Fuel Comsumption High On My Xantia 1.9 Td

[Guest pras]

I got 312 miles out of 58 litres of diesel which works out to 24.2 mpg. I am near enough always stuck in traffic in london. I recently had a cambelt and fan belt with full service done on the car. Is this mileage too low?

Is there a way to reset the ecu?

[Johndouglas]

That fuel consumption (if you've measured it correctly) is certainly far too low. If the drop in consumption has suddenly happened since the belt change, I would get the timing checked. It may be one or two teeth out.

[Guest MyBerlingo]

Yes, I agree I had a Peugeot 205GRD when the belt was changed the mpg dropped right down. The timing belt was one tooth out :)

[Guest Colin Hunter]

Yes it certainly sounds as if something is wrong. Shouldn't be an ECU problem unless the car is on of the last of the Mk2 1.9tds.(1997 ot later) Earlier ones didn't have one!

 

If you don't have a manual you will find the relevant info in my Blog at http://my.opera.com/Brecknaheim/blog/ You should be able to figure out if your cam and pump timing is wrong from that. Cheers.

[Guest pras]

Hi sorry forgot to say that the cambelt and full service was carried out on the last quarter of the tank. And thats when I got the 312 miles.

 

What I should have done was to let the new tankful of diesel finish before putting on this new post!!

[Guest Colin Hunter]

Quack Quack OOOPS! :)

[Guest pras]

Am I right in thinking the temp should be around 80 degrees?

 

From cold it takes ages to get to 80 degrees. If I use the heater before this temp it takes even longer. When its at 80 and I have the heater on the temp begins to drop. When I haven't got the heater on and I am driving constantly (not stop start traffic) the temp drops quite low.

 

Can I assume that this is not correct?

Does this waste more diesel?

[Guest Colin Hunter]

Yes. The engine should run at between 80 and 90 Deg C depending on the model.

 

It would appear that your thermostat is faulty. The HDi takes a long time (Comparitively) to reach operating temperature, but the 1.9td should be quite hot within a mile or so. This is due to the indirect combustion chambers having a greater heating surface area to the water jacket than the direct injected HDi. If the engine is running cooler than it should it will indeed consume more fuel as it will be dumping more heat to the surroundings.

 

Changing the thermostat is not particularly difficult. You'll find a pdf of the relevant info here http://my.opera.com/Brecknaheim/blog/ if you don't have a manual.

 

Remember that the cooling system will have to be "Bled" with the use of a "header tank" when re-filling after the thermostat is changed.

 

Cheers.

[Guest pras]

Thanks Colin. How does the engine add more fuel as I thought that the 1995 1.9 TD does not have an engine ecu? And my car idles at 1000 rpm always. Is this correct?

[Guest Colin Hunter]

Doesn't put any more in as such, just doesn't make the most efficient use of what it's getting, so then you press harder on the loud pedal and put it in yourself! Etc, etc! It's a bit like having the central heating on with all the windows open!

 

Does the car feel as lively as it did before the belt change? If it does it's unlikely that the timing is wrong. Cheers. Hope you manage to improve things.

[Guest pras]

The car feels just as lively before and after the belt change. Only after the change the engine was alot quieter. I dont understand your explanation above. What does "press harder on the loud pedal and put it in yourself! Etc, etc" mean?

[Guest Colin Hunter]

It means you depress the accellerator more to make up for the loss of performance. Even though this is not immediately noticeable, you do notice there is something amiss when you fill up the car.

 

The expression "LOUD PEDAL" comes from electric organs and the like where in order to boost the volume of the music you pressed a pedal with the right foot, same as the accellerator in your car. Also the more you rev the engine, the louder it becomes. Hence, LOUD PEDAL! Basically YOU are the ECU. You subconsciously tell the engine to inject more fuel by being a little heavier with your right foot to make up for the fuel being wasted by the broken Thermostat.

 

1000 rpm is a little high. should be around 800/850. Maybe the fast idle/cold start mechanism on your pump is faulty. That could also cause high consumption. If the engine isn't heating up properly then the cold start advance / fast idle may not be coming off. That would definitely cause high consumption. There's a bit in my blog about it. There's a sensor on the engine which links to the fuel pump and controls the cold start. Cheers. Hope this helps.

[Guest pras]

I have now fitted a new thermostat. The only way I will be able to tell if its working properly is when I start the car from cold tomorrow morning. On the old thermostat the spring mechanism is easy to move unlike the new one which wouldn't move!

