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-   -   Issues with 7AT after ECU reset (http://www.the370z.com/engine-drivetrain/57255-issues-7at-after-ecu-reset.html)

DarkJak 07-04-2012 12:35 AM

Issues with 7AT after ECU reset
 
I installed CAI's yesterday and after resetting the ECU I've noticed some peculiar behavior with the transmission shifting.

In higher gears, the revs won't be fully locked in. For example, if I'm in 5th, and the revs should be at 2k to match the speed I'm at, the revs would drop down to ~1k when I shift into 5th, vs 2k, as if it didn't grab the gear. Then, when I give it gas, it would rise up to ~3.5k and pull, but eventually drop back down to 2k and lock in. I never had this issue before I reset, and it's bugging me greatly. I'm afraid the gears are slipping or something like that.

Also, the downshift rev matching doesn't always activate when I shift down from higher gears, such as 5-4, 6-5, and sometimes 4-3. It would just get dragged back up instead of popping up. I loved the rev matching feature and I'm very sad that it isn't always working now. A similar thing happens on upshifts. It won't pop into gear, just kind of drag into gear.

Is it possible that I've messed up the transmission somehow? Or have I damaged some wiring when I took the old intakes out?
I'm hoping this is just an issue with the ECU relearning, but I've driven it for over 2 hours so far and every time it seems to lock or shift more aggressively, it'd only go on to limply shift a few seconds later.

Any insight would be nice, whether it's because there is a TSB for it, or I should just keep driving to let the computer readjust more. I'm afraid that it's a mechanical issue, but I'd rather know that instead of driving around with a damaged transmission and damage it further.

Thanks for any input.

Jordo! 07-04-2012 12:37 AM

It's possible that its reading load improperly if the MAF's are either damaged or getting misreads somehow. Check all connections?

DarkJak 07-04-2012 01:28 AM

How fragile are the MAF sensors? I had them in the stock intakes up to the point I put them into the CAI's. It's too late tonight for me to check, but I definitely prefer that happening as opposed to something less replaceable.

IDZRVIT 07-04-2012 02:45 PM

How did you reset the ECU. It's more than just disconnecting the battery for a few minutes. You could revert back to the stock cai and see if the problem remains.

DarkJak 07-05-2012 11:00 AM

I disconnected the battery for the entire install, which lasted over 8 hours because I had to leave for work after I got the intake installed (bumper and brace were still off).

I also pumped the brake after disconnecting to discharge whatever juice was left in the system, a method I read on one of the reset threads. Seemed to work, since all my radio and clock settings were gone and I had to reset the windows.

I might do that as a last resort if it never quite shifts right after a few more days. I don't have any jacks so taking off the bumper was a major PITA, but I think 2nd time through would be much faster since I know where everything is now.

Shifts have been getting better though. The gears seemed to lock in most of the time, 5-7th, and the shift speed has resembled what it used to be a bit more. So I'm hoping that this was just a silly scare, since I'm new to resetting the ECU.

ANMVQ 07-05-2012 12:40 PM

Needs to relearn, I would be to worried about it

Coon-azz 07-05-2012 12:44 PM

Quote:

Originally Posted by ANMVQ (Post 1807156)
Needs to relearn, I would be to worried about it

Does the Z ecu learn down once tuned?
On my pontiac, when we did the ecu reset, we would go out and rail on it so the readings where high just before the 1/4 mile runs, but I know very little about the Z ECU and programing.

Coon-azz 07-05-2012 12:46 PM

Quote:

Originally Posted by Jordo! (Post 1805385)
It's possible that its reading load improperly if the MAF's are either damaged or getting misreads somehow. Check all connections?

consider cleaning the MAF's with MAF cleaner incase something got on them? Are the CAI you installed Dry or Wet filters? I've had issues on other cars where the wet filter style messes up the MAF.

DarkJak 07-05-2012 01:02 PM

They are dry filters, the aFe Takeda CAI's.

I ordered some MAFS cleaner from Amazon a couple days ago. Should get here tomorrow or Monday.

ANMVQ 07-05-2012 01:41 PM

Quote:

Originally Posted by Coon-azz (Post 1807166)
Does the Z ecu learn down once tuned?
On my pontiac, when we did the ecu reset, we would go out and rail on it so the readings where high just before the 1/4 mile runs, but I know very little about the Z ECU and programing.



It can, I know I few guys that have had their cars retuned with UPREV, and drove for a few months car felt different and they had to reflash again. I just redid mine, car was tuned in April, Felt down on accel and power had mine reflashed and feels like a animal again, So now once a day( Or when I drive it) I rip on it at least once.. The Nissan ECU;s do relearn driving habits. :/


And because the tranny ECU is seperate I would guess the same if you cut the power out and reset it. All tho the UPREV will not be erased I just now there has been a few that drove like grandma and the tune relearned a less agressive MAP.

MattP725 07-05-2012 01:54 PM

Quote:

Originally Posted by ANMVQ (Post 1807156)
Needs to relearn, I would be to worried about it

:iagree: shift points, fuel, etc have some variability and are generally learned within the first several hundred miles of resetting an ECU.

DarkJak 07-08-2012 12:17 AM

So it's been over 250 miles now and the shifting is still the same. Torque converter doesn't seem to be locking up.

I did some searching on what might cause it, and a few pages talked about how torque converter lockup is for fuel economy and drivetrain efficiency, and the loss of lock up is usually from the computer having whatever code erased or a chip removed. One page did mention that the MAF sensor sometimes causes it to sense load improperly (MAF cleaner still not arrived yet :/)

Also saw this TSB about ECU damage: http://www.the370z.com/370z-technica...onnection.html
And I'm thinking I may have done something wrong while disconnecting the battery to reset the ecu.

I'm still hoping that it is indeed due to dirty MAF sensors though. It'd be much much easier than taking it to the dealership.


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