Brake band or TCU?

[Kiss Me Deadly]

Hi again)

It occures only while driving on 3. Speeding up to 35-40mph, then deceleration, rpm are dropping down smoothly to 1000 and then start to rise and drop like this: 1000-1300-1000-1300-1000-1300, and finally drop below 1000 only at low speed (5-10mph).
If i select D while rippling it drops below 1000 as usual.

I`ve got QC and power mode mod, no TCU error codes, ATF level and condition is ok, external transmission cooler.

Whats going on?
thanks for advices

[oab_au]

Originally Posted by Kiss Me Deadly

Hi again)

It occures only while driving on 3. Speeding up to 35-40mph, then deceleration, rpm are dropping down smoothly to 1000 and then start to rise and drop like this: 1000-1300-1000-1300-1000-1300, and finally drop below 1000 only at low speed (5-10mph).
If i select D while rippling it drops below 1000 as usual.

I`ve got QC and power mode mod, no TCU error codes, ATF level and condition is ok, external transmission cooler.

Whats going on?
thanks for advices

If you are in selected 3rd gear, and you lift off the throttle, the over run clutch should come on, to give engine braking.
Sounds like yours is not engaging the over run clutch.

If you are in Power Mode, it won't do it, and if the TPS is not adjusted to 0.5 volts it won't engage the clutch.

Harvey.

[Tapani]

I think too high line pressure will do this - like Harvey said first to check is TPS.

This was a feature in the ECUtune chip before Mike fixed it - see the app thread. The solenoid A map was horizontal from a too low TPS value on.

Tapani

[Kiss Me Deadly]

I`ve got ECUtune stage 1 (im not sure of year made, i`ve bought used ECU with it) and i`ve adjusted TPS recently to 0.5 volts, it was 0.43 before adjusting..
Maybe i should set it back to 0.43?

[oab_au]

Originally Posted by Tapani

I think too high line pressure will do this - like Harvey said first to check is TPS.

This was a feature in the ECUtune chip before Mike fixed it - see the app thread. The solenoid A map was horizontal from a too low TPS value on.

Tapani

Yes if the line pressure is too high, it won't engine brake. This is usually the TPS not adjusted to 0.5Volts.
It was his TCU chip that had the engine braking problem, not the ECU chip.

Originally Posted by Kiss Me Deadly

I`ve got ECUtune stage 1 (im not sure of year made, i`ve bought used ECU with it) and i`ve adjusted TPS recently to 0.5 volts, it was 0.43 before adjusting..
Maybe i should set it back to 0.43?

It won't be the ECU.
Make sure that you are checking the voltage between the two TPS wires, not a ground somewhere else, like the battery terminal.

Harvey.

[Tapani]

Right, sorry if I confused you - the ECUTune TCU chip.

I have tried 0.65V - no problems in this regard. With the increased mid range of the turbo engine most of the maps could be scaled a bit..... Too much hassle - modulating with throttle is easy

/T

[Kiss Me Deadly]

Originally Posted by oab_au

Make sure that you are checking the voltage between the two TPS wires, not a ground somewhere else, like the battery terminal.

I`ve checked between white wire and battery negative.. I`ll try today to set it correctly

[Kiss Me Deadly]

The reading was 0.43 VDC. I`ve set it to 0.51 and the problem had gone, but former problem has appeared again - misfiring on 1-3-5 cylinders. Well, now i know its a wrong TPS setting. Today i`ll try to set it to 0.45-0.48, maybe it would be compromise

[Kiss Me Deadly]

Well, i tried 0.43, 0.48, 0.500, 0.511, 0.56, 0.58, 0.60 - the problem still appears on 3.
what to check next?

[Tapani]

With the gear selector in "3" and ignition on, but engine not running - do you hear the QC click at around 2V of TPS signal (depressing the accelerator)?

If the QC is "on" all the time for any reason I believe your line pressure will be too high during engine braking and the over run clutch will not engage.

Harvey can correct .

Get the ECUtuner interface so you can monitor the solenoid duty cycles.

/T

[Kiss Me Deadly]

Originally Posted by Tapani

With the gear selector in "3" and ignition on, but engine not running - do you hear the QC click at around 2V of TPS signal (depressing the accelerator)?

If the QC is "on" all the time for any reason I believe your line pressure will be too high during engine braking and the over run clutch will not engage.

Harvey can correct .

Get the ECUtuner interface so you can monitor the solenoid duty cycles.

/T

Thanks, i`ll try today

Well, it makes constant noise like bzzzzzzzzzzz when the accelerator pedal is on rest, when i depress it, noise dissapear, when i release it, noise come back again. Nothing clicking, only noise

[Tapani]

Yeah, the buzz is the solenoids - but are you sure you do not hear a slight click? I think you should.

If you really do not - check the QC connections and double check them.

Are the shifts more harsh than normal under light throttle?

/T

[Kiss Me Deadly]

Originally Posted by Tapani

Are the shifts more harsh than normal under light throttle?

/T

Yes, they are! Definitely more harsh than they were before

[oab_au]

Originally Posted by Tapani

With the gear selector in "3" and ignition on, but engine not running - do you hear the QC click at around 2V of TPS signal (depressing the accelerator)?

If the QC is "on" all the time for any reason I believe your line pressure will be too high during engine braking and the over run clutch will not engage.

Harvey can correct .

Get the ECUtuner interface so you can monitor the solenoid duty cycles.

/T

The Quick Change can't cause the third gear problem. It only affects the line pressure on the change, not at any other time. It does look at the throttle voltage, but can not increase it, to raise the line pressure.

Originally Posted by Kiss Me Deadly

Thanks, i`ll try today

Well, it makes constant noise like bzzzzzzzzzzz when the accelerator pedal is on rest, when i depress it, noise dissapear, when i release it, noise come back again. Nothing clicking, only noise

As Tapani says; the buzzing is the A solenoid working with the throttle voltage change. At idle, the low throttle voltage is driving the solenoid, to lower the line pressure, to cause the buzzing, with the throttle pressed down, it reduces the voltage to the solenoid to raise the line pressure, so the buzzing stops.

Originally Posted by Tapani

Yeah, the buzz is the solenoids - but are you sure you do not hear a slight click? I think you should.

If you really do not - check the QC connections and double check them.

Are the shifts more harsh than normal under light throttle?

/T

As the A solenoid is responding to the throttle voltage change, as shown by the change in the A solenoid's buzzing sound, It would appear that the throttle voltage is changing as expected.

Originally Posted by Kiss Me Deadly

Yes, they are! Definitely more harsh than they were before

If you start off with very little pressure on the throttle, and it still has a hard 1st to 2nd change, then the line pressure is staying high, regardless of the A solenoids position, and it will need looking at the solenoids voltage signal with a monitor, or the actual oil pressure with a gauge.

Harvey.

[Kiss Me Deadly]

Well, i tried this morning this test again after 40 minutes city driving: i turned ignition on, selector to 3rd and depressed accelerator pedal - QC doesnt make any sound at all, but it still works good.

Is there any way to check solenoids without monitor or oil pressure gauge?

And one more question, when driving in traffic jams, using very little throttle and frequently start-stop, especially when the ambient temperature is hot about 32-35C, the car starts to misfiring very badly - 1-3-5 cylingers doesnt fire (whole passenger side), it helps to restart, but after few minutes the problem appears again - could it be the symptom of the existing problem?