i have a light which comes on the left bottom of dashboard, at motorway speeds..its a horizontal hose with heat waves above it..any1 know what this means..ta gary

cats over heating

Gary, your light is the Cat Overheat indication. Sounds like you have a sparking problem. Probably one, or more, of your coil pack connections is braking down............. Or if you have a series one PTU, then it could also be braking down. What is happening, is that some of your fuel is not being ignited, and is travelling down into the cat, and, with the high heat there, is being ignited within the cat. There is a heat (overheat) sensor, which is picking this rise in temperature up, and displaying that you have a fault.

 

 

 

 

Although you now have the answer to your problem, it would have been nice to have introduced yourself first, instead of your first post being a question for help & advice. I'm sure most of the subscribed members would agree with me in saying that we don't mind giving out advice to people who contribute to the site, but for those who just come here for information it would not be a very wellcoming place at all. So I hope you will be the former of that, and welcome to the club ;)

 

Regards,

well i will consider that a proper telling off, im gary, recently brought a 1991 manual non turbo 300zx, in graphite,i was a mitsubishi gto nut, but always had a secret lust for 300zx's, i brought it from a smashing chap in hatfield, with a worn clutch, i just had the clutch replaced, but on the way to the garage i ran out of fuel, the car was running lovely, 2 miles later the car cut out completely, i was towed to the garage to replace clutch & the mechanic said there was a loose connection on the pick up sensor on front cam, but alas its running really poorly since, hence the unburnt fuel/overheating cat problem...sorry about abrupt initial contact, but im a virgin on any forum..gary

welcome to the converted!

well i will consider that a proper telling off......

Please don't take it as a telling off, it did sound rather snotty, and it really wasnt ment to sound like that :slap: . So welcome to the club, and I hope you can sort your problem and rectify it.

I had the same problem as you, I changed the PTU, and all of the coilpack connectors, in the end I just stumbled across the problem while checking somthing else. it turned out to be a damaged coilpack sleave, so a new pack changed my car for the better, so give them a check over as well.

Also have a look through the FAQ section, and at the On-Line Workshop Manual. Always ask though if your not sure on somthing, there are some very knowledgable people on here (a damn sight more than I am) who'll soon point you in the right direction.

Welcome to the club gary...

i have a light which comes on the left bottom of dashboard, at motorway speeds..its a horizontal hose with heat waves above it..any1 know what this means..ta gary

 

Welcome Gary, ditch the cats mate best thing you can do if they start to give trouble :D

thanks for the welcome and advice everyone..gary

blimey...theres some good looking people in this club..just love that shade of purple...

Welcome Gary, ditch the cats mate best thing you can do if they start to give trouble :D

The problem there is, that if you have an ignition problem, this indication is just alerting you to the fact, if you ditch the cats, how would you know of this problem, before it gets worse?

Just a thought.

 

It's like taking a pain killer, instead of sorting out the pain!

 

Or as somone signature on here reads (sorry cant remember who's it is :x: )

"I cant sort your brakes out, so I've made your horn louder!" :rofl:

mine did that the second day i had it, didnt notice the change in engine note because i had the tunes on, the light came on and i was well panicing! pulled over and it was running on 5 cylinders, popped the bonnet and pressed down on the coil pack connectors and it sprung back into life, its cos all the connector clips snap off, and the vibration jiggles it off and makes a bad connection.

youd better have a look at it soon gary cos you'll cook the cats and you'll end up having to remove them anyway

i hope it is just something simple like a bad connection!

OK I've had a new PTU, new coilpack connectors, new plugs, cleaned throttle bodies, no codes on the ECU, fuel consumption is 20.2 mpg av, it's unmodded, running smooth, freshly serviced and I still get cat overheat light from time to time. Beats me!

 

I agree that you would get the light if you are over-fuelling so it's a good tell-tale. But it looks as if this light might also come on "just because".

 

Oddly only JDM cars have these warning lights. No other market thought it worthwhile fitting even though (I guess) all cats would overheat under over-fuelling. Also those lights do not connect to the ECU so overheating cats is not thought important enough to actually do anything.

 

Oh, and according to AndyP / MrF I might be the only Zedder to bother putting them back on! Everyone else just cuts the leads and/or tapes them out of the way.

 

Best guess so far is they mean "warning - please buy new cats" or are just something insisted on by Japan regs.

 

Any other ideas?

there might be a short circuit with the wiring harness (it might have chaffed through the heatshield), or the thermocouple/temp switch (dont know what it'l be) might be faulty. the uk cars dont have them i dont think so they cant be that important.

 

might it have something to do with the type of fuel you're using?

or a lazy/sticky injector?

thanks everyone, it was a bad connection on the coil pack, sorted..