Torque reduction issue

[V8weight]

Some may know that I've been experiencing a strange issue with my car for over two months now. The symptom is that the car seemingly cuts the throttle input for about a half second under moderate acceleration, then cuts right back in and causes a driveline shock. My car has a Eurocharged tune and an MTM tcu chip.
Data logs showed that the tcu was initiating engine intervention (torque reduction), but I couldn't pin it down to a hardware issue with the car (MAF's are good, Lambda numbers are good, timing is good, etc.).
I've now found a new measuring block on the vag that confirmed that the torque reduction is taking place as a result of actual torque exceeding the requested torque specified by the throttle input. At least now I can stop chasing hardware issues, but it doesn't quite narrow it down.
This issue did not exist prior to installing the used ecu with the Eurocharged tune. I ran the MTM tcu chip for about 2 weeks with no issues before installing the chipped ecu. Now, all ideas are welcome here.
My theories are:
A. My car for some reason is making above average power and exceeding the specified torque limits set in the MTM tcu chip.
B. The used ecu I bought is flawed and is sending incorrect torque loads to the tcu via the can.
C. My tcu is junk.

[snoopra]

My guess, C. TCU is toast.

[DHall1]

You already tried the stock TCU prom and the same problem happened. Chance of the TCU being bad? 10%

You can swap in a known good TCU or even swap back your stock ECU and take it to the next step. If it ends up in the ECU (90%) it may prove difficult to determine if its the actual unit or the Eurocharged flash.

[p3u]

Same exact issue here, and same setup, no issue when I had stock, or mtm tcu, but since the flash I have. Anyone having luck contacting eurocharged, I can't get them to return my calls.

[JRS-RS6]

Careful of the smokey monkeys p3u. Pat send me the logs at my Yahoo account and the label file for trans please. We can try my TCU when I get back if I do not have to leave again for work. Since the ECU needs to be coded to the immobilizer that isn't really an option at the moment.

[p3u]

Smoking monkey is welcome on this one. Two cars, same tunes, same tcu, no prior power hiccup. Come 3k at light throttle and slight shudder and lack of torque. Make the car seem stock when it does. When it runs right it is amazing though.

[ben916]

Pat, are you still holding strong with the large aluminum chip taken out of the intake/MAF area? Did the JBWeld hold up?

[4everRS]

I am going with A. That beast makes incredible power. I mean really, it's over 650 ft. lbs at the crank. The TCU is telling the engine to f-off. Not MTM's fault, the stock chip would likely do the same.

[650RS]

Gents,

Sounds like the torque limits in the TCU are being exceeded, having said this when I experienced this nearly every time mine went into LIMP mode.

I would check the TCU for codes if you get a Clutch Circuit Stuck On or Off you more than likely have a bad TQ.

Cheers,
650RS

[snoopra]

My guess, C. TCU is toast.
Sorry, I meant TC was toast (Not enough sleep)

[DHall1]

I can help it if some folks dont understand a turbocharged platform. I suggest reading some basic material on the subject and starting over.

http://www.rs6.com/showthread.php/21076-Dyno-Day

Clearly the crickets in this thread revealed the overall lack of knowledge in the area. But its easier to blame the monkey right? Whatever.

I can only add one more break to the ECU. If PU is having a similar problem then my % of fault goes up. In other words, if the stock ECU fixes the car then the chance the problem is in the Eurocharge flash goes up to 75%. So I think the problem lies in the ECU (90%) and of that 90 (75%) chance its in the flash.

Now, what to do?

Log the car at partial throttle looking at RPM, BOOST and Wastegate duty cycle, then log a stock car under the same conditions. Compare and report.

Now, is that too many if-then's or are we good?


You already tried the stock TCU prom and the same problem happened. Chance of the TCU being bad? 10%

You can swap in a known good TCU or even swap back your stock ECU and take it to the next step. If it ends up in the ECU (90%) it may prove difficult to determine if its the actual unit or the Eurocharged flash.

