Xantia TD stalling after MOT adjustment

roypch · Unread post by **roypch** » 11 Sep 2005, 12:51

My 1994 xantia 1.9 td went for an MOT last week. Previsouly i did tinker with the the idle speed/fast idle and the idle speed was close to 900 rpm (becz of the cold start device is not working). Car failed in the MOT diesel smoke test. It was close to 1.0 last year. this time it is over 5.0 (cut off being 3.5 for turbo i am told). After much discussion our friendly tester/assistant did something to the pump (they turned something 'down' they said) and then the emission is now below 0.4 and I got the MOT.
Although i am very happy with the MOT result

, this car is suddenly acting like a tired cow pulling a cart. At roundabouts i have to floor the accelerator and still it will move like an ant. Two days ago engine suddenly switched off at roundabouts - not always but happens at least once in my trip.
I also noticed that when i pull the accelerator cable with finger at the pump lever end - nothing happens for a while and then only engine revs up.
Since i am scared of the car stalling at roundabouts, i keep an eye on the rpm counter and noticed that sometimes the rpm counter is going well below 400 when i take my feet off the accelerator to change gear - may be this is what resulted in the dangerous stalling at roundabouts ?
Any suggestion/advice on this will be highly appreciated.
(Can this be sorted out by adjusting the clip on accelerator cable - near pump lever so that there is no slack in responding to accelerator pedal ?)
Roy - 1994 Xantia 1.9TD

Unread post by **Peter.N.** » 11 Sep 2005, 13:02

Sound like you have two problems. First they must have adjusted the maximum fuel screw (I assume that its a Bosch pump) tht's the one at the back of the pump where the injector pipes connect, that will cut back the fuel, leading to lower emmisions but also less power. Emmision failure is often due, not to to much fuel, but to an accumulation of soot in the exhaust system, on the way to the test if you thrash it hard in low gear it will blow it out.
The second problem sounds like adjustment of the anti stall setting, this is adjusted by the relative positions of the two levers on top of the pump, the throttle lever and the other one that is connected to the cold running speed thermostat.

citronut · Unread post by **citronut** » 11 Sep 2005, 13:52

usuly to get a disele through the mot they wind back the max throtle stop so it dose not rev as high when they stamp on throtle durin emision test,but it sounds like they have moved the cable adjuster so when the pedle is hard on floor it is not opening throtle fully,this is simple the fix as you just have to pull cable adjuster untill cable is tought but not tight and move the spring clip up to the bracket,also where your revs are to low they must have adjusted the slow running throtle stop which is very strange,besides if the car was running normaly before test what you should have done on route to mot is stick it in 2nd and floor it for a few seconds two or three times also make sure the engine is very hot when you get to test station
regards malcolm

roypch · Unread post by **roypch** » 11 Sep 2005, 16:54

Thanks, citronut and Peter.N.
I have used injector cleaner and the car was given a good thrashing before taking to test station. My suspicion was - whether higher emission is due to the higher idle speed - 900 rpm- which was a result of me tinkering the idle screw.
Car was running ok before the MOT.
MOT fellows adjusted something - with a spanner to hold something and another to adjust - on the transmission side of the pump. They did not do anything on the idle/fast idle screws on the back side of the pump as i would have easily spotted that.
As citronut suggested, I have adjusted the accelerator cable end to be just taut. I shall report back the experience after some more driving. did a quick 20 mile run with a few roundabouts without any stalling yet.
Thanks again.

BonceChops · Unread post by **BonceChops** » 11 Sep 2005, 18:14

If it is a Bosch pump. The max fuel screw has a metal ring crimped around it so it should stand out. This is added after the pump is correctly set up so you cant increase max fuel. If you can spot it, slacken the locknet until it touches the metal crimped ring and then screw the screw in all the way. Finally nip up the locknut. Whenever you are making ajustments to the pump always count the number of turns adjustment you make and write it down. Then if it is worse you can put it back.

