exact tire size? I had a Blackbear and 285s. When I went up to 295s, I began noticing the exact problem you are talking about. I had Justin reprogram my tune for the new tire dimensions and it is now gone for the most part. If it still does it, its so negligible that it is not noticed.

66nova · May 27, 2010

I have 3.73s and the stock 20's and I can't say that I have ever had this problem. At least not on a consistent basis. I do have a Black Bear tune that I got a few months after I bought the truck . So, it's hard for me to say whether or not I had it before the tune.

Smcinc-Ryan · May 27, 2010

Ok 07 v-max as yall know already. My problem is and has been since new, when Im going up a slight grade or level about 50-55 mph with a slight strain on the engine in 4th gear , I can feel and hear the engine surging, done this since new. At first i thought is was afm related got a tune and turned it off. Didnt help. Try two got retuned and vette servo. Didnt help. It feels like a torque converter related problem of locking and unlocking but not sure. Any opinions/solutions would be greatly appreciated. Also should i give up on my nelson tune and just go Black Bear or Wheatly?

I have a 2008 VMax that had the same issue. I brought it back to the dealer several times for this problem, they said they couldnt find it. It was even worse when i towed my boat. I hooked up my trailer and drove it down to the dealership and had the head tech ride with me. They ended up replacing the tourqe converter, and a shift solinod. Got the truck back four days later. Most of it was gone but still has some hitch at the 50-55mph. So I got it tuned and it went away. Justin had to re tune after he adjusted the torque converter pressure. which seemed to fix the issue.

Once in a blue moon if i am on the highway for more then a couple hours at crusing speed the truck will do it. Then it will go away.

Dont know if this is helpful but at least your not the only one that has the issue.

fyi mine has 18k on it now

The first time it was brought to the dealer 1255 miles.

Andrew55 · May 27, 2010

Guys thanks for the replies. I did the exact thing when my was new in 07 took it to the dealer they reflashed/updated the computer , that didnt help so i took it back again and said it was basically a characteristic of these trucks. In my opinion i may be wrong but GM trucks get the best gas mileage of all and to do this they try to keep the rpms down as low as possible, one way to do it is low stall converter. Think about it when you put it in gear it pretty much goes at idle. I have an 84 chevrolet with a 2800 stall converter put it in gear it does move, maybe slightly. I guess what im trying to say is that the trucks that have this surge need a higher stall converter so it doesnt lugg around.??