406 1.9td revving at 1800 - please help

Ross · Unread post by **Ross** » 18 Jul 2011, 12:09

I have a 406 1.9td estate on an "S" plate - 1998 I think - 135k on the clock with no previous problems

I was on the way to work this morning and all was fine - I noticed I was unable to decelerate on the engine and found that when i dipped the clutch the revs initially increased and while I coasted along very gradually dropped to 1800revs

I checked the engine bay and nothing was obvious although I found when I manually pushed what looks like some sort of small "bellows on the pump ? the engine slowed down to normal tickover.

It also seemed that there was no life in the engine and that the accelerator pedal seemed "lifeless" although I think the turbo is still working

Unfortunately I don't have here (at Work) a BofL

I use the car for work everyday so would be grateful of any advice received

Thanks

Unread post by **Peter.N.** » 18 Jul 2011, 12:38

Assuming it has a throttle cable connected to the pump it sounds as though it is sticking, maybe its coming unravelled. Get someone to operate the accelerator pedal while you observe the movement the pump end.

Peter

Unread post by **CitroJim** » 18 Jul 2011, 12:43

Ross, has the pump still got it's damper fitted? This is a thin black tube sitting at a 45 degree angle on the front of the pump. It looks like a baby telescopic shock absorber and sits between the pump frame and the throttle lever.

If it is still there, clip it off and throw it away. They do get sticky and bind. They are there to prevent a sudden snap open of the throttle with attendant smoke. It is, in effect, an emissions device. It fulfills no useful purpose really.

If that;s gone then the return spring just under the throttle lever may have broken but that's unusual. It's a heck of a spring.

Again, if the damper is binding it will make the pedal feel a bit lifeless.

The other damper on the back of the pump is an anti-stall device and normally very reliable. That one is pretty essential as without it the engine may have a tendency to stall on rapid decelleration.

Else, you may have a sticky throttle cable. Some 1.9TD Xantias had a spring damper in the middle of the cable that appears as a thick black tube. I'm not sure if the 406 is so fitted but it will be obvious as a cylindrical 'lump' in the cable. This is known to bind too and many Xantia owners dispense with this too without apparent ill effect.

Hope that helps to resolve the issue.

Ross · Unread post by **Ross** » 18 Jul 2011, 16:14

Absolutely spot on advice - on all fronts - I must have been having a "Blonde moment" at 7am - once I was kicked into gear it was obvious - disconnect the cable clean around the pump and springs and see if it works by hand

All working perfectly and on inspection found the cable inside the sleeve to be twisted up and broken with one strand left

Not one but three good lessons learned

1. Its not always a sensor or computor problem
2. Remember what the old man taught me and look for the simple answer first
3, Remember this forum is still outstanding

On a slightly less positive note I now have a new throttle cable in 13 pieces and Spanish instructions

anyone got a good diagram or instructions in English

Is the pedal the same as the Xantia ?

Thanks again

Ross