Diablosport Forums

U7135
Latest Rev.
2006 Charger R/T

So Im running 91 CAI Perf tune, but am running 92 Oct. ( highest I can get here) Lately I have been getting some surging at various speeds, usually around 1500 - 2000 rpm. It is very subtle, while in cruise it is the most noticeable. Trying to describe it is hard but it is a very short burst, 1- 2 seconds tops. really makes no speed change, but you can feel it in the seat.

I did some data logging, not really knowing what Im looking for...I logged most of the Knock sensors I think. My numbers were changing depending on throttle etc.

This is what I copied from the Pred.

KNK_MAX_TOT - 10-50
KNK_SNS_V1 0.63
KNK_SNS_V2 0.48
KNK_TOT_RET - 125.50
PDL_POS % - 1.00

Any suggestions.?

Thanks !

Have you tried turning off MDS which may be what you are feeling for that short burst. I recommend getting a CMRTune. LT and ST Knock are what you are wanting to datalog.

You may want to check this out also, it is by XE Ryder:

http://www.chargerforums.com/forums/for ... y.php?f=31

Right, you don't need to log all that stuff. I generally log LT KR, ST KR, Throttle %, engine rpm and speed.

BlueSunshine wrote:Have you tried turning off MDS which may be what you are feeling for that short burst. I recommend getting a CMRTune. LT and ST Knock are what you are wanting to datalog.

You may want to check this out also, it is by XE Ryder:

http://www.chargerforums.com/forums/for ... y.php?f=31

Thanks,
I have tried turning off MDS, does not seem to be the prob. Besides< i am taking a road trip next week and want MDS to kick in to save some $$. Any how, IM ure it is not MDS..thanks for the info, I will log the kr you referred to.

Mike_Levy wrote:Right, you don't need to log all that stuff. I generally log LT KR, ST KR, Throttle %, engine rpm and speed.

Thanks Mike, I ll try that tomorrow.

I logged the above suggested, I saw no knock at all, but this surge is happening more now I was running at 52MPH , rpm was bouncing around 1600, it would surge forward to almost 1700. I went back to stock tune and the problem disappeared..

SO I guess the title of my thread is wrong, should be ;
"91 CAI tune- getting surge"

residentalien wrote:I logged the above suggested, I saw no knock at all, but this surge is happening more now I was running at 52MPH , rpm was bouncing around 1600, it would surge forward to almost 1700. I went back to stock tune and the problem disappeared..

SO I guess the title of my thread is wrong, should be ;
"91 CAI tune- getting surge"

I know you have already tried to disable the MDS but you know have to disable the egr with it. IF you are running 9r04 crom. Anyway the first time I installed a tune my car reacted the sane as your so I un installed the tune and no more surge or MDS Pulse as it has come to be known as. So I just turned it off and the EGR too. I have tried to re-enable the egr but it enables the MDS w/ surge.

I am having the same problems but the lights all flicker at the same time as well. You guys ever get that?

CaptainJ wrote:I am having the same problems but the lights all flicker at the same time as well. You guys ever get that?

That's an electrical issue for sure you may want to take your vehicle to the dealer and describe the problem.

No, because I loaded the stock tune back in and the problem went away. Put another caned tune in and the problem came back.

And you're saying your light flash when this happens? What speed and throttle position?

Could it have anything to do with :
Blinker mod, Brake Pulser and Rear Turn Signal Sequential Flasher.
??

That is what I was thinking because it is electrical. I checked the connections and sent a email to the guy. I was thinking more along the lines of the car is stalling for .5sec (lights go dim and car loses power) car restarts (power surges back and lights return to normal). This all happens very fast but can be felt and seen.
It is easy to remove those mods. They take 10min to install. Plug and play. I am going to remove them just to be on the safe side but remember the car returns to normal when the stock tune is put in.
Another thing I was thinking after reading some threads here and other places, was that the MDS, EGR, and Cruz Control may be the issue.

Your thoughts?

Update.
Running the 91OCT CAI tune.
Firmer Shifts
Lower Fan Settings (Do the fans draw enough power to temporarily cause the lights to dim)
Idle up 50 in D with AC ON
Idle up 100 in P with AC ON.
MDS OFF
EGR OFF
Fuel 2% Rich in all 3 RPM bans
No speed limiter

Now the power surge is gone!!!!
Must have been the MDS and EGR getting turned off.

However, the lights still dim a little periodically but not as bad as before. What could be causing this?

Also, I have a flat tire now

CaptainJ wrote: Also, I have a flat tire now

I read where Diablo is really hard on air pressure. Try adjusting the flux capacitor setting to 1500 jiggawatts.