engine mounts or injectors ????

Mosser · Post by **Mosser** » 22 Jul 2004, 03:56

I have now driven 1500 miles since i rebuilt the head on my 406 1.9td and when i first start it up in the morning it is find and idles nicely and quietly, But once i have driven about 10 miles the engine starts to shake so bad at idle that it feels like i have got massage chairs fitted in my car, and there is a metallic tapping noise that is there as well ance the engine starts shaking, its quite quiet and rises in time with the engine revs,
The car seems to drive fine now and has plenty of power, no shakes unless i'm sitting at trafic lights idling or parked up with the engine running, It doesnt smoke and i'm getting very good economy out of it so i just cant figure out why its shaking so badly on idle
Once thing i did notice was that the rubber in the engine mounts is getting quite old and starting to crack, and i sprayed some plusgas into the injector unions before refitting the pipework back on them so wondered it i might have affected the spray pattern once they have warmed up
Has anyone ever come across this sort of problem before?

Mosser · Post by **Mosser** » 22 Jul 2004, 04:12

Forgot to add that i seem to also have great difficulty starting my engine when its warm now, it starts instantly once its cooled right down, but if i stop to fill up with fuel, i turn the key and it takes about 10 seconds of cranking to get it to fire and i have to use full accelerator too,
I also noticed that when the engine is running, there are air bubbles going into the injector pump, not sure if these would be affecting anything though?

Post by **RichardW** » 22 Jul 2004, 17:04

The air bubbles will certainly affect it - if it overheated you may have warped the plastic fuel filter housing letting air in when it warms up. Other thing I can think of is that the cam belt has not gone back on right, and the injection pump is a tooth out - that will cause all sorts of odd faults, but I would have expected them to be present hot or cold.

Plodder · Post by **Plodder** » 23 Jul 2004, 18:36

My 1997 406 suffers the annoying 'wobble' at tickover.
I think it is down to the lower engine mount, there appears to bit more play in the bush than I would like but I just haven't got around to doing anything about it yet...

Mosser · Post by **Mosser** » 23 Jul 2004, 21:11

Thanks for the replies,
I have triple checked the cam belt by putting the locating pegs in the flwheel and the injector pump and the cam sprocket and they all line up perfectly so i dont think i'm a tooth out,
It could be the lower mount i suppose, but i am now leaning more towards the injector spray pattern or opening pressure being wrong on one of the injectors, I will warm it up at the weekend and when its gone into its massage mode i will slacken the injector nuts slightly to see if one of the cylinders isnt firing properly due to no fuel being injected

JohnD · Post by **JohnD** » 23 Jul 2004, 23:20

If you can see air bubbles in the pipework, when you switch off they're going to collect somewhere and it ain't going to assist in starting. I would trace where they are coming from.

Mosser · Post by **Mosser** » 24 Jul 2004, 01:08

Trouble is that if i let the car cool down for about 4 hours then it actually starts first time, it only has the problem when its hot, i dont think its possible for the bubbles to dissapear once its cooled down is it ?

Paul 123 · Post by **Paul 123** » 26 Jul 2004, 17:33

A few years back now I owned a 405 diesel saloon that had covered over 350k. The engine mounts on that were worn but it would wobble from the start, not after it had warmed up. If it is engine mountings its most notable when you try to accelerate as the torque produced tries to rotate the engine as well as the wheels. Mine was so bad all you coud do was back off the accerator and try again very gently.
Paul

Mosser · Post by **Mosser** » 26 Jul 2004, 17:41

Thanks,
Sounds like the injectors then, I didnt get a chance to undo each union in turn to see if the problem was an injector one, but i've just remembered i have got 4 spare injectors in the garage !!, only trouble is that i dont have a spare one with a lift sensor in, so i will change them over one at a time and see if the problem goes away by this method,
I'm not going to have this car for long now anyway as i have got a very nice Xantia that is running perfectly !

fastandfurryous · Post by **fastandfurryous** » 04 Aug 2004, 17:26

Have you managed to cure the air bubbles in the fuel supply? I would have to say that this is probably the root of your problems. Aerated fuel can cause all manner of extremely strange running complaints (as I have found in the past) one of these is that when the engine is not run for a while, the fuel in the pump is not aerated, so the car starts just fine. After running for a while, the fuel becomes aerated, and will cause poor injection pattens, bad starting, lower idle speed, etc etc.. sound familiar?
David.