Rattle from engine on hard acceleration

[Welly]

I saw an HDi saloon today and it was even louder then mine, it sounded like a black cab!

It rattles at anything above idle 'til around 3k when the note changes to a more constant noise. Also, the more I tread on it the louder it is but it's there even at light throttle openings. I suppose it does sound a bit like a tappet but they usually don't stop at a particular engine speed, nor does a small end.

Mine's exactly the same. Bit nasty sounding actually

I very rarely go near 3000, more often I change gear just after 2000 - the most rattling occuring 2000 to 3000.

[muffindell]

Yeah, mine used to rattle (like tappet noise) til 3000rpm when it would stop dead and all was calm. The dealer said it was the second phase injection and loads had come in with the problem - except he said it wasn't actually a problem in everyday driving and would say it was 'normal'. I have to disagree saying that diesel engines dont like being reved above the max torque point, you will never achieve max BHP unless you rev it to about 4100, it also keeps the engine clean inside, kicking all the carbon out; you wont get problems with a sticking EGR valve if you use the full range either (keeps it working throughout the valve flap range)

[Welly]

I must admit I do drive for ecomomy mostly and drive on the torque only (if you know what I mean) and change gear at just over 2000 and always before 3000 - BUT every single day of the week it gets a full temperature "Italian Tune up" I consider this will force any crap out of the egg sauce manifold, EGR port, turbo turbine and CAT.

I don't rev the knackerz off it I just make sure it's fully boosting and pulling as hard as it can in 2nd, 3rd and maybe 4th.

[muffindell]

Guess I'm lucky, all my cars get a nice 1 mile hill climb every day, I overtake everything in sight, changing gear when I hit around 4300RPM, making a mental note of terminal speed at a road sign at the summit, if this is down by any amount then I know I have problems - it also gets rid of all the crap in the engine! The fuel computer usually hits around 13mpg when I do this!!

[Longintooth]

Hi
Well I would like to know more about this rattle some of you have experienced. I would not think it would be a cam follower sticking on an overhead cam but I have come across some on other engines that have cracks around the skirt and they have caused some noise which is louder on load but was always present. On larger diesels 6 - 16 litres most little ends are fully floating and they do sound off when worn but many are now going to clamped conrod with just the gudgeon floating in the piston - I can't say I've ever heard these rattle but for some reason they are more prone to piston slap but this is always present but louder on on light loads and you have a smokey blue exhaust. If I had this rattle I would certainly be trying to eliminate all obvious engine problems associated with wear rather than broken first. I assume that the clutch and dampers are all ok when this noise is present - you all know the demon dual mass flywheel probs. Get a hold of a stethascope to pinpoint the area. Oh and
the small high speed diesel will rev better than the heavies since the mass on the piston is lower but it's a diesel and they do compress a lot of air with a thump then bang the piston hard on th power stroke - just imagine how that little crankshaft will fair if you get those huge oscillating forces going at max revs - see how long it is before you have to change that DMF or front damper. On big diesels they have tough crankshafts
to take it but the mass on the piston is huge and the torque falls away rapidly, then you gotta change gear. Diesels are very clean running on the inside and do not gather rubbish inside because they run a little cooler and the carbon does not tend to burn onto valves etc as petrol and the nature of diesel fuel is excellent as a freeing agent - that's why they last much longer than a petrol so think again about the myth of giving it a good belting - it's not necessary. Just let it pull low down like a mighty shire horse.

[steve_earwig]

I meant an FX4.

I suppose your car's worth next to nothing Maybe it would be worth dropping a lump in from a breakers but then what else will go wrong? Or cutting your losses, scrapping it and buying a newer one and hoping nothing goes wrong... Devil, deep blue sea.

This sewing machine noise, does it change at just over 3k?

