Autotechnica

Hey guys, I've been experiencing a new problem lately. Basically when I go WOT in 3rd gear, when it's about to shift into 4th I get a really hard jerk forward, almost like the TC has kicked in and cut all my power. I have a NW ASP 178mm pulley with NW PSK. I have considered belt slip, but it doesn't happen in any other gears and I don't "hear" any slip. I've had belt slip before in colder weather, usually 1st to 2nd gear WOT, it's definitely not that. I have tried multiple scan tools and no engine codes are showing up either. The only thing I can think of is some sort of fuel cut. I seriously doubt at speeds in 3rd-4th gear, the TC is kicking in. There's no flashing TC light, so I'm pretty sure it's not that either. I had an issue last summer where my AFR's were leaning out around 5500RPM+, but oddly enough that seems to have gone away. I monitor AFR's closely and I don't see any issues with lean air/fuel mixtures. Any idea what could be going on? I have a eurocharged engine tune which among other things, makes the transmission shift faster. I'm wondering if somehow there is too much load on the transmission and it's kind of a failsafe to protect the tranny? It's also not the S/C shutting off due to high IAT's. I have IAT's monitored and my data logger warns me when temps get high enough for the S/C to shut off. It could also be possible that I'm still having this leaning out problem, but I just can't see it on the wideband when fuel cut occurs. If it is fuel cut, I'm just curious as to why multiple fuel cuts wouldn't throw a code. I literally did this 3 times in a row last night.

Any help would be appreciated. Thanks.

Bry

320 dreamer

do you have the tcu mod? i had the same issues from all 3 gears to 4th it was the tps slamming shut during the shift causing a huge afr spike . tps would go from 90% to 6% during the shift while timing and boost stays the same. after the shift the tps shoots back to 98% causing the hard bang shift . replaced the modded tcu with a oem tcu and it all went away this all happens in approx 400 rpm so its hard to see whiule driving . only while examining the zdl files did i find the issue

Autotechnica

interesting. However, I don't have the TCU mod. Only the Eurocharged ECU

Autotechnica

Hmmm anyone with a 178/185mm pulley have the same problem? Last night I was amongst a crowd of guys with tuned forced induced cars running auto boxes who said that the problem I was describing was common when raising boost on cars with autoboxes. The TCU/ECU does some funny stuff to either protect the tranny or the computer just doesn't know how to shift properly due to the added power. I asked if switching back to the stock ECU tune with the OEM tune's slower shifting would improve this issue. They said no, since delayed shifting will only burn out the clutches in the automatic tranny. Does this sound right? I have 0 experience with automatics as this is my first autobox. One guy with a 600WHP IS300 and automatic told me the only way to get around this is to manually shift 1-2 seconds before the RPM's hit redline and predict when the transmission will actually decide to change up a gear. When I'm at WOT near redline, the TPS will be 100% unless I almost completely let off the throttle, so easing off the throttle before the shift to avoid the hard jerk is out of the question, I have tried this many times and it doesn't work. Another reason I hate drive by wire.

I'm so bothered by this issue, I'm actually considering going back to the stock pulley. To me power is nothing without drivability. Granted, I don't get to do pulls too often that require WOT 3rd to 4th gear shifts, but still. I was going to ask if the TCU tune will fix this issue, but reading the reply above, seems like it makes it worse? Does anyone see any problem with trying out the stock ECU shift pattern? Will that infact burn out my clutches?

thanks.

Lenin

I run a 181mm pulley and I don't have this problem. Had it with the EC TC
U tune but it is gone since I went back to the stock TCU. Post your DashDaq log. Maybe something could be learned from it.

320 dreamer

ok i have been having the same issues and with my buddys research and my new tune i have licked the problem. do a google search for SUPERCHARGER SURGE. its slamming the butterfly closed with the vacuum and then reopening. its a torque management problem. after 3 hrs on the dyno and 3 hrs with the tuner going over all the files in the ecu we have eliminated it and i then went to the track and ran 12.1 , 12.0 , 11.9 , 12.1
im running a stacked setup with a c3 s/c pulley and a pte 178mm fluidamper crank pulley. pulled 22 lbs boost at wot

the issue originally reared its head only with the esp on. with the esp off it would shift fine. during the dyno run it would happen at part throttle with the esp off.

amgen

If you do the "Sneaky ECU Reset", you can experience this behaviour.
It takes a while before it adapts back, and before that you can
feel a jerk between shifts at full power; it cuts and then it comes on.

Gramma_Benz

Call Eurocharged, most likely it's the torque limiter, they can change the tune to fix it.

Autotechnica

I will try it with the ESP off and see if it makes a difference. As far as I know the Eurocharged tune already removes the torque limiters at lower gears. I'm assuming 3-4th gear is when there is the most load. So if I request a custom remap from eurocharged, should I ask for the torque limiters to be put back in place or something else? Thanks.

I've been driving the car for half a year without any ECU reset or battery issues. So the ECU shouldn't have been reset recently.

So the torque limiter should be put back in place or maybe the tune I have doesn't have the torque limiter removed completely and I should have it removed completely?

What kind of info should I log? I seem to be having problems getting a good AFR signal from my wideband, so aside from that, I can log everything else. I haven't logged anything yet, so I assume I just start log with whatever signals are displayed on screen and that's what will be logged?

thanks guys.

320 dreamer

honestly i dont know what the tuner did to fix it other than he worked in the torque limiter files. didnt ask as we were 6 hrs into the dyno day. its something the tuner needs to search for

Lenin

Logging AFRs is very important. I'm sure you know that. I would be looking at AFR, RPM, Speed and TPS%.

Steve, who is the new tuner?

djoa

If you experienced the lean spot on top end, it may be even worse more to lean side, so the SC cuts out and into limp mode.

macbryanie

Did a retune from Eurocharged cure this? I am getting it at WOT from 2nd to 3rd change(limp when it hits the limiter and throws me forward then shifts and kicks me back)
BTW I have added a SL55 intake kit since the EC tune 8months ago if that makes a major difference however am pretty sure it would do it on occasion beforehand.

macbryanie

A reflash did wonders, car has its Mojo back. Sharp shifts. Thank you Eurocharged.