Hey all,

You might be able to spot this asap but noone can at the moment. When I drive my TH around a/c on etc on a really hot day and turn it on after its off only momentarily (say 15 min) takes a little longer to start and also the idle drops very low. When I drop it in D, it idles even lower and feels like its gonna conk out on me and the lights even flash on the dash for a second sometimes. I just give it a bit of a rev then she is all good.

What is that mean?

Hey all,

You might be able to spot this asap but noone can at the moment. When I drive my TH around a/c on etc on a really hot day and turn it on after its off only momentarily (say 15 min) takes a little longer to start and also the idle drops very low. When I drop it in D, it idles even lower and feels like its gonna conk out on me and the lights even flash on the dash for a second sometimes. I just give it a bit of a rev then she is all good.

What is that mean?


I'm pritty sure the idle changes on all the cars when A/C is switched on, thats normal.

As for the conk out part, sounds like your idle speed might be too low, theres a idle screw that can be adjusted.

see here:

http://www.aussiemagna.com/forums/showthread.php?t=37699&highlight=idle+adjust

http://www.aussiemagna.com/forums/showthread.php?t=31096&highlight=idle+adjust

otherwise might be the ISC thats faulty.

I've noticed mine does this in the same circumstances you have described (driven to full temp on a warm day, parked for 15-30min, then started again). I'm thinking it has something to do with heat soak into the MAF sensor and / or the engine struggling with the extra hot air at idle.

If your car has an unmodifed intake system, then I would suggest it is more to do with heat soak into maf sensor (particularly the instrument in it which measures air temp) causing issues with the signal it is sending to the ECU (which would effect the ignition timing, and fuel delivery). It shouldn't take more than a few seconds for the cooler air being drawn thru the MAF sensor to cool everything down and therefore the problem goes away.

Thats my theory anyway. Next time you're in a situtation where you think it might happen, open the bonnet for a few minutes before you start the car - that should be enough to let the temps under the bonnet to reduce considerably. I'm not saying this would be a "fix" for it - just saying it will support my theory, and if it turns out to be the case, well I can't really see it doing any damage.

Hmm fair enough. Funny because it all started to happen after I installed a TJ sports exhaust. Ill give it a go. As long as it doesnt mean something really bad shes doin well for 215,000ks :)

I experienced the same thing occassionally last summer under the same conditions too. After getting suckered into the Mitsu reset base idle scam for $40, I gave up and just assumed it was one of the many quirks that magna's seem to have.

Not a big deal me thinks...

You might be able to spot this asap but noone can at the moment. When I drive my TH around a/c on etc on a really hot day and turn it on after its off only momentarily (say 15 min) takes a little longer to start and also the idle drops very low. When I drop it in D, it idles even lower and feels like its gonna conk out on me and the lights even flash on the dash for a second sometimes. I just give it a bit of a rev then she is all good.
How old is your battery?

Heat is very tough on battery; if its anywhere over 2 yrs could be
repeat of our well-known "dodgy battery" idle problem symptoms.


Was driving around stuck in traffic all this afternoon in the heatwave with AC full on.
When finally got back home I popped the bonnet to refill the squirt reservoir... jeez,
everything was stinking hot. Put my hand on steering fluid reservoir = too hot to touch.

And yeah this on a TH with a "real" grille too... hate to think of grille-less KJ.

Last time I changed the battery I didn't bother replacing the TH's battery box cover.
Thought it would be better to let the battery get more air (& donated into the KJ instead)