Intermittent flashes of 3rd gear indicator

[Quik Six]

I'm getting intermittent flashes of the 3rd gear indicator at WOT from the time the car is launched until it makes the 2-3 shift. Not all 3rd gear flashes are followed by KR; however, all KR occurs after the 3rd gear indicator flashes.

I'm not sure what is affected when the ECM receives the signal that the tranny is in 3rd gear so not sure where to look.

Sure would like to get this figured out before I go to the track again.

Thanks.

 

[Ttype6]

I'm getting intermittent flashes of the 3rd gear indicator at WOT from the time the car is launched until it makes the 2-3 shift. Not all 3rd gear flashes are followed by KR; however, all KR occurs after the 3rd gear indicator flashes.

I'm not sure what is affected when the ECM receives the signal that the tranny is in 3rd gear so not sure where to look.

Sure would like to get this figured out before I go to the track again.

Thanks.

When the computer sees that the trans has shifted into third gear,it retards the timing two degrees. If you disconnect the electrical connector at the drivers side of the trans,the computer will think the trans is always in fourth gear and the timing will be low. Disconnect the plug on the trans and see how it reacts.

 

[Quik Six]

Thanks for the reply but my explanation wasn't clear.

What concerns me is the 12-13 flashes that occurred from launch to just before the shift into 3rd gear.

I've enclosed 2 PL files:

5.18 broke 3 teeth off the ring gear. 25#'s of boost. 10.37 @132 MPH.

6.10 run with 24#'s of boost and new set of gears. 10.60@129MPH

Chip is TT SD and WB is PLX. Injectors are 80's with DW pump and BAP. 93 octane fuel and methanol from single 15# line Alky Control system.

 

[RmvBfrFlght]

The pressure switches are normally closed (NC) and provide a ground to the ECM when closed. Then open when the transmission shifts to that gear. Any intermittent connection in the wiring will cause the ECM to think that the transmission is in third gear.

At the ECM it is pin C7, and pin C at the transmission connector. Not sure if there is another connector in between.

Of course the pressure switch could also be bad or the intermittent connection is under the pan.

RemoveBeforeFlight

 

[Ttype6]

Step one. Disconnect the plug at the side of the trans and fire up the Powerlogger.

 

[Quik Six]

T-type 6 I always thought that the change in timing was directly connected to which gear the car was in. Mine was changing to 3rd gear timing at 62MPH but the car stayed in second gear until 86-88 range. Talked to Eric at TT and he said that it was common practice for chip makers to make at the timing change at 62 to let the timing reduction be completed well before the shift to 3rd started.

Received this response from Eric Marshall "Sounds like either a wiring problem to the 3rd gear pressure switch, or a bad pressure switch. That switch does not affect the chip calibration for the SD chip. I don't think the knock is related to that. However, I do see the tranny flaring on the 2-3 shift, which very commonly causes knock (false knock). "

I will be researching tranny flare tonight.

Thanks to all those who offerd their assistance.​

 

[Ttype6]

Talked to Eric at TT and he said that it was common practice for chip makers to make at the timing change at 62 to let the timing reduction be completed well before the shift to 3rd started.​

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I haven't heard of this. I have noticed that my 3rd gear lights up on my Powerlogger before the shift.I thought it was 3rd gear oil acting on the switch but before pressure was high enough to affect a gear change.
If the timing is changed at a certain MPH,the switch shouldn't matter. Maybe it needs the closed switch to activate the high timing before 62 MPH.

 

[Ttype6]

I looked at some of my logs and sure enough,it always lights up 3rd gear at 62MPH.

 

[Quik Six]

I haven't heard of this. I have noticed that my 3rd gear lights up on my Powerlogger before the shift.I thought it was 3rd gear oil acting on the switch but before pressure was high enough to affect a gear change.
If the timing is changed at a certain MPH,the switch shouldn't matter. Maybe it needs the closed switch to activate the high timing before 62 MPH.

I'm beginning to think timing is adjusted based on MPH. Take a look at your spark advance graph on PL.
Timing on mine is 17.6 at launch and stays there until 25MPH then goes to 21.9 until 62MPH and then goes to 19.8 all the way to 132MPH.

What I don't like is the mention of "flare".