Well I would like to know more about this rattle some of you have experienced. I would not think it would be a cam follower sticking on an overhead cam but I have come across some on other engines that have cracks around the skirt and they have caused some noise which is louder on load but was always present. On larger diesels 6 - 16 litres most little ends are fully floating and they do sound off when worn but many are now going to clamped conrod with just the gudgeon floating in the piston - I can't say I've ever heard these rattle but for some reason they are more prone to piston slap but this is always present but louder on on light loads and you have a smokey blue exhaust.

So not piston slap. All our cars have exactly the same fault??

If I had this rattle I would certainly be trying to eliminate all obvious engine problems associated with wear rather than broken first.

New, cam, new valves, new sawn off shotgun...

Get a hold of a stethascope to pinpoint the area.

It only happens when the car's under load (i.e. driving) so maybe not that do-able. Anyone got access to a rolling road?

I've just been doing a screwdriver to ear job on mine, I can hear rattles around the injectors which is loudest on the fuel unions, it's on the head around them too but not as loud. Removing the 710 cap I can hear the cams doing their stuff but nothing gets any louder. I was revving it to over three grand and back while I was doing all this (and getting rather hot) but I couldn't find anything at all that changed pitch, frequency or anything

[puggy]

Yes i too get this rattle,and since the re map which lets it rev more
freely i regularly go over 3k . Pull off everything normal get to just over
2k and distinct change in engine sound (yes bit rattly ) after 3k gone
and stays that way to over 4k , and when doing around 80/90 very
quiet

[Longintooth]

Hi
You know it could be a fueling problem from what you are all saying, if this is more like a diesel knock up through the range when you simply rev up. I did discount this earlier because if it was there would be some grey to black smoke with it and none have mentioned this. I had to look at JCB 3CX that had developed a bad knock following a fuel filter change - it sounded off all the way up to max revs (almost like the crank had had it but it had smoke with it so checked the injectors and all had some spray holes with very poor atomisation. It appears that some muck had got into the system and worked its way up to the injectors. After servicing them it was fine. It's not the injector that knocks or rattles it's the fuel that is not combusting properly so you get the knock - similar to pinking in a petrol. Though these were a conventional inline pump injectors that get lifted with pressure the same could apply to common rail where they are piezo operated - this would worry me though. You can get away with some muck in an inline pump but a CR pump will not tolerate any for long (They could just be worn too) When changing fuel filters it should be with meticulous cleanliness - rubber gloves and everything cleaned off before starting - nothing should enter that bowl. I've seen this job given to young apprentices who on occasion have dropped the filter on the floor only to pick it up give it a blow and stick it in. it's hard to distinguish what someone calls a rattle for a knock but there is a subtle difference.

[steve_earwig]

Starting up this morning I noticed a fair bit of noise so I got my screwdriver out, loudest on the union on the injector for #1 cylinder.

When I first got this car it did seem much quieter than my 2.1 but then I was driving it like grandma. It then sat in my garage for 3 months (stupid registration tied up by my visa), during which time I serviced it, including changing the fuel filter - I didn't know about damaging the pump with a tiny bit of dust at the time - it all seemed fine 'til I went to register it, then the tappety/rattling noise became apparent. I'm still not sure if it was there before or I damaged something when I changed the filter.

[steve_earwig]

Oh sheep! I think that's your lift pump dying

[Longintooth]

Hello Steve,
No disrespect intended but the filter is in a very tight situation on the 406 110 and you have limited options to get it clean before taking the lid off - don't be tempted to use a pressure washer either. Use a degreaser with just the water tap pressure and keep all the electrical connections wrapped up. Give it a good wipe down with that blue hand wipe paper not cotton wipes both outside and inside the bowl. If you have got the rattle/knock it would be worth getting someone to follow you and observe the exhaust - if any smoke, grey or black, get the injectors changed since they will not clear without proper injection room equipment. Even if the pump has been scored with grit it may still be ok for a good while but the noise should stop. Just a word here on the injector pipes - they are intended for a once fit and tighten but I have reused successfully, however, I don't recommend. Make sure they fit without any bending, pushing, squeezing - they should be perfectly aligned without effort. They do not need to be bled like conventional injectors - the system will bleed itself. It is likely that this is common for the very reasons outlined earlier and make sure any pipe dampers are replaced in the same position. Oh and don't be tempted to connect an injector out of engine to check spray pattern - it is best to let an injection shop specialist check them or just buy new ones. The spray atomization is incredibly fine and difficult to see streaks which would cause the problem.

