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-   -   Whats correct engine ide speed for 2.5 CRD (https://www.chryslerforum.com/forum/chrysler-voyager-town-country-21/whats-correct-engine-ide-speed-2-5-crd-23763/)

QinteQ 01-13-2015 06:17 PM


Originally Posted by darkcild101 (Post 86586)
9

My car is a manual sir. Number 2 because its an old habit I always drive away in gear 2

- you car is a computer sir, it will forever try to avoid stalling
- best way to do that is start in a high gear .. .. yes that will do it !

QinteQ 01-13-2015 06:41 PM

For those who don't know, but want to get better structured answers to their questions more quickly, putting your country code and SIG line in to your profile helps everyone from any country .. .. to help you. For example GoTo > Quick Links < on the top black banner line, click it, then select > Edit Signature < will allow you to tell others what exact vehicle you have. See below as an example :


2005 Grand Voyager CRD Ltd Edn 2.8L Turbo Diesel Long Wheelbase EURO Wagon (4th Gen [Mk IV] - RG - 53 - H Series) [ US Town & Country Ltd ]
GoTo > Quick Links < on the top white on black banner line, click it, then selecting > Edit Your Details < from the drop down menu, will allow you to tell others which exact country you are in, in my case the UK.


UK

Leedsman 01-14-2015 06:11 AM

In case it helps, most 4-cyl diesels idle at 750RPM or less. My 2.8CRD idles at this speed and it's an automatic; that RPM figure is according to my revcounter. If the engine is governed by an ECM as is mine, the idle speed is set in a program using the crank sensor as an RPM reference and a fixed number put in the program by the programmer (which may well be adjustable from inside the car using a lap-top plugged into the diagnostic socket), so even if you move from neutral to drive, the creep-drag from the torque converter is automatically adjusted for idle RPM by the electronics. The revs will not die due to drag on the engine from the torque converter.
With an engine not governed by an ECM, you have to set the idle a little high in neutral if there is a torque converter drag involved. If the box is manual, there should be no need to set the idle high, as the slight drag from the clutch release bearing is far too small to matter.
So...
If you have a manual 4-cyl diesel idling at 1000RPM, I would say that's far too high and needs to be reduced as it will be inconvenient driving it.

Leedsman.

Vmaxxer 01-14-2015 06:29 AM


Originally Posted by Leedsman (Post 86596)
In case it helps, most 4-cyl diesels idle at 750RPM or less. My 2.8CRD idles at this speed

If you look at the picture I posted and the pic darkcild posted you'll see that the needle is several mm above 3/4 of the 0-1000 mark and closer to 900 than to 750 revs. I checked another 2.5CRD and that one showed the same, so it seems the revs on a 2.5crd are like ~900 revs.
I agree most other diesels I ever had idled much lower.

QinteQ 01-14-2015 07:15 AM


Originally Posted by Vmaxxer (Post 86597)
If you look at the picture I posted and the pic darkcild posted you'll see that the needle is several mm above 3/4 of the 0-1000 mark and closer to 900 than to 750 revs. I checked another 2.5CRD and that one showed the same, so it seems the revs on a 2.5crd are like ~900 revs.
I agree most other diesels I ever had idled much lower.


I agree most other diesels I ever had idled much lower
100% agree with both Vmaxxer & Leedsman even though there is an element of contradiction. If moving a car [Newtons Law] with a mass of say 1,000kg needs a force of say 200n to overcome the resistance and get it going, then it seems logical that moving a car with 50% more weight mass needs 50% more newtons to remove the same resistance. Now the cars software decides the tick-over and darkcild101's thumbnail picture seems ± to be about right to me, particularly as changing the tick-over requires an unnecessary, expensive and risky intervention. The GV with a gross weight of 2775kg is a big lump to move from standstill @ 700RPM. Comparing 'other' cars weighing much less is not a like~with~like comparison at all.

Chrysler GV 2.4 or 2.8, ± 2775kg
Renault Megane 1.9 L diesel Curb weight, ± 960960k
ŠKODA Octavia 2.0-litre TDI CR 150PS Elegance ± 1350kg

Leedsman 01-14-2015 10:05 AM

There is an additional factor in idle speed control if an engine, diesel or petrol, is not ECM controlled: That is, cold-running after startup esp. in cold weather. Due to much increased engine friction, again esp. with a diesel, the idle RPM will be dragged down by this. So it's likely a non-ECM controlled engine will have a higher idle RPM than usual. In the old days (wish I had a quid for every time I've said that) the choke-pull on a carburated petrol engine was arranged to up the idle RPM mechanically for the 1st quarter inch or so to overcome this.
It is possible of course that even with an ECM controlled engine, the ECM designer has forgotten to include remedial action for these kind of problems (and is using old-fashioned techniques. This is likely in the change-over from mech. control to electronic years ago). You also need the "fly-by-wire " system to be able to control idle RPM electronically. I suppose in cold weather with an old mechanical system, a bimetal strip could be used to up the idle RPM automatically in cold running.

Leedsman.

Vmaxxer 01-14-2015 11:28 AM

I wondered about that.
I observe not even 1 rev difference between a complete cold engine and a complete hot engine on my CRD.
My 190E alwasy "ups" the idle RPM a little when the engine is still cold and starts slowing down when the engine reaches a good temperature

Calab 01-15-2015 06:18 AM

Just a quick thought... Could the ECM have some bad "learning" due to pulling away in 2nd gear all the time?

Have you disconnected the battery for a while to clear the learned programming?

Leedsman 01-15-2015 06:40 AM

Briefly -- no. How you drive it is irrelevant for this partic. problem.
Always a good idea to disconnect the battery -ve. for a few minutes to clear glitches, learned prorams etc. Costs nothing, takes no time and might work.
If your engine is ECM controlled and you've tried everything else possible, a reset of the idle speed via a lap-top and the diagnostic socket is indicated if this is an ECM controlled engine. HOWEVER, read all Chrysler's information you can find about your particular vehicle. I find Chrysler's own literature and descriptions pretty good.

Leedsman.


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