Whilst on a motorway journey - my hot cat light came on for a few minutes. I've read on here that cleaning the contacts PTU might resolve this as it's likely to be unburnt fuel ingiting in the wrong place. I've also read where it is and what it is supposed to look like but I still can't find the damn thing. Has anyone got a photo of what it looks like?

 

Incidentally the posting by Deano suggested that his car hesitated when the light came on - I got something similar. It was slightly lumpy when trying to cruise at a constant speed.

 

Cheers

 

 

 

Rod

Try this...

 

http://300zx-twinturbo.com/cgi-bin/manual.cgi?list=efec&dir=&config=&refresh=&direction=forward&scale=0&cycle=off&slide=4&design=default&total=190

 

The POWER TRANSISTOR UNIT.

I had this problem a year or two back. Apologies if I'm teaching you to suck eggs here, but if it the PTU connection playing up, it'll be causing an intermittent misfire - hence the lumpy running and the unburnt fuel causing your exhaust to overheat.

 

It almost certainly will be dirty contacts; you may as well do all of them while you're in there :)

Hi Rod,

 

Just to let you know that I have cleaned the contacts to the ecu which were quite badly oxidised but the problem still exists. :confused:

 

I have been advised that it could be my O2 sensors, I am going to disconnect them and try it on a long journey one day.

 

Would be interested to hear if how you resolve this. ;)

 

 

Cheers,

 

 

Dean.

Check the coilpack connectors too! You are getting no spark so need to trace the whole ignition system...

 

CheerZ,

 

Andy

Cheers for the help everyone. Just thought of another anomoly that may have contributed. I went to Northampton the other week (about 150miles for me) but didn't see this problem. Now strangely I filled the car with super unleaded fuel and it happened after a 30 mile journey. I'm going to clean the PTU anyway but wondered if there may be a link?

 

Oh thanks for that link Mickey that is a top diagram - shortly after I posted the original message I found the PTU. But the diagram gives much more info!!

 

Cheers

 

 

 

Rod

Oh thanks for that link Mickey that is a top diagram - shortly after I posted the original message I found the PTU. But the diagram gives much more info!!

 

Cheers

 

 

No probs.:)