Anything wrong with lower idle speed?

[mrbonk]

Greetings,
The TD42 in my GQ Patrol idles at under 600rpm....lower when the A/C cuts in. I see the recommended idle speed is 700-750, with 800+ when the A/C cuts in. Is there any reason why I shouldn't just leave it where it is? I do notice some funky vibes in various parts of the vehicle at this low idle speed......is that the only reason you wouldn't have it that low? It's been like this since I got it, so presumably the previous owner had it set down there for some reason.

[adam.s]

Just a thought, but maybe its less then adequete speed to keep the oil pressure up ?

It doesnt take much to adjust it back up to where it should be and there are absolutely no benefits to having it 200rpm lower.

[Ingenious-Eng]

Idle speeds on diesels need to be high enough to reduce engine vibrations to a minimum, otherwise other things like A/C compressors, alternators etc. will crack their brackets or mounting bolts very regulary. also it causes extra strain on crankshaft due to the excessivly high harmonics produced.
Cheers.

[Mark2]

I prefer a slightly higher idle so I can idle along in 1st, 2nd or reverse without touching the throttle. Idling in 2nd is a bit of a struggle, my mates 1HZ does it no worries and the gearing doesnt feel much different. Better for shooting, being able to idle comfortably in 2nd.

Mine idles a bit lower when its cold, increases by about 100 rpm when hot. Probably due to thinner oil when hot and tolerances?

[Rainbow Warrior]

I set my idle to 400rpm, but have the hand throttle out normally at around 700rpm, got both worlds when I want it.

[mrbonk]

Ok, so I've reset the idle to 700rpm using the locknut/screw arrangement on the injection pump, but there I encountered my next problem......I don't appear to have an idle-up solenoid/diaphragm for the air con! It's simply not there. I'm looking at the picture in my Gregory's, which clearly shows where it *should* be, but there's nothing on mine. The a/c doesn't stall the engine when it comes on, but it does pull the revs down.

[adam.s]

Aftermarket A/C ?

[adam.s]

I set my idle to 400rpm, but have the hand throttle out normally at around 700rpm, got both worlds when I want it.

When exactly would you want 400rpm idle?

400 - 700rpm, is not a huge difference, I really can't figure out why anyone would want a lower then 700 idle??!?

[mrbonk]

Aftermarket A/C ?

Yeah, it is. I'm assuming the solenoid/diaphragm has *never* been there, because there's no evidence of it having been removed if it was.

I've now discovered that the power relay that appears to control the fan on the front of the A/C condenser is playing up.....buzzing and clicking like crazy and the fan runs all the time, even with the A/C button off. Oh the joys of older vehicles Off to SuperCheap for a new one tomorrow, if I can get one the same.

[adam.s]

Aftermarket A/C ?

Yeah, it is. I'm assuming the solenoid/diaphragm has *never* been there, because there's no evidence of it having been removed if it was.

I've now discovered that the power relay that appears to control the fan on the front of the A/C condenser is playing up.....buzzing and clicking like crazy and the fan runs all the time, even with the A/C button off. Oh the joys of older vehicles Off to SuperCheap for a new one tomorrow, if I can get one the same.

Gives you something to do, car/4by's arn't fun if they never have problems.

Plus would you even blink if yours got scratched? - I'd cry if I spent $80k on a fourbie and it got paint damage in a car park, little alone off road.

[mrbonk]

Gives you something to do, car/4by's arn't fun if they never have problems.

Plus would you even blink if yours got scratched? - I'd cry if I spent $80k on a fourbie and it got paint damage in a car park, little alone off road.

Correct. In fact, I was remarking only the other weekend, as we were making our way through some skinny tracks bordered by trees with low hanging branches etc and copping hits from foliage down both sides, just how unwilling I'd be to be doing that in a brand new $70K vehicle

Mind you, that doesn't mean I'm going to abuse it. It's been well looked after before I had it and the paint is in exceptional condition, so I'm making sure I wash/service it regularly to try and keep it that way. That also means I get to see any damage and rectify it (if necessary) before it gets beyond repair.

I figure the small amount of effort in preventative maintenance will be worth it, rather than having major disasters cropping up with no warning! Plus I'm a born tinkerer, so I'm really in my element now

[Rainbow Warrior]

I set my idle to 400rpm, but have the hand throttle out normally at around 700rpm, got both worlds when I want it.

When exactly would you want 400rpm idle?

400 - 700rpm, is not a huge difference, I really can't figure out why anyone would want a lower then 700 idle??!?

Downhill, small difference really.

[Mintoy]

I set my idle to 400rpm, but have the hand throttle out normally at around 700rpm, got both worlds when I want it.

When exactly would you want 400rpm idle?

400 - 700rpm, is not a huge difference, I really can't figure out why anyone would want a lower then 700 idle??!?

maybe to save on fuel while in traffic.