[Welly]

I am sure it's fuelling as it goes away after the magic 3000 mark.

Some of you might remember my usual mechanic more or less refused to change my fuel filter saying it had to be changed in almost laboratory conditions and he would have to sheet off the area (like a crime scene) and have negative pressure ventilation etc etc and mentioned something like anything as small as one tenth thickness of a human hair could screw the injectors/pump.

I was a bit miffed at this and went to peugeot (who appeared to take no special precautions to me) and sure enough I have the noisethe thing is the car drives well otherwise so I would be reluctant to embark on an expensive investigation such as replacing injectors on a car of this value

I bet every damn one of us (except longintooth) has had a filter changed in dubious conditions and maybe we're suffering as a result? maybe this is why some of us get 45mpg and other get 55mpg etc?

I suppose we should recommend having a new filter + housing each time to minimise exposure to dirt ingress.

[steve_earwig]

No disrespect intended but the filter is in a very tight situation on the 406 110 and you have limited options to get it clean before taking the lid off - don't be tempted to use a pressure washer either. Use a degreaser with just the water tap pressure and keep all the electrical connections wrapped up. Give it a good wipe down with that blue hand wipe paper not cotton wipes both outside and inside the bowl.

It was as clean as a new pin under there but I was very careful when I did it, I even used all the blanking plugs etc but I think the problem is that, once you take the filter out, anything that's dropped off the filter into the bowl has a 50/50 chance of ending up the wrong side of the new filter When it comes due I'm taking it to a specialist for a service, I sooooo don't want to touch it again!

If you have got the rattle/knock it would be worth getting someone to follow you and observe the exhaust - if any smoke, grey or black, get the injectors changed since they will not clear without proper injection room equipment.

They're £300 a pop!

Even if the pump has been scored with grit it may still be ok for a good while but the noise should stop.

Pump sounds fine with my magic screwdriver, quiet as a mouse.

Just a word here on the injector pipes - they are intended for a once fit and tighten but I have reused successfully, however, I don't recommend. Make sure they fit without any bending, pushing, squeezing - they should be perfectly aligned without effort.

I know. Won't be my problem anyway (see above)

Oh and don't be tempted to connect an injector out of engine to check spray pattern

Oh my eye, my eye!!!

- it is best to let an injection shop specialist check them or just buy new ones.

"just" buy new ones and now I'm getting noises from the front suspension If I could insure it for fire it'd be ablaze by now

[Longintooth]

Hi all
You have my sympathies since I was stung with that BSI and I have not taken my motors to anyone since I was apprenticed and qualified - they used to bring them to me - how times have changed. Just like all the other skilled craftsmen we have been replaced by computers. We have few engineers who can use a lathe, no core makers who made patterns it has become uneconomic to repair anything though I keep trying. My local
aftermarket garage have a yard full of really shiny motors that the owners have handed the keys over simply because they could not/would not pay the bill. I'm looking for an old merc with a distributor and twin carbs or a massy fergusson tractor (two seater) - sod the climate.

[Welly]

I was playing with my car last night and I could make this rattle go away!

3rd gear was best - accelerate through 2500 rpm and get the "rattle" then back off and on again a couple of times with the gas whilst maintaining your speed and then carry on up to 3000 rpm and it goes quiet

I suppose you're putting the injection on hold during the rattle and it must alter the fuelling enough to top the rattle

One thing I did notice though was my car seems to be schmoking quite a bit and my economy is slowly dropping although this isn't connected to the experiment above.