Morning Fellow Backroomers. Hope there are some suggestioons out there.
I changed my cambelt yesterday, all timing cogs marked up properly so as to keep the same position etc and when all was put together again with the new belt in place, the engine was started and the sound is not the same.
Normally a very smooth engine but now I have ticking from the fuel pump area. I suspect that I overtightened the tensioner so the fuel pump cog has moved slightly out of alignment. The engine now sounds like a Transit Van. The car drives OK, no problems there but power does seem a little down.
Any ideas if my thought is correct, if not does anyone have a potential cure / other ideas
Please do return for more information if needed.
Many thanks in advance.
Christopher
{Correct year entered using a forum search of previous posts relating to this car}
Edited by Dynamic Dave on 14/09/2009 at 13:34
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On a common rail diesel (I assume this is a dCi engine), the injection pump is not timed. Its role is only to generate the (astronomical) fuel pressure in the fuel rail. The actual injection timing is controlled by the ECU, by triggering the injectors at the appropriate time. Much like multipoint petrol injection systems work.
I would be checking in the area for loose bolts / covers / foreign objects where they shouldn't be. It's worth doing this sooner rather than later, as any foreign objects inside the timing belt cover could be disastrous news. I've dropped sockets, bolts and things into dark recesses without realising before - it's easily done.
Cheers
DP
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Thanks for that DP.
Just one point, the ticking noise raises and falls with the revs. Would this indicate that the cogs for the injection pump may not be inline?
Thanks
Christopher
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It's a little crude, but if you put your hand on the cover with the engine running, can you feel anything striking the cover in time with the noise, or anything to indicate contact? Were there any spacers on the cover mounts which got missed off on reassembly? Anything not line up easily when refitted? Is the cover tight? What else did you disturb to get to the belt - don't overlook the auxiliary belt, alternator, air con pump, engine mounts etc etc. Is everything tight and back where it should be?
Unfortunately, you're going to have to pop the covers off and have a good look. You really don't want the belt failing. Remember the belt relies on all the pulleys it engages with being correctly aligned and placed to maintain the correct tension. If a single pulley should move, seize or fail in some way, or if any foreign object should get caught up in the belt teeth, it could wreck the engine.
If I were you I would take the cover off, and if nothing os obviously amiss, run the engine and make sure the pulleys all run true, are tight, are in alignment, and that nothing is obviously amiss. If the noise stops with the cover off, you know something is striking the cover. Check the inside of the cover itself for marks - this may give you some clue. Also check the condition of the new belt very carefully. If it's been rubbing on something or has teeth damage, it will need changing again.
Good luck.
Edited by DP on 14/09/2009 at 16:41
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I don't really agree that it's plainly a mechanical noise of something dropped where it shouldn't have - the user complained of power loss too. The ignition timing has got nothing to do since as correctly pointed out the timing is not done by the pump but by the ECU according to cam / crank position sensors. Did you change the timing belt tensioner? That should be changed everytime with the belt and might be gone. Also, don't ask me why, sometimes water pumps fail with the timing belt. VW's sell you a whole kit including a water pump in fact! However what i suspect most is incorrect valve timing. Are you sure the dents and marks were all aligned? I fear the sound you are hearing is valves slightly striking pistons!
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