Lack of throttle response upon slowing down/re-accelerating (running ECUTEK)

435 Views 13 Replies 5 Participants Last post by 240Z TwinTurbo, 13 d ago

driverx2030

Discussion Starter · 16 d ago

Hey guys,
I'm experiencing some serious throttle response or lack thereof when slowing the car almost to a stop, then re-accelerating again. The acceleration unresponsiveness seems as long as 1-2 seconds sometimes. I mean I will really hit the throttle to the ground and there is no response. I installed a pedal commander today thinking that would alleviate the issue however it didn't

My car has the following specs **(Tuned on Ecutek)
2015 Premium
AAM Competition Stage 3 Tune (COBB)
3 in Boost Logic Intakes
Mid-Pipe
Downpipes (AAM Competition R35 GT-R 3" High Flow Catted Downpipes (GESI HFC))
Tanabe exhaust
1300 IDX injectors
Upgraded fuel pumps (AEM’s 340lph)
Visconti speed density kit

I'm not sure what the issue could be, this wasn't an issue for me really when I was on COBB but started after switching to ECUTEK for some reason.

My tuner ran a log on my throttle vs my pedal depression and it wsa the following (You can see the blue line (throttle) lags the red line (acceleration):

This has been discussed in the following thread: Getting some serious hesitation from engine throttle (Post #36)
The issue was resolved by COBB via some Launch Control map update? However, that does me no good as I'm on ECUTEK.

Any thoughts on what this could be, has anyone seen this before running ECUTEK?

Thanks.

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240Z TwinTurbo

· #6 · 15 d ago

kaane said:
I have seen the same issue a few times. I am pretty sure its transmission related, it feels like the transmission was about to downshift to 1st and then when you engage throttle again it delays. Log transmission and ask your tuner. The throttle won't engage until the shift is finished and at slow speeds it takes extra time.

Agreed and I had a similar issue, but mostly when slowing to a stop on a downward slope. However, I did also see it from time to time when going up the driveway at an angle. I would log all TCM parameters ending in "flag" and also log line pressure.

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240Z TwinTurbo

· #12 · 15 d ago

driverx2030 said:
So I took a TCM data log just now. Apologies, but I included all parameters and highlighted the "flag" and "line pressure" parameters yellow for easier identification. I also got the no response behavior to repeat at the end of the log. I highlighted the area orange where I think it was happening as my Accel Position Sensor 1/2 % shows around 100 at that point. This is where I had the pedal to the floor and no responsce. Not sure if anyone here has any ideas?

I can see it happening in the log, but don't have enough experience to say why. Line Pressure and Line Pressure Target are both OK. As you slow down the trans may or may not have shifted into 1st gear, but you press the accelerator and the car doesn't go. One Gear parameter says it is in 2nd and the other three say it is in 1st. I will assume the ECU cut the throttle because you did not log that parameter. Clearly you have a gap where neither gear is selected as both Clutch A Pressure and Clutch B pressure are at 0psi despite accelerator being 100%. After a second or so Clutch B pressure rises and the car starts to accelerate. I took a screen shot of the graph and added comments, but for some reason I can't find where I saved it. Because you logged 4,000 parameter, I don't feel like going through you log again to recapture the image. Could be tune related and when I had the issue I ended up going back to the stock shift map and have not had an issue since. Must be an issue with the tranny not knowing what gear it is in and the TCM won't allow the throttle to open under the scenario.

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240Z TwinTurbo

· #14 · 13 d ago

In Cobb I can upload a stock shift map so likely you can as well

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