citronut · Unread post by **citronut** » 11 Sep 2005, 19:30

adjusting the cable should not alter the min revs unless pump was adjuted wrong in the first place and the cable was holding the revs up which its not ment to do
regards malcolm

roypch · Unread post by **roypch** » 11 Sep 2005, 20:15

I am a bit confused now !. what i am seeing on this car is that the idle speed when it is stationary is fine - between 800 and 1000 rpm - rather close to 800.
Another funny thing is that if it was idling at just above 800 and i stamp on the accelerator pedal to take it to 3000 rpm and release it, idle speed will fall back to something close to 900 rpm. is this normal ?
Accelerator cable was not holding the min rpm in this car i think. If i stretch the accelerator inner cable at the pump lever end, nothing happens for quite a length of cable and then rpm picks up. It was not like this before the MOT adjustment. there was some slack - definitely not this much.
Should i only do the accelerator adjustment ? i.e pull cable adjuster untill cable taut and then put the clip in. won't it hold the engine/pump from occassionally falling back to rpms below 400 as i have experienced ?? (this only happened when i was getting off motorway slip road to roundabouts - gearing down.)
After driving the car for sometime after accelerator cable adjustment, i think it is better than the post-MOT 'on-off stalling' driving last week. but not the same as pre-MOT.
can i do any damage to pump/engine by running it like this ? (I am bit scared of touching the pump )
many thanks again !

Dave Burns · Unread post by **Dave Burns** » 11 Sep 2005, 21:16

The actual adjustment of the delivered quantity of fuel during normal conditions is controlled by a centrifugal govenor and a delicate balancing act by several springs.
What the garage have dons is to upset the ballance by screwing the maximum fuel screw outwards to lessen the amount of fuel being injected and so reduce smoke opacity, however with a reading of below 0.4 they appear to have gone too far with the adjustment.
Now as you have found the throttle lever needs to move further before it places sufficient pressure on the various springs to gain an increase in fueling.
The fact that your car has gone from an opacity reading of 1.0 to 5.0 in the space of twelve months, presumably with no tinkering on your part, suggest that the injectors badly needed servicing rather than anyone making adjustments to the pump.
You can't cause harm by driving it like this but it must feel very sluggish compared to how it used to be.
Dave

citronut · Unread post by **citronut** » 11 Sep 2005, 22:01

mot stations i know and use do no alter the pump setting at all they just alter the throtle stop screws on top of the pump,all this dose is stops the cable pulling the throtle lever to max throtle,so when they stamp on pedle it dose not rev as high as it would normaly
regards malcolm

bxbodger · Unread post by **bxbodger** » 11 Sep 2005, 22:20

The tester has adjusted the fuelling to compensate for worn injectors which are probably now well past their best and leaking from worn tips. The pass standard for a turbo is very low, lower than an N/A engine, so they must be well shot!!!
I think what you really need to do now to get your car to perform properly is get the injectors overhauled. You don't mention the mileage but as your car is 11 years old I'm guessing its going to be well on the road to 150000 at least.
I did mine at about 210000 as I got a warning at the last MOT- it sailed through this year on fast-pass with a compliment from the tester and I now don't see any smoke at all-even under load.
Consider the injectors as consumables- and at the £100.00 or so it will cost to have them overhauled its a bargain over the eleven years of service they have given-cheaper than spark-plugs!!!!![:)]

roypch · Unread post by **roypch** » 11 Sep 2005, 23:45

thank you all again !.
Mileage of this car is 130,000. I did tinker with the idle setting in the last 12 months as idle speed (when hot) was between 900-1000 rpm. I brought it down a bit but honestly it was not done properly - hot idle at the time of MOT was close to 900.
I found the car generally ok and returning good MPG - close to some of the figures reported in this forum. my driving is generally around 60 miles per hour on motorways. It was brought with 120 ,000 miles second hand and full citroen dealer service history - hoping that it will run at least 2 years

Dave Burns said "presumably with no tinkering on your part, .." - as i said i did tinker with the idle and fast idle screws to bring down the hot idle speed a bit. when doing that i made a mess of that job - as there is no change in 'hot idle speed' when i unscrew that screw (hot idle screw - one on transmission end of pump) alone. I need to unscrew the 'fast idle screw' as well. is it how it works ? I am also assuming that hot idle means 'idle speed' in Haynes book terminology - idle speed under normal engine temp.
thanks again

Dave Burns · Unread post by **Dave Burns** » 12 Sep 2005, 01:27

Aha the murky waters becoming a bit clearer, <font color="blue">"(hot idle screw - one on transmission end of pump)</font id="blue">" looks like you have had hold of the max fuel screw which would explain the huge jump in emissions.
This screw is at the end of the pump, above the stop solenoid, is this the one you've been twiddleing.
Dave

roypch · Unread post by **roypch** » 12 Sep 2005, 01:56

Thanks for that Dave !
The screw i adjusted (hot idle screw) is the item 4 in the Haynes manual (for xantias 1993-98)Fig 13.14 (Page 1B.12). I could not lower the idle speed to 800 with this alone. so i had to tinker with Item 1 in the same diagram as well (fast idle stop screw).