Can anyone out there help me? I've got a '91 TT jap import and it would seem that my cats are overheating as the warning light is coming on periodically on the dash. The car, when it's cold, runs fine. But, after about ten minutes of driving she starts to miss, doesn't always accelerate properly untill I floor it completely when she stutters and coughs and finally shoots off as per normal. At this time the warning light goes out too, but as soon as as I try to drive her normally again, within a short while she starts missing etc. again. I'm also getting through twice as much petrol as I used to...any ideas??

Hi,

 

Raz's car did the same thing and it was easily fixed by cleaning all the connectors in the engine bay, especially the PTU contacts. I think I'm right in saying that unburnt petrol is being dumped into the cats and igniting.

 

Go get some contact cleaner from somewhere like Maplins and get cleaning

 

Vijay

or it could be running too weak

Paul C - would running weak cause cat overheating? Originally we thought the cat overheat might be caused by running rich so unburnt fuel gets to the cats, burns and causes overheating cats (and little red light on dashboard).

running weak increases combustion temperatures, and exhaust gas temp

 

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I feel the need, the need for speed!

 

But how would that explain the fact that I'm using twice as much petrol as normal?

when ours was misfiring it was using twice as much petrol as normal too, turned otu to be a bad injector connection, go figure.. oh yeah and ther cat light came on too

 

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[This message has been edited by Clarkey (edited 08-09-2002).]

ok, scrub that - didnt read the bit about using extra fuel !!

 

have you done an ecu diagnostic??

 

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I feel the need, the need for speed!

 

To Paul C. No I haven't. How do I go about that?

http://www.ttzd.com/tech/diagnostic/diagnostic.html

 

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I feel the need, the need for speed!

 

also, mine doesnt seem to have the screw to turn on the ecu, however you can short 2 pins together on the diagnostic socket & get a readout on the engine light. its easier to get to as well, details in the online manual

 

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I feel the need, the need for speed!

 

Just done a post about this on General forum - sorry if there's anything irrelevant but covers the cat overheat light....

 

The lamp is the cat overheat warning. YES the car could well run rough while this is happening. Basically you are getting unburnt fuel into the cats which is then burning inside them and causing them to overheat. This will be caused by an ignition problem. Possibilities are:-

1) Coil Pack connector dirty

2) Coil Pack buggered

3) PTU connectors dirty

4) CAS connector dirty

5) Dodgy spark plug

6) Break in wiring harness

 

What you need to do first (while it is showing the problem) is find which cylinder is down. Do this by removing each connector on the coilpack and listening to the engine revs. If you remove the connector and the revs don't drop, then this is the cylinder you have to concentrate on. Check the coilpack connector and also the connectors on the CAS and PTU. If no joy finding a dodgy (green sh1t inside) connection, try swapping the coilpack from another cylinder then do the test again - has the fault moved? If it has then the coilpack is dodgy...

 

HTH

 

CheerZ,

 

Andy

 

Just a quick note to all you guys who gave me advice, BIG thanks!!!!!!! It turned out to be corrosion on the lower contacts of the PTU just like you said. She's running like a dream now thanks to you lot. Cheers once again. Tim.