Celsior kickdown

[mrshin]

When driving the Celsior, sometimes the auto gets the grumps a bit. If you take off from being stopped with full throttle, it shifts up when it is supposed to. However, if you put the boot down when the car is moving, sometimes it decides it doesn't want to kick down. I was going to substitute the TPS as a first guess, then maybe look at the speed sensor. Anybody got any other suggestions for me to try?

[CrUZida]

There *may* be a switch at the base of the pedal.
As soon as you hit that switch, its supposed to kick down as far as it can.

I haven't bothered hooking one up on my car, as with PWR on, its always kicked down before my foot has reached the floor.

With PWR off, she's a bit sluggish to kick down, and usually only goes one gear.

[mrshin]

I'll take a look, but I don't think it's that because it doesn't want to do the part throttle kickdown either.

[terra]

your car got a second cable coming off the TB to the trans?

that sets shifting 'pressure', how harsh the trans will shift but it may also fix up your problem, which isnt really a problem as the logic is different depending on temperature etc.

adjustment is the same as the throttle, tighten the cable to increase pressure, loosen to make it feel like a slush box.

[mrshin]

Yeah, I'm aware of how the line pressure cable works, but it's the actual gear shifting that's the isssue, not pressure. These boxes are set up FAR too soft at any time, but that's a separate problem!

[SL666]

speed sensor issues are tops.. really..

this doesn't sound like one to me though.. as far as i can tell, no speed signal and it won't want to go out of first, or the alternate is it wants to go straight to top..

[sideshow]

if the speed signal is too fast then i wont kick down

is the car std or modified
has anyhting been done to it recently to cause this

[Matt]

Im not sure if this will help at all, but you could try doing an Auto ECU reset. In the Z30 soarers you just remove the EFI and DOME fuses, let it sit for a few mintues, and then when you turn the car back on, just go through each of the gears P,N,R,D,2,1 and leave it in each mode for a few seconds.

Just go down and up the gears and then give it a couple of quick bursts, 0-70km/h or so and everything should be reset and ready for action.

Either that, or check to see if your floor mats are covering the kickdown switch that may be under the accelerator?

Thats just my guess.

Hope it helps.

Matt

[SL666]

sideshow: i assumed it had been working properly and had stopped, but that is right.. and it wont shift back even if you pull the shifter back until slower than it should..

[mrshin]

It doesn't seem to be a speed sensor issue, but I could be wrong. I'll try resetting as suggested, then I'll try swapping the TPS and speed sensor, check out the switch, and if none of that works I might just consider crying instead!

[CrUZida]

TPS would be my first port of call.
Its the main thing the engine uses for kickdown, and it would have to be WAY out of spec before the ecu would throw a code.

Speed sensor or rpm sensor the ecu would throw a code pretty quickly.

[SL666]

it would be pretty strange for the speed sensor to read too fast.. does some pretty wacky things though if its not right

["Z" UTE]

mrshin, just a couple of things to check:

Does the TRC light in the middle of the speedo light up when ignition is turned on?
If not, replace the bulb.

If TRC light illuminates when experiencing the power shifting probs, then your traction control system is limiting kickdown.

Have you cleaned the throttle body and the butterflies TRC included?

Have you removed and cleaned the ABS sensors at all 4 wheels? (one 10mm bolt for each sensor) The segmented wheel on the driveshafts/stub axles will also require cleaning.

Have you replaced any brake pads?
I have been told that the brake system (ABS) does not like fluid being pushed backward from the caliper. Best to crack the bleed nipple, and bleed some fluid from the caliper, as you push the piston back.

The Tractional control and ABS share the same computer.


Hope this helps, let me know how you go, cheers Chuck.

[mrshin]

This is a poverty-pack car that doesn't have TC. Oh darn.

Out of interest, does anyone know whether the auto trans uses the air flow meter for engine load, or just the TPS?

[CrUZida]

I know of people who have retained the factory ecu purely to control the auto, and then used stand alone for the motor.

In doing that, the AFM would have to have been removed, and reports say that the auto tranny shifts fine.

I'd say it would only use revs, coolant temp, TPS.