Very early 1-2 shift

[dewme5]

Have a 1uz and A341E from a 92 SC400. Swapped into a Nissan pickup.

If I get on the throttle hard, the 1-2 shift happens at an "expected" time. But, and part throttle, like taking off in traffic, the 1-2 shift happens at about 5mph. If I step hard on the throttle after the 1-2 shift, it will not kick down. When in OD or 3rd, it will kick down to 2nd. But I have not had it automatically down shift into 1st, yet.

I do not have the SC400 dash (recall reading something about the speedo being in control /back up of shifting). I have not separated the engine and trans, and all stock connectors are hooked up.

Any ideas? I would like to avoid the need for aftermarket trans control just yet, as my budget can certainly go to other aspect for right now.

Thanks.

 

[gloverman]

Have you connected a kick down switch? It needs this to kick down to first. Have you connected the brake light switch? It needs this to drop to first every time you stop. If its not there it will intermitantly drop to first when the vehicle come to a complete stop. Do you have any engine codes or transmission codes? Do you have any live data?

 

[dewme5]

Kickdown switch? If it was on the original engine trans combo, then it is still hooked up.

Brake light switch. I have not wired this into place yet, and will do that today.

Engine codes I have not pulled in a few days. I do not have a w wire on the engine obd I connector. I've tried pulling off of the blue and yellow wire with a light, and it doesn't light up. But, if I measure with my digital multimeter, I can get a 170 Millivolt signal between the blue/y wire and ground. Problem is, the resolution of the multimeter is bad enough that I can't see a good signal. The one time I would love to have an analogue gauge .

 

[dewme5]

Also, to complicate things, I do have the shifter from the donor car, but do not have the wires from it hooked up. Just reading some stuff, that's probably going to cause some issues as well. (I normally run manual trans, and have never messed with an electronic auto).

 

[dewme5]

Was not aware of a kickdown switch, or lack there-of. So I'll try that before I get into much more stuff.

 

[gloverman]

Early engines have a kick down switch on the vehicle body under the accelerator pedal. I would also check the ECU is seeing the correct gears when you move the shifter - these dont come from the shifter unit but from the trans selector switch in the gearbox. From memory they are all in the factory loom. The later engines the signal exits the engine harness into the body harness and then back to the ecu.