I let the car reach optimum temp but the car was still idling at 1000 rpm.

 

You say that is no ecu but I have seen a ecu plug-in socket in the fuse compartment under the drivers steering wheel.

 

Which can the cause the worst fuel consumption: the faulty thermostat or idle problem?

[Guest Colin Hunter]

The diagnostic socket isn't just for interogating the ecu for the engine. It will also look at other electronic devices such as ABS (If fitted) and air bags etc.

 

The slightly fast idle speed itself won't use much extra fuel unless you spend the bulk of your time in stop/start traffic. The thermostat will lead to fuel being wasted too if the engine is consitently running colder than normal. It's the cold start advance on the pump which will affect the consumption more if it's not working.

 

There is a sensor on the engine which is connected to the pump for this purpose. I believe it's near the fuel filter. It should cause a higher idle speed and advance the injection slightly when the engine is cold and then return to normal once the engine heats up. If you're not sure about it you could go to a diesel injection specialist to get your pump settings checked out and adjusted as neccessary.

 

It would seem that your thermostat was faulty if you could move it easily. There is a wax filled phial which opens the thermostat when the engine is hot. It would appear that the wax phial had failed. Hope this clarifies thangs a bit. :(

[Guest pras]

Is the technical name for this sensor a fast idle thermostatic sensor? Is it easy to replace? I have been looking at your at fuel system pdf on your blog. Can i assume I have the Lucas fuel injection pump?

Could I adjust the idle by the idling adjustment screw or the fast idling screw?

Thanks again.

[Guest Colin Hunter]

Yes That is it's name I believe. It's some time since I had a 1.9td and I never had any bother with it so I don't know. I can't think it will be any worse than changing the thermostat. There's also a solenoid on the pump which may be faulty.

 

No. If yours is turbo'd it will be a bosch pump. Have a look at the pics and identify it from that. Print out the relevant page and take it to the car to make sure. If you don't fully understand what you're doing then don't mess with any settings as you'll do more harm than good and end up with a bigger bill in the long run. DIY jobs include oil / filter changes and changing easily accessible bolt on bits and changing timing belts if you're confident.

 

I am a fully qualified marine engineer and I think twice before meddling with fuel pump settings. It is so easy to get it wrong. Try the normal idle screw first but don't be too viscious with it. Softly softly is the way with these things. If you do alter any of the pump settings, make sure you count the number of turns (In 1/8ths) on the screw you're adjusting so you can put it back where it was. BE WARNED!!! THIS IS NOT FOR THE FAINT HEARTED!!!!!!!! Just be carefull OK!

[Guest pras]

Damn! I thought you might say that about fiddling with the idle settings. I will get a pro to look at it then.

 

When you say the solenoid maybe faulty, are you talking about the Stop Solenoid?

It was a pain starting the engine this morning. I had to squeeze the prime pump quite a few times to get it to start!

 

As for the new thermostat: It took ten minutes for the temp gauge to get to the half way point between 70 and 80 degrees. And it stayed there all the way to work (no traffic today!) with the heater on. Excellent. And when I finally parked up the temp started to rise. I have also noticed that the fan kicks in alot earlier (when the needle goes just above 80 degrees). Excellent. And the thermostat and seal only cost £10.

 

Here are a few other problems then:

 

I keep hearing a click from the engine bay every 7 seconds and sometimes its a rapid clicking that eventually calms down. I am assuming that this is the accumlator sphere and that it needs changing? Is this sphere the one at the bottom and in front of the engine?

 

 

And lastly the abs is always on. Is there a way to check if the abs sensors are working?

 

Thanks again.

[Guest Colin Hunter]

Yes it may be best to get the pump settings checked professionally. You can ask them to check that the timing is correct from when the cambelt was done at the same time. If it transpires that it's wrong then you have a case with the people who did the job.

 

Regarding the "Solenoid" I may be wrong on this one, but it's a long time since I had a 1.9td (1996 model sold it in '02) and even longer since the 1.9D! Look at section 8 on page 4B.3 of the pdf. It's referred to as an "Electro-mechanical unit" My own (Older) manual calls it a "Coolant fed capsule". Take your pick. It's a bit vague! I think my "Solenoid" is actually on the lucas pump of non turbo models. Again, the pro will know.

