Rough Idle on Xantia 1.9TD.

Unread post by **KennyW** » 23 Apr 2010, 18:01

Hi all,

I have completed the change over and new timing belt fitted and no change to rough idle.

I am wondering what role the idlling Actuator (1239 in wiring diagram) plays and could this be a possible cause of my problems.

Kenny

P.S. for anybody thats doesn't know it is a bosch pump.

MikeT · Unread post by **MikeT** » 23 Apr 2010, 18:16

I'm unsure what you're referring to as the idling acutator. Does your pump have timing advance solenoid (sits underneath)? If not, your rough idling could be the timing needs adjusting.

If you loosen off the pump and rotate it, the engine note should change. Top toward engine increases the advance, while away from engine retards it.

Unread post by **KennyW** » 23 Apr 2010, 19:13

Hi Mike,

I did that prior to changing the timing belt i made a small difference.

Here is copy of the Bosch wiring diagram, sorry but it is in french.

If you have a book of lies you will be able to identify each part.

Kenny

MikeT · Unread post by **MikeT** » 23 Apr 2010, 20:27

I do have the BOL Kenny, but I'm more interested in the physical location and function of this device. I can only think you mean the fast idle solenoid? If so, then no, it won't cause a rough idle, it just drops the revs to normal idle once the engine warms up.

Can you be more descriptive of what you're calling rough idle and does your pump have any timing control - none, cold start only or full?

Unread post by **Peter.N.** » 23 Apr 2010, 21:24

Listen to the exhaust, it should be even, if its going phut,phut you probably have low power output on one cylinder at tickover, this will also cause the engine to shake. Could be caused by low compression on one cylinder due to wear or insufficient valve clearance or could be a faulty injector.

Peter

Unread post by **KennyW** » 23 Apr 2010, 23:00

Thanks for the replies,

Mike, thats exactly what i want to know the purpose of this and where it is located (idling actuator).

Peter, The car was running fine prior to my problems. the exhaust doesn't go phut phut but there is excessive engine vibration at tick over. once the car is going everything runs smoothly.

A faulty injector can be checked by cracking open each injector in order and when the faulty injector is found there will be no or little change in the running of the car.

Kenny

Unread post by **Peter.N.** » 24 Apr 2010, 08:32

KennyW wrote:Thanks for the replies,

A faulty injector can be checked by cracking open each injector in order and when the faulty injector is found there will be no or little change in the running of the car.

Kenny

I think you will find that if you slacken an injector connection off the engine will try to jump out of the car.

Peter

MikeT · Unread post by **MikeT** » 25 Apr 2010, 17:17

Hi Kenny,

I'm still at a loss to what you're calling rough idle exactly and how timing is controlled on your pump, however...

The idle actuator that I know of sits alongside the EGR solenoid, rivetted to a bracket which is fastened on the two rear nuts of the LHM tank.

There's two soleniods on this bracket (idle and EGR), side by side and both fed by electrical connection and the vacuum pump on the end of the camshaft.

These soleniods tend to fail and the result is continuous fast idle (bosch pump default) and no EGR.

Unread post by **KennyW** » 26 Apr 2010, 10:04

Hi Mike,

I think my description is wrong, I would describe it as excessive engine vibration/shaking at idle speed which disappears as the engine speed is increased.

I hope this is a better description

Kenny

Unread post by **Peter.N.** » 26 Apr 2010, 11:03

Still sounds like uneven power development, could be an out of spec injector, a couple of my XMs do this.

MikeT · Unread post by **MikeT** » 26 Apr 2010, 11:41

What is the idle RPM and is it stable?

Unread post by **KennyW** » 26 Apr 2010, 14:58

Hi Peter and Mike,

The Idle rpm using the REV counter is stable but I don't have access to meter to check properly.

Peter, re the injectors how did you fix your problem

I am tempted to remove this 2nd hand pump put my own pump back on to check and see if it is a problem with the distributor head i.e a small blockage or something similar.

Kenny

Unread post by **Peter.N.** » 26 Apr 2010, 19:26

Sorry I probably haven't read your mail properly or have forgotton - you didn't have the problem with the original pump? Well, unless the pump itself is causing the problem could be some foreign matter got into the injector pipes and thus into an injector, a good thrash on a main road may dislodge it - if that's what's happened.

Unread post by **KennyW** » 27 Apr 2010, 17:03

Hi All,

Sorry about this but I am determined to get to the bottom of this problem.

What is the role of the potentiometer which is on my Bosch pump and could this cause the excessive engine shaking at idle ie the timing of the injection of fuel into the engine

If so how do you change the settings to the correct one.

Kenny

MikeT · Unread post by **MikeT** » 28 Apr 2010, 00:02

Hi Kenny,

It's good to know you won't be letting it get the better of you.

Did your temperature sender(s) test good?

I am unsure how the TPS data is used but the Haynes BOL manual flashes it's get-out-jail-free card by telling us we need specialist equipment to accurately set it, therefore do not touch.

I can't say for certain but expect the TPS is used to calculate timing, along with other inputs. Again, you can easily test it's operating properly using a multimeter set to ohms on the TPS pinouts. Can't see how it would cause the engine to shake and vibrate.

Does your engine have a lift sensor on the third injector?

It could also, as Pete mentions, be the pump or the injectors.

Have you checked the map for a Lexia owner near you?