Help with car surging after cam install

[Whiteoutg8gt]

Hi, I just installed a cam on my 08 G8 and I've been getting some surging deceleration especially when under 10mph. I have idle speed set at 700 and on deceleration when it downshifts into 1st gear it drops to around 600 then will rev back up to around 700 causing the surge(I believe). Just wondering what I need to adjust to solve this problem.

[GHuggins]

You'll want to post the current tune and a log of it happening... Most likely your min air is too low and/or your air adapts and spark corrections are still OE and overly aggressive...

[Whiteoutg8gt]

Ok I have added a scan file along with my latest tune file.

[Joshtuning]

you would have to go to the idle airflow table and bump it up a bit on whatever gear your having trouble and it should fix it

[schpenxel]

I can't get the log to open. Something about invalid file header? Might try uploading it again.

I agree with Josh though.. I'd try increasing min airflow first.

[SultanHassanMasTuning]

you need to tune both MAP and MAF to stabilize the car and get things in line

[Whiteoutg8gt]

I can't get the log to open. Something about invalid file header? Might try uploading it

I agree with Josh though.. I'd try increasing min airflow first.

Yeah,sorry about that. I just tried to open it myself and can't. My computer froze on me shortly after I saved the file and vcm scanner was still open so I think it messed up the file when I shut it down. I'll do another scan this afternoon.

And I have already increased the min airflow by 20% over stock. Would that still not be enough?

[jaydubb71]

Yeah,sorry about that. I just tried to open it myself and can't. My computer froze on me shortly after I saved the file and vcm scanner was still open so I think it messed up the file when I shut it down. I'll do another scan this afternoon.

And I have already increased the min airflow by 20% over stock. Would that still not be enough?

IIRC, I had to go about 30% or more on the minimum idle airflow with my G8. What cam?

[jaydubb71]

Just compared your tune to mine. Add some more minimum airflow...

[Whiteoutg8gt]

Just compared your tune to mine. Add some more minimum airflow...

How much more?

[Whiteoutg8gt]

I have the streetmaster cam from rcr. 219/227 with 612/619 lift, 112 lsa

[schpenxel]

Yeah,sorry about that. I just tried to open it myself and can't. My computer froze on me shortly after I saved the file and vcm scanner was still open so I think it messed up the file when I shut it down. I'll do another scan this afternoon.

And I have already increased the min airflow by 20% over stock. Would that still not be enough?

Log idle adapt advance and try to see what's going on. If it's trying to add a bunch of timing to keep it from stalling then you probably need to increase it more. It won't hurt anything to try some more. With a stock cam on my car I had to bump min air up quite a bit after installing a supercharger (more than 20% for sure)

[jschrock10]

Try this, and see how it reacts:

MinIdle air.PNG

[jaydubb71]

Here is what mine looks like. I have the Livernois Stage 2C... 224/236 620/620 117

minairflow.jpg

[jschrock10]

Pretty similar to mine

[jaydubb71]

Yeah it is pretty close. LOL

[jschrock10]

Also, take away some of the Overspeed/Underspeed spark. You are seeing a 29-30* jump. (idle apadptive spark control) Try to bring it around -8 Over to 9 Under in the gear.

[Whiteoutg8gt]

Here's my latest scan

[Whiteoutg8gt]

I just noticed that when I'm braking when I get to about 7mph the timing drops to -9 or -10 then jumps back up to around 28 or so.

[GHuggins]

Is this thing NA? If so your original min air table was about 1.5 to 2g/s too high. Your min air table in that one was set up more for a cam and blower combo...

I recommend putting the min air table back like it was in your first post, change your percent max and percent max brakes to 2.48, multiply (under you idle tab) airflow proportional by 1.2 and then your idle integral airflow table by .5 and see what this does... There are some other things you can do in the spark tables if this doesn't fix everything...

Then as Sultan pointed out - tune your ve table and MAF both - you'll find this to help A LOT...

Hope this helps.