[V8weight]

Ok, a couple things to add. I soldered in my stock tcu chip during the process of troubleshooting and this seemed to exaggerate the problem, which would lend validity to the tcu not having a high enough specified torque limit, even with the MTM chip.
I've loogged all of those blocks and then some under partial throttle (obviously I'm going to try to log the car and reproduce the glitch) with no usable data. The car boost isn't spiking out of control during this period and the wastegate duty cycle is right in line with what the tune is requesting.
So the conclusion that I'm drawing is that either the specified engine load in the tune is set too optimistically, or the specified load has to be increased in the tcu to match. Of course the problem would go away if I reinstalled the stock ecu, the car would no longer be exceeding the preset torque limits of the ecu itself or the tcu. I'm left with the decision of whether to reduce the specified load in the tune, or raise it in the tcu.

[DHall1]

I dont doubt the EC data points are reached during part throttle. What I'm looking for is how much higher are they from stock levels. I would like to see exactly how much more boost and wastegate duty cycle is applied at part throttle. Then compare to a stock data log.

It would be a simple fix to back off the EC points enough to stop this condition. And IMHO the burden of EC to make it right.

[skribe]

It is a damn sexy tune, and I hate to say it, but it seems like you're beta testing software.

Have you tried adding more ACES IV to the tank? I'm KIDDING, boys, I'm KIDDING!

Best of luck getting it sorted, Pat. Let me know if you want me to roll by EC in person.

[skribe]

Jeebus, just had a thought... I was joking but if a certain additive did everything it said it could... could that not wreak a little havoc on a high-strung 93 octane tune???

[V8weight]

Your thought process is not without validity, but I was having this glitch long before I was running the Aces in my car. I initially thought that the glitch may have been associated with a knock, which is one of the reasons I started using it in the first place. On a side note, I may be in Naperville next week, and thought of driving the beast out and stopping by Eurocharged in person to try to iron this out. Where are you in Illinois?

[terrytcl]

all of these people coming to IL...

:)

i'm near schaumburg (30 minutes straight north).

we should have a meet there

[SAF]

Jerry was supposed to call me when he returned from vacation on Monday but so far nothing. I may try Tony next, but hopefully someone with EC will see this and address it.

I took my first long trip in the car two weekends ago (I'm usually restricted to around town driving) which was 50% open highway and 50% two lane twisties @ 60-80mph. Quite a few times, around 3000rpm I noticed a hiccup when aaplying throttle from a steady cruise. Nothing like Pat has described has happed and I am still TCU stock. I will try to get hold of Jerry, direct him to read this thread and then see about a reassessment of the flash - a face to face back to stock and then reflash test.

Dave, how has your beast been operating?

[V8weight]

Jerry was supposed to call me when he returned from vacation on Monday but so far nothing. I may try Tony next, but hopefully someone with EC will see this and address it.

I took my first long trip in the car two weekends ago (I'm usually restricted to around town driving) which was 50% open highway and 50% two lane twisties @ 60-80mph. Quite a few times, around 3000rpm I noticed a hiccup when aaplying throttle from a steady cruise. Nothing like Pat has described has happed and I am still TCU stock. I will try to get hold of Jerry, direct him to read this thread and then see about a reassessment of the flash - a face to face back to stock and then reflash test.

Dave, how has your beast been operating?
That's exacatly the issue Scott. It's not always sever as I described it, mostly it's just a slight hickup at about half throttle under slight boost. Do you still have my number? Give me a call, I no longer have yours.

[Eurocharged]

Guys - I have talked to Pat and I'm aware of the issue. Scott - I sent you a text message, give me a call when you can.

The Eurocharged shop in Chicago is closed and I'm in the process of moving the shop, dyno, etc down to Houston. I apologize for any communication issues, but the phone system is back up and running 100%.

If you guys have any questions, please PM me or call the shop.

[JSRS6]

Liking the move :-) Will definitely come see y'all next time I'm in Houston.

[p3u]

Any update on the fix?