Darin Schnoor

After installing a VRP 76mm clutched pulley, I've been experiencing a very odd issue. On every upshift, the SC disengages for ~0.5sec before re-engaging (the car has a RaceIQ ECU tune for this specific pulley. And I've confirmed it's not the tune by going back to the stock pulley and having the issue go away, only to reappear once the VRP pulley is re-installed. It also has the RaceIQ TCU tune). It's extremely jerky to drive because the SC is engaged, there's an upshift (and it disengages), followed by a slight pause before it re-engages. It's like power -> no power -> power, all in about a second. Extremely jerky, almost like a student driver learning how to drive a 5-speed. I thought it might be belt slip, so I installed a BWK, but it made zero difference.

I've had zero luck contacting VRP via phone, but I'd like to try exchanging this pulley for another one. Before I bark up that tree, anyone have any ideas? It's annoying af, and literally difficult to drive on rainy roads, which in the PNW are going to last for another 6mos....

GinDistiller

Have you measured the pulley gap? Aftermarket pulleys tend to sit further out so if you reinstalled the same shims it may be too large of a gap and make engagement harsh. You should be able find gap specs in a quick search, I don't remember them off the top of my head.

Also, the smaller pulley makes a lot more boost, which will affect the torque management in the TCU (most noticeable after shifts) so I'd highly recommend the zerocat (a member on here) TCU tune as it basically gets rid of that, something that RaceIQ can't tackle with ECU tunes alone.

oneslow55

99% of the time it's not tune related but more so a error on install or car your car had a small existing problem and the smaller pulley aggravated the situation. Check the gaps and intake leaks.

cnterline

Are you data logging ? Need to see what the TB is doing on shifts , the added power could be messing with tq management, need to see your boost psi and where it is , hitting the rev limiter could do this also , no data logging your flying blind

PieRat

he says every upshift but maybe he meant every WOT upshift. if its shifting fine medium throttle or when commanded to earlier in the rev range via Manual mode paddles (During WOT) then torque management and you need a zerocat tcu tune (do not get another vendors tcu tune they don't remove torque management like zerocats). If its having problems with EVERY shift could be a fault with pulley.. I do recall someone having a lemon pulley from VRP once. if I recall the new one fixed there issue whatever it was..

checking gap is good but I'm sure VRP instructed that in their install instructions so you've already got that on point..

Darin Schnoor

Yep I checked the gap with a feeler gauge before taking off the stock pulley, and it was at 0.016" which is dead in the middle of factory specs. I needed to remove 3 shims when installing the VRP pulley, but it's at 0.016" now too.

I also have the RaceIQ TCU tune, which I imagine should have addressed any potential trans issues, but I'm still new to the M113k platform so maybe not?

See above, gap is a 0.016". I have no signs of intake leaks but I'll break out the smoke machine and check. Thanks for the tip!

Agreed, data logging would be super helpful. What hardware/software is out there for this? Again, I'm new to MB and the M113k platform so trying to learn as much as I can.

It's actually every shift, not just WOT shifts. If I'm in enough throttle to get the SC engaged (more than 10% or whatever it is) the problem happens. If I stay at very low throttle and keep the SC disengaged, the problem does not happen. I've noticed it both in Comfort and Sport, and in manual mode as well.

RaceIQ has a really good reputation AFAIK, and I purchased the ECU and TCU tunes at the same time after sending them the pulley specs, so I would be surprised if they flashed a TCU tune that was incompatible with the pulley. I also tried resetting the trans adaptations but that made no difference. The zerocat TCU tune sounds awesome, but I'd hate to essentially throw away the $300 RaceIQ tune after just a couple of months.

machild

If you go with zerocat he provides a replacement TCU (with more to it than just having a tune) so your current TCU could be resold to offset the cost. Hope that helps.

oneslow55

i fixed my lag actually in the tune...Your spec is to close that will cause issues too..aim for .028 to .032

Timing corrects lots of things

PieRat

hey man try running the 76mm pulley with the stock tune see ifit works. Probably safest to only do minimal wot runs like this but car should still be pretty safe as it can read the boost off the map and fuel somewhat accordingly.

Some cars don't seem to like raceiq tune i could never get them to work in my car fuel trims off by 15%+ and the car would drop out of gear at WOT shifts seemed to over rev and hit a failsafe i had to restart the car to get back into gear due to limp mode I guess...maybe similar issue for you? Tony tried a few things to fix then gave up no refund so raceiq suck in my book but many happy customers so jury is out on that one.

I'd try resell the TCU as suggested and get a zerocat tune.

Eurocharged tunes always been bang on for me and worked flawlessly for the past 6 years or so and I bash my car poor girl..

oneslow55

fyi that advice you gave make no sense i would not load a stock file and do wot on 3 to 4 psi extra boost..That's the first i heard that about race iq as i ran it before.

PieRat

Only way to ensure its not the tune is to remove it. sounds like he'll be able to tell without WOT.

Ls1toAMG

Does it do the exact thing at wot? Is it possible it's belt slip when you upshift?

99lightning

raceiq sells the ndash just get the whole set up from him and log it Tony uses that as well makes life easier on both ends get the bung welded in for the wide band too.

Darin Schnoor

Interesting, that might work then.

Timing is important, of course. But timing isn't measured in thousandths.... Are you referring to the pulley gap?

Right now I don't have the ability to switch between the stock and RaceIQ tunes. I'll have to figure that one out. But if I switch back to the stock pulley with the RaceIQ tune, the problem goes away. That would likely rule out the tune, though it's not a total guarantee.

Honestly I don't recall if it does it at WOT< I'll need to try that. I doubt it's belt slip as I just installed a brand new belt and BWK. Especially considering it happens at even ~30% throttle, let alone WOT.

I'll look in to that, thanks!

Slider

I've been driving with a 76mm pulley from VRP with the stock tune for a few days. I'm not sure we're experiencing the same issue, but I'm still getting the same SC delay that I was before the smaller pulley; but at least the belt slippage/chirp is gone.

I'm taking my car in tomorrow to install the tune and will have them look at everything to see if there's a way to fix the annoying lapse in power when the SC engages.

Fortunately for me, it only occurs one time if the car has come to a stop. After that, it's fine.

Darin Schnoor

Solved!

I spoke with Anthony at RaceIQ, and he informed me of the ECU adaptations the M113k uses. Frankly I had never heard of ECU adaptations. Transmission? Sure. ECU? Not so much. He figured that would be a good first place to start. I borrowed a Foxwell tool from a friend and sure enough, under the ECU section of the MB Tools, there were the 3 adaptations and a reset function. Reset all 3 (timing, a/f, and one other that I don't remember) and the car drives perfectly now. No jerkiness, no weird SC engagement, just freight trains of power! So for anyone experiencing something similar, try this first.

GinDistiller

Great! Also look up load learning as those were all reset w/ the adaptations. Some are a pain/impossible but there is one that you rev the engine at 2500rpm in park for 30 seconds, it has to be after you've driven for a few miles after the reset, but it may get stuck in re-learning before you do that. Otherwise it should populate all the tables over time. These cars are so high maintenance haha.

Mr Bike

Which Foxwell scanner (model number) was able to do the reset?

Schfifty_5

Would unplugging the battery for a few minutes reset the adaptations as well?

PieRat

yep 10-15mins definitely resets the fuel trims so I assume the others as well.