Hi all.

 

Collected my 92 uk spec tt auto yesterday after having engine rebuild new turbos etc. Apart from it needing an oil top up and a coil pack tightening all seems to be well.

I was advised to run it in for about 500 miles not exceeding 4k rpm.

 

Here is the problem. In order for me to get the car to change up to third gear I’m having to take her up to 5500 rpm @ 70 mph. In order to stay below the advised 4k rpm mark means going no faster than 45 mph at 4k rpm in second gear. (I hope this is making sense). If I take her up to 5500 rpm to finally get third gear I can reduce speed to 40 mph @ 2000 rpm and it will stay like that until I stop, then the problem starts all over again. This is fine when out in the sticks but not easy to achieve in built up areas.

 

I should say that the car has been in for repair since I bought it so I have no way to tell if this is normal or not, but it does not seem right to me. I have tried building up speed gradually and accelerating hard but the gear change occurs at the same point in both situations. First and second gear changes are very smooth and occur at the right time and I am not aware of any other faults with the box.

 

I am not very technical but have tried to investigate the problem and most suggested things to check (throttle position sensor, kick down cable adjustment etc) would also effect first to second gear changes as well, or would they?

 

So far I have checked the fluid level (ok and clean) and carried out the auto box diagnostic which indicated no faults found.

 

Any suggestions on the possible fault and remedy would be greatly appreciated.

 

Can anybody give me an idea of how a uk spec auto box should perform (speed/rpm/gear change) as I do not want to blow my engine up again or drive around at low speed / high rpm which is uncomfortable and not very economical.

 

Thanks a lot

 

Steve.

 

not really a soloution but may help until u find the prob.. have u tried switching the hold facility on? on mine it makes it change gear alot sooner.

Scoops, it's UK spec - that means I don't think it has hold or power functions.

Scoops.

Being a uk spec the box it does not have a hold facility. Thanks anyway.

Should change up at about 4k, mines does it at about 3.9. Have you tried switching the OD off to see if it makes any difference, you will use engine braking and use more fuel but at least you can get it through the run in period ok.

Hi Steve

the workshop manual has a little diag on page AT-191 which gives all gear change points.In case you do not have access to this here you are:

 

At full throttle D1 To D2 at 42-45 mph

At half throttle D1 To D2 at 29-32 mph

 

At full throttle D2 To D3 at 75-80 mph

At half throttle D3 To D3 at 55-59 mph

 

At full throttle D3 To D4 at 114-120 mph

At half throttle D3 To D4 at 85-89 mph

 

Looking through the diagram on page AT 50 and the read up although fluid probs and filter can cause similar probs it does point to either throttle position sensor fault or incorrectly set, also the inhibitor switch has a seven core cable connector if any probs here it may fool the box in to thinking you have selected D2 and D3,however the kick down switch on the accelerator pedal should be checked if this circuit is shorted or switch stuck down the box will not change up till the higher speed.Try and test again but instead of revs look for speed to see how far out on the table the changes are on both full and half throttle.

 

However it looks like the change pattern is maybe ok

 

Hope this helps a bit. Jeff TT

 

 

 

 

 

 

Take a look at AT-74 in the online manual. There are diagnonses for symtoms that seem to match yours.

Thanks for the replies.

 

I have checked the online manual and it seems to indicate a problem with the throttle position sensor. Just been out with a multi-meter to check the resistances and found that the ohms jump from 1 (no throttle) to 0 (half to full throttle) with no increments in-between. The contacts were bad and I have cleaned them up but this has not affected the readings.

 

Two questions:

1.Could this be causing the gear change-up problem?

2. If the TPS was knackered wouldn’t this also affect the way the engine runs?

 

Thanks.

 

Steve

 

Yes it would affect a number of things. You can run with the TPS disconnected, then the ECU estimates an appropriate value ('makes it up as it goes along' more like!). Try it and see if the gearbox behaves more normally.