200tdi Lumpy Idle

Hello,

I am still having a slight problem with my 200tdi. It drives absolutely fine and has bags of power with no smoke, but it seems to idle erratically. There are no obvious leaks in the fuel line, it's all been replaced although I am still getting a lot of air in my fuel filter. In fact, when I removed my fuel filter yesterday, I noticed that the central channel was almost dry. It idles rough hot and cold, although sometimes it is absolutely fine. The lift pump is working fine. Would a little water in my fuel cause this? And why is my filter always next to empty?

Thanks,
-Tom

My filter was almost empty when I changed it. I think that's normal. I poured a full bottle of injector cleaner into it and it didn't fill it so it takes a lot.

When ye were doin' stuff before pos, did ye change all the copper washers around the filter housing?
it might be that ye're getting air in through them some how or the pipe from the lift pump isnt seated right

fit a clear plastic pipe in the line between pump and filter if bubbles find air leak if not dont worry about it,fuel is sucked from tank obvious places are sedimenter near outrigger or unions

khaos said:

My filter was almost empty when I changed it. I think that's normal. I poured a full bottle of injector cleaner into it and it didn't fill it so it takes a lot.

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It's not normal for the fuel filter to be empty, the central channel should be filled to the brim unless the non return valve has failed in the lift pump. Even then, there would need to be a leak somewhere further along the fuel line which would allow air back into the lines. It used to be full to the extent that it would pour out of the filter when I unscrewed it a few months back

bustersbus said:

When ye were doin' stuff before pos, did ye change all the copper washers around the filter housing?
it might be that ye're getting air in through them some how or the pipe from the lift pump isnt seated right

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I have been wondering about the filter head myself. It had two new copper washers on the inlet banjo from the lift pump but not on the bleed bolt, the blanking bolt or the pipe to the injection pump. As for the pipe from the lift pump to the filter housing, I like this idea. I have a spare part in the shed which I might be able to make fit. The tank to lift pump pipe is fine though, I can see the wear on the olive where it has seated.

jamesmartin said:

fit a clear plastic pipe in the line between pump and filter if bubbles find air leak if not dont worry about it,fuel is sucked from tank obvious places are sedimenter near outrigger or unions

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I've tried that and there is no sign of air in the fuel although there is plenty in the filter housing, which would point to a problem at the filter head it's self I expect. I haven't got a sedimenter fitted.

pos said:

I have been wondering about the filter head myself. It had two new copper washers on the inlet banjo from the lift pump but not on the bleed bolt, the blanking bolt or the pipe to the injection pump. As for the pipe from the lift pump to the filter housing, I like this idea. I have a spare part in the shed which I might be able to make fit. The tank to lift pump pipe is fine though, I can see the wear on the olive where it has seated.

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Change the washer on the bleed bolt and see if that makes a difference mate Another thing to consider is the olives on the other pipes too. These can get worn and are best replaced when removing pipes like the ones going to / coming from the lift pump and the one for the return pipe from the injection pump if ye've had that off anaw

bustersbus said:

Change the washers on the bleed bolt and see if that makes a difference mate Another thing to consider is the olives on the other pipes too. These can get worn and are best replaced when removing pipes like the ones going to / coming from the lift pump and the one for the return pipe from the injection pump if ye've had that off anaw

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I shall have a good look at them tomorrow. The banjo on the return from my pump has nice new copper washers it's just a pain in the arse trying to track down an air leak. Strange how it doesn't happen all of the time too.

pos said:

I shall have a good look at them tomorrow. The banjo on the return from my pump has nice new copper washers it's just a pain in the arse trying to track down an air leak. Strange how it doesn't happen all of the time too.

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Just found some photies from a guide ah should've done ages ago doh: ) to give ye an idea about the olive and washers etc (hope it makes sense mate)...















It's a wee bit late and ah've came back up the road from Cornwall tonight, but it might help towards finding that leak IF it isn't coming from the filter housing

bustersbus said:

Just found some photies from a guide ah should've done ages ago doh: ) to give ye an idea about the olive and washers etc (hope it makes sense mate)...

It's a wee bit late and ah've came back up the road from Cornwall tonight, but it might help towards finding that leak IF it isn't coming from the filter housing

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Cheers Buster, good photos. Well that lovely coupling that you have there is non existant on my setup. