Guys, heeeeelp

I’m in possession of Xm 2.5 TD manufactured in ’97.
Car is in good condition, both mechanical and electrical – for now except one thing: on highway I can’t make it more that 150-160 km/h???
In town driving is fine, engine sounds good, no strange sounds, fuel consumption is good – nothing – and still, on the open road – well, that’s my top speed.

Any hints?

Thanks

XM_2.5

It's a difficult thing to diagnose without more detailed info but here's a few basic checks:

1. Throttle cable. Is it just slightly taught with no pressure on the pedal and does the potentiometer travel all the way round when the throttle is pressed to the floor.

2. Fuel filter. Is the fuel filter bowl clean and free from water. Is the filter in good condition. When was the last time it was changed.

3. Is the engine management light on on the dash. If so it may be a duff sensor and the ECU has the engine in 'limp home' mode. Limp home mode gives you just enough power to get home slowly so that you can fix the problem. If this is the problem there are a whole range of further checks required. I'll detail here if this is the problem. Just ask.


Now for the more serious checks:

4. Timing belt timing. Don't trust that the previous owner or his service agent has replaced the belt correctly if it has been changed. I made that mistake to begin with and later discovered the cam 1 tooth retarded and the injection pump 1 tooth advanced. The engine didn't know whether it was coming or going. Haynes covers the setting of the timing belt timing very well.

5. Injectors. Remove all the injectors and take to a local independent diesel specialist and have them tested. It only takes 10 minutes and allows you to eliminate them from the list of possible problems if they are OK. If not, a set of replacement nozzles and springs should only cost about £80.

6. Compression Test. Whilst the injectors are out carry out a compression test. Check for evenness between cylinders and a reasonable pressure. Check haynes for the value.

That's a starter for 10. If you need any more info just ask.

Cheers

noz

Here is what I can tell you:

1.Thgrotile cable – it’s going all the way since I can get the max RPM’s in lower speed or on the idle;
2.I have no warning lights on my dash so …I guess it’s not engine management;
3. Fuel filter was changed, as far as I can see for sticker under the bonnet was changed some 15.000 km’s before and it’s on my top list for changing together with some other things that I intend to do soon as I go back home;

Guess I’m left with the “serious” part but…I’ll be able to check on that in March when I get back.
But just a question. – regarding “serious” part – wouldn’t in that case make some strange noises of show it on fuel consumption or something? Cause, I can tell you that car works so good I wouldn’t even notice anything if I didn’t went on highway !

Anyway, thanks for all your help.

I.

XM_2.5,

If only the injection pump or cam was out by 1 tooth then you wouldn't see so much change in fuel consumption or noises.

I can only tell you about my own experience. My 2.5TD used to be owned by a lady in Invernessshire and had a full service history by the Citroen agent in Inverness. This means that the Citroen agent installed the timing belt incorrectly.

Do not trust anyone unless you check by yourself. The check is very easy. You don't need any special tools and you don't need to take the belt off. Just remove the plastic cover, rotate the engine to the correct position and try to insert the pegs into the correct holes. If they fit, then there's no problem. If you can't get one or more pegs in, then there's a problem.

Let me know if you want to try. I'll tell you exactly how to do it.

cheers

noz

Okay, you got me now
Might be good to check what you saying just to make it sure;
So...please give me some guidelines

Thanks in advance

I.

OK here goes (this is from my memory so please be patient if not exactly right) -

1) Disconnect the Engine ECU, ABS ECU and Suspension ECU. Remove the plastic box which hold the ECU's by removing one bolt at the front. Disconnect the air tubes and remove the box from the car.

2)Jack up the car and remove the front wheel next to the ECU box.

3) Slacken all the 10mm bolts you can see around the outside edge of the plastic timing belt cover. There are about 10 bolts. Don't forget the two bolts in the middle of the plastic. Three of the bolts can be reached from the wheelarch.

4) You should now see the timing belt. Not all of it, only the upper half.

5) Under the car, remove the small metal plate which covers the bottom of the flywheel. (be very careful if you go under the car. make sure you have some kind of support in case the suspension goes down on you)

6) Rotate the engine forwards until the threaded hole in the flywheel lines up with the hole in the engine block. Push an M8 bolt through the engine and screw into the thread on the flywheel. The engine is now at Top Dead Centre.

7) Look at the sprocket on the end of the cam. There is a thick metal fork behind the sprocket. The fork should be pointing at approximately 4 o'clock. If it's pointing at 10 o'clock you need to remove the bolt from the flywheel and rotate the engine by 1 revolution. The fork will now line up with a hole in the cylinder head. Put a 9mm (maybe 8mm)drill through the fork and into the hole in the cylinder head. If it goes in then the sprocket is aligned correctly. If it doesn't, the sprocket is not corrrecly aligned.

8) Look at the sprocket on the injection pump. There are three slots in the wheel. Put a 9mm (maybe 8mm) drill through the slot at 10 o'clock. It should align with a hole in the body of the pump. If it aligns then there is no problem. If it doesn't align then there is a problem.

If either hole does not line up then either the cam sproket or the pump sprocket must be loosened and rotated. If the alignment is really bad and you need to rotate by more than one tooth then the belt must come off and the problem sprocket rotated. If you need to do this, let me know and I'll take you through the process.

When reassembling the engine after your check, don't forget to remove the bolt from the flywheel !!

Best of luck

noz 8)