1.9d XUD idle speed ???

fastandfurryous · Post by **fastandfurryous** » 10 Mar 2005, 04:33

... there are in fact 2 systems on XUD injection pumps for cold running. One of them governs the idle RPM, the other operates the Injection timing.
The size-of-a-D-cell-battery-thing-with-a-bowden-cable-coming-out-of-it is there only to raise the idle speed of a cold engine. The only real point for this is so that you don't have to turn up the normal (hot) idle speed to avoid the engine stalling (or idling too slowly) when cold. In reality, for the UK climate this item is almost irrelevant, and for the cost of replacing a dead one, not worth it. I have achieved cold starts in -15 in scotland without this.
The timing advance system is a little more complex. On early pumps, there was no adjustment of the timing, and as far as I'm aware, all Lucas/CAV/Rotodiesel pumps have no mechanism for altering the timing. Early Bosch pumps used a similar d-cell-battery-lump mounted on the front of the pump, and fed by 2 small coolant pipes. This operated a lever on the front of the pump, which you can push by hand and hear the note of the engine change. These equally fail after a while, and leave the pump permanently in it's "hot" running position. Later Bosch pumps (as used on the 1.9TD XUD) have a very tiny bore pipe running from the fuel inlet, down the front of the pump to a bulge on the bottom of the injection pump. This makes use of fuel pressure (or more accuratley, fuel suction) to operate a timing advance when the fuel (and hence the engine) is cold. As this style of engine has the fuel filter on top of the thermostat housing, the incoming fuel to the pump is usually just below coolant temperature.
a 1100rpm idle is indeed rather high. Have you got a Bosch or a Lucas/Cav pump?

roypch · Post by **roypch** » 10 Mar 2005, 11:34

Thanks everyone !
On second look it is not idling at 1100 RPM - it is just above 1000 RPM. Pump is Bosch.
Lever is stuck real hard. I tried pushing it with screw driver, metal rod. Didn't try too much for fear of breaking it.

fastandfurryous · Post by **fastandfurryous** » 10 Mar 2005, 21:32

On the bosch pump there are two locked adjuster screws which relate to the idle speed. access to them isn't great (especially on a turbo model). As you look at the pump, they are on the back of the pump (the side nearest the block) and act on the idle speed lever, which is itself on the back of the pump. The screw nearer the timing belt end is the fast idle max speed screw, and the one towards the flywheel end is the hot idle speed screw. It may be that the two adjusters have been screwed in tight, thus preventing the lever from moving. If you slacken off the fast idle screw a few turns, this may allow the lever to move. If so, slacken the locknut on the Hot idle screw, and then with the engine running, unscrew the adjuster until the idle speed sounds good. Make sure the fast-idle bowden cable is slack during this adjustment.

jakeuk · Post by **jakeuk** » 14 Mar 2005, 00:17

mine idles constantly at 1000 hot or cold, would it improve fuel consumption to turn it down a tad,,,at an amateur guess i'd say it would have to, but you cant beat an experts advice

fastandfurryous · Post by **fastandfurryous** » 14 Mar 2005, 02:54

1000 rpm is a touch fast for an XUD. The change in fuel comsumption for turning down the idle speed will be minimal. As the engine is off load, the only difference will be the pumping losses between 850 rmp and 1000 rpm. I am less experienced with Citroens than with Peugeots, but it may be that the idle speed on yours is that fast to cope with the combination of aircon on, Suspension pumping up, dry steering and heavy electrical load all at the same time. Certainly the recommended idle increase between a non-aircon 405 and an aircon 405 is about 100rpm from 750 to 850, so with all the additional load that a citroen's hydraulic gear places on an idling engine, it may be wise to leave it at 1000rmp, or the engine may stall in heavy load conditions.
It does sound that your fast idle device is working fine though. If the idle speed is no slower when cold than hot it must be doing something.

roypch · Post by **roypch** » 14 Mar 2005, 17:19

Thank you all. I did as suggested - set the idle speed to less than 1000 (a bit above 800) and is steady at that all the time. Had to wait till the weekend to do it.
As you said, the adjusting screws were screwed in tight stopping the lever from moving. May be the previous owner did that to set the idle speed as the cold start device is dead.
thanks again

jeremy · Post by **jeremy** » 14 Mar 2005, 19:16

If you're talking about the thermostatic cold start device being dead - they're not very expensive - seem to remember about £17 from Citroen - admittedly about 4 years ago.
jeremy

Kowalski · Post by **Kowalski** » 14 Mar 2005, 19:28

GSF part number N18862 cost 11.50 + VAT.
The electrovalves are more expensive.

roypch · Post by **roypch** » 14 Mar 2005, 21:48

thanks again friends !
I was under the impression that this(cold start device) is an OEM part and is expensive (?).Is this (GSF part no N18862) the complete assembly - with cable and that cylindrical thing fitted horizontally at the bottom of fuel filter.

jakeuk · Post by **jakeuk** » 15 Mar 2005, 01:45

ive ha enough for 1 day with the piggin fog lights which are now working as they should but my brains now frazzled.but i will look this cold start gizmo not because im tight fisted[:D]i just want the thing to run as it should,i hate it!but i love it too[:D]