GQ 'Over Reving'

[GQ1990]

Hi all

I am having a little problem with my GQ Auto transmission (4.2l Petrol) and was wondering if anyone else has had similar?


I have an Overdrive/Power button on the Auto Selector, when this is depressed, the Power light comes on and I get a boost etc etc, the power light also illuminates if I stamp on the accelerator and it automaticaly clicks into overdrive.

The gear change however has started playing up and the Overdrive/Power button is not working and the light will not illuminate when I stamp on the gas..it just seems to over rev..like holding the clutch in.

It appears to over rev working up through the gears, not changing until atleast 2500-3000rpm.

When I used to get to 100kmh it would change into a nice cruiasy gear, 4th I think, but now she just keeps on the revs....

I am wondering if the overdrive is somehow stuck on?

I have read a little about Torque Converters and problems with wiring harnesses and wonder if this is a frequent problem with the GQ's?

Its not a show stopped but don't think it's donig my transmission any good at the moment.

Any help woutl be greatly appreciated!!

[GQ1990]

Hi all

Wonder if anyone can shed any light on this....

My 1990 GQ has started changing gear at higher revs (about 2500-3000rpm).

The Overdrive, activated by the auto selectoris not on but it seems to be stuck in overdrive without the light on?

Unsure if this is a mechanical problem or one for an Auto Electrician.

Any help would be much appreciated!!

Best regards

Matt

[NissanGQ4.2]

Hi mate, have moved your threads into the gearbox section and under one thread rather than 2

Sounds like the Torque converter is not locking

I'm a little confused with power light, do you have a power switch which has a light in it?

[GQ1990]

Hi

many thanks for sorting my posts out, regarding the power light...

I have a thumb switch on the Gear Selector which I assume is the overdrive button, when depressed, I used to get a 'Power' light illuminate on the dash and would start change gear at higher revs.

However, now it changes at higher revs but the Power Light is not illuminated and thumb switch is not depressed.

I'm wondering if the solenoid is stuck somehow, I think i'll open up everything I can and give it all a clean out, maybe some water has got into the electrics?

I'm stumped!

[Ade]

Gday Matt,

This problem is simillar to my tranny when I first bought the Safari about 3 years ago. Mine is TD42 but I believe we got the same model of tranny which only have the power button on the selector stick.

Your tps might be faulty (or need some adjustment) as that is what my problem was. Maybe you can try disconnect the tps, drive it and see what happen. On mine, if I disconnect the tps, it will change gear very fast and need to be driven like manual. I was driving my Safari without the tps for few months until I got a second hand unit from a wrecker and problem was solved.

Cheers,
Ade

[GQ1990]

Many thanks Ade, i'll have a look into it, any pointers on where I can locate the TPS?

[Ade]

I am not so sure on a 4.2 petrol, but it should be close to the carburator as on my TD its on the top of the fuel pump. Tps stand for 'throttle position sensor' and its to send signal to the computer (tcu) of what your throttle is at weither half or full throttle so the tranny will change gear accordingly. My tps is 6 wires and I've seen some only have three wires and it should have a connector close to it and that where you should disconnect it.

I am no expert at these and its all based on my understanding, someone else should shed brighter light.

[Ade]

On the 1st photo is how my tps looks like. I think on the 2nd photo is for carby GQ..

[healy]

On the 1st photo is how my tps looks like. I think on the 2nd photo is for carby GQ..

if you have the carby then its time for a new carby its what im going through rite now on my 3 litre my revs sit s 2g's but once i rev to nearly 3 g's it goes like a turbo is kicking in and its the carby that is a rite off it only works when secondary kicks in

[GQ1990]

Cheers Guys, when I get back home i'll have a look and see what I can find.

Think i'll start by opening everything up and giving everything a good clean out with electrical spray etc.