Auto transmission 1st - 2nd Shift Problem

[jackchoo]

Hi, been having intermittent issues shifting from 1st to 2nd. The gear seems to get stuck and recovers if I rev >5k sometimes and for those times it doesn't recover, I have stop the car, turn off engine and restart again, then it back to normal. Happens about once every day. Damn annoying and esp dangerous when entering a motorway.

The transmission self diagnosis yields a TPS issue when this happens. Changed TPS, but the problem still persist. Checked continuity from TPS to TCU and ECU everything seems ok! Did a transmission fluid flush (10L) and still the problem exists!

I measured the TPS with a multimeter and jiggled the harness and wires but yielded no problems on the readings.

What else can I do? Could the wires from TPS to ECU and TCU be stuffed intermittently? Appreciate any ideas!!

[jackchoo]

anyone there who can help?? This is a S13 Auto transmission by the way...

update : I notice that it happens quite predictably :-

- from a cold start (after 2-3 minutes warm up)- after 6-7 minutes of driving- at that point I'm normally in heavy traffic so coasting real slow towards the freeway entrance- enter freeway, accelerate- and it cannot get out of first gear!!!- stop the car dangerously by the side- and its all ok for the rest of the journey! till the next cold start go back to the top.

It pulls out a code 43 when this happens (TPS) for the TCM and ECM. But I've already swapped with a good tps and have even checked it on a scope first.

One question though : is the TPS harness 0V reference supposed to be directly grounded to the battery. My multimeter seems to show a direct short to body/battery ground.

[NISTECH]

I thought I already answered you on this but perhaps I didnt. Go to the 240 vert section and find the thread on "94 240 trans" There is some helpful info in there and I suspect your problem is the same one they were having.