 

It's very difficult trying to diagnose a scpecific problem from the opposite end of the country. You can really only make an informed guess at best and a stab in the dark at worst. Reading the relevant passages in a manual and trying to understand the basic operation of individual parts, and how they interact when the engine is running is a good start towards understanding the beast. When you know what it should be doing, you have a chance to figure out when something is not doing "it's" part in the process.

 

Regarding the Clicking noise, that is a symptom of an accumulator fault. If the accumulator has failed there is no "buffer" and the pump cuts in and out instead. I believe BX's would shear the camshaft if this was not sorted as the pump was driven from the free end of the camshaft in these cars!

It is the sphere on the engine front and it is NOT the same as a normal suspension sphere even though it looks like one. In fairness the main part is the same but it has no damper unit built into it. The "throat" of it is open. I wouldn't think it's any more difficult to change than any other.

 

Put the car on the lowest suspension settting and stop the engine. Open the little screw on the accumulator (1/4 to 1/2 turn should do) and you'll hear a hiss as the pressure is released. DO NOT take it all the way out as there is a little ball under it which acts as the "valve" and may be lost. You're Bu****ed then as the system can't be pressurised again til you get a new ball. (Thankfully Citroen have LOADS!)

 

If your abs light is always on you have a fault in the system. The most common are either a sensor or that the "Reluctor" rings on the front driveshafts have failed. See this forum for info http://www.citroen-owners-club.co.uk/citro...?showtopic=4274

 

If you take the car to Citroen they will do a diagnostic on it and tell you what the problem is. That's the only way to tell if the sensors are down. You can disable the ABS by removing the relevant fuse but the car won't pass another MOT until it's properly sorted out.

 

I think we're getting deeper and deeper into a mire of misfortune here! :blink:

[Guest pras]

Hi Colin.

 

I managed to fiddle with the fast idle screw and now I have the car idling at just below 900 rpm. I doubt this is going to better my fuel comsumption but it makes me feel a whole lot better.

 

All cars are bottomless money pits. I bought my M plate with 6 months tax for £500 so I cant complain.

 

I should be able to do most of the work myself.

 

You have been really helpful Colin.

 

Thanks alot!!

[Johndouglas]

I had to squeeze the prime pump quite a few times to get it to start!

 

If you needed to do that, it looks as though you have an airleak going into the fuel lines. Maybe a small split or even a union that isn't air tight.

[Johndouglas]

Just a thought - have you checked all the fuel lines including the return to the tank. I recall many years ago one of our 205's suffered high fuel consumption. Eventually I discovered perforations in the return pipe on the top of the tank. Instead of fuel going into the tank, it was dripping onto the road.

[Guest pras]

I have now finished another tank of diesel. I did 388 miles (of which 110 miles were motorway) and filled up with 54.60 litres of diesel which is 32 mpg. Is this any good? How much mpg should I be doing in a very busy town?

 

How would I check where a air leak in the fuel pipes are?

[Guest Colin Hunter]

32 mpg is at the very bottom end of what I'd expect from a 1.9td (It's not an auto is it? they're not so great on mpg) I know that my type of milage is probably very different from yours but I seem to remember about the high 30's in the winter and low to mid 40's in the warmer weather. On a "run" on the UK mainland it would do about 47/48 with the aircon on so it wasn't bad.

 

The only way to check the fuel lines is to get the car up on ramps and get underneath. trace all the way along the lines to check for fuel weeping out. You should be able to see stains on the underbody if it has been blown along by the slipstream. The same appies for any fuel which may have leaked down over the tank from a return line leak.

 

My Fuel tank leaked from the sender/pump unit under the back seat when the tank was full up. The cause was that the "O" ring on the sender unit had been improperly installed. You can check this by looking under the offside rear seat and removing the rubber "bung" you will find there. The 1.9td will only have a level sender as the lift pump is built into the fuel injection pump. You may find the fuel pipes there but I'm not sure on that one It's a while ago and I can't remember!

 

Cheers. Hope you get to the bottom of it.

[Guest pras]

Thanks again Colin.

 

Its takes me 45mins to an hour to cover 7 miles!!!

[Guest Colin Hunter]

AH! Well, that certainly makes a difference! I'd forgotten about the "RUSH" hour traffic. We're really lucky here in that we don't have much of that. I live about 6 miles from my work and it takes me under 10 minutes to get there!

 

I suppose 32 mpg in that context isn't too bad. Best thing to do would be to fill up the car, zero the trip meter and have a weekend away from stop/start traffic and see how it does then.

 

Cheers