Thread: Hot & Cold Idle RPM for TDi300

Yep my Tdi300 does the same low idle when cold and a slighty faster idle when warm
Dont wory about its normal for a none computer controled engine the old petrol engines with carby,s did it as well thats why they had a choke

Apparantly the cold idle is a set parameter from the hot idle - get the hot idle right, and the cold should take care of itself. I currently have it at a bit over 750 hot and on cold startup it's about 700. After about 3min idle, it's fine to do a hill start with.

Ok thanks Lads.....so any idea what the factory hot idle is, and how the hell do you read the Disco's Tacho?

I mean, where is about 700-750rpm? I will try and do something that looks like the Disco's Tacho

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I relise that the 1 is 1,000rpm, but is the bould line just above the 0 500 rpm?

So when I set up the hot idle the needle was between the 1 and the small line below it, but still not happy when cold idle as its more like 400-500rpm

Forgot to say its a auto, and I was worried about hi idle rpm for steep decents etc......

Can you use a multi meter or what ever to make sure its running at 750?

It may be that somthing else is causing the low cold revs. I've noticed over the last few years having my disco, that a telltale sign that I need such things as a new air filter or injector cleaner is a lower than normal idle on cold starts ( and not necessarily in winter). I realise each car, due to where it lives can be a little different, but it won't hurt to have a look at other things - how's the fuel filter, sedimenter, air filter etc?

Originally Posted by langy

It may be that somthing else is causing the low cold revs. I've noticed over the last few years having my disco, that a telltale sign that I need such things as a new air filter or injector cleaner is a lower than normal idle on cold starts ( and not necessarily in winter). I realise each car, due to where it lives can be a little different, but it won't hurt to have a look at other things - how's the fuel filter, sedimenter, air filter etc?

Thanks for input. New Fuel & air filters, sedimenter gets drained every 8 weeks for so.

Ive just thought it may be the Diesel being cold and waxing up on cold start up, afterall we are in sth west Vic.......

So can anybody else tell me what the hot idle is ment to be on our 98 TDi300 Disco? Im still not sure what mark on taco is what

Originally Posted by amshaw

So can anybody else tell me what the hot idle is ment to be on our 98 TDi300 Disco? Im still not sure what mark on taco is what

720 RPM plus or minus 20 RPM at normal running temp

Originally Posted by jimbo110

720 RPM plus or minus 20 RPM at normal running temp

Ok thanks bud, so if I set idle at about the red mark below (Disco tacho) it should be close? Do I turn air con on?
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