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Potential injection pump noise


reb78

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I've got a noise coming from the engine on my 200tdi. I associate it with the injection pump because the more I out my foot down to increase load, the intensity and volume of the noise increases. It also increases with engine revs. It's not really noticeable at idle and you can't hear it at higher revs.

It's hard to describe. It's a very fast ticking I suppose. I guess it sounds a bit like a cricket, or a field full of frogs!

Any ideas. Folks also say vacuum pump on the 300tdi, is this likely or does it sound like the FIP?

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Performance seems ok. Perhaps a little less top end than normal, but that can vary with the wind direction!

I have a spare vac pump from my old TD engine - i think they are the same part?? Only thing i dont have is the gasket for it - will a bit of RTV do the job there withough any issue?

I guess i may as well replace the filter as a matter of course, and perhaps lift pump if the vac pump doesnt sort it and/or there are no holes in the pipe to the servo.

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If the noise is definitely from the injector pump I would be thinking fuel starvation. If the lift pump is not working properly then the injector pump has to work harder to get fuel and this can cause it to tick or knock. Mine ticked a lot and sounded like a chicken 'bokking' when I turned the engine off. Then the lift pump gave out completely and I had to limp home. Replaced the lift pump and all was well in the world.

If the lift pump is old or original I would change this with a good quality Delphi one and then see if the noise goes away.

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If the noise is definitely from the injector pump I would be thinking fuel starvation. If the lift pump is not working properly then the injector pump has to work harder to get fuel and this can cause it to tick or knock. Mine ticked a lot and sounded like a chicken 'bokking' when I turned the engine off. Then the lift pump gave out completely and I had to limp home. Replaced the lift pump and all was well in the world.

This noise is from the lift pump. If, for whatever reason (clogged filter, clogged inlet line, old/shagged) the arm is unable to fully return then the cam hits it on the next round causing a 'tick' noise.

The weird chicken noise I've heard too - made as the arm returns to the cam making strange noises as the diaphragm sucks in air in my case due to a clogged inlet pipe.

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Ok,

I;ve tried to get a video of the noise. I'm not sure it is that clear, but it is the higher pitched noise you can hear for the first half of the video fairly easily. I got stuck behind some slower cars in the second half, so its less noticeable then unless I accelerate.

th_VIDEO0006_zpscb63d761.jpg

Any more ideas??

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Changed the fuel filter this morning. (Was going to do the engine mounts, but it's horrid out there!)

I slackened the bleed screw on top of the filter and started the engine like I normally do and it took an age to fill, even with mild revs on the engine to speed things up. I don't think I'm imagining the time to fill, it must have been 4 minutes before I got bubbles of diesel out of the top of the filter. Anyone else think this is long and potentially pointing to a knackered lift pump?

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Yes. I had a failed lift pump on my 300Tdi earlier this year, and after replacement the filter filled in way less than a minute. I'd had to remove injector pipes to get access to the pump, and they were bled, as well as the filter filled, in no more than a minute. I was mopping up diesel from all over the side of the engine in no time.

I don't know if the lever on the outside of the pump is supposed to allow you to operate it manually, but I had no joy trying this on the newly fitted pump. Perhaps I didn't try hard enough, not wanting to FUBAR something while I was still 3,000km north of home base - yes, Canada is BIG! I had to crank the engine to draw the fuel through and it fired-up after just a few seconds. On the new pump that I had just fitted the operating lever that goes inside the engine was quite difficult to operate, whereas on the old pump it almost flopped back and forward. I assume this because of the failure mode, but I didn't do a post mortem on the failed unit.

Mike

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  • 3 weeks later...

I'm still struggling with this. I've replaced the filter and lift pump, but the noise is still there.

Vacuum pump perhaps?

The other thing that seems to be suggested on searches is the exhaust manifold gasket. One thing I have noticed is that there is a puff of exhaust from the join in the bulkhead end of the exhaust manifold itself. I think these are interference fits rather than welded, but could this potentially be causing this noise and what could I do to fix it? Is it new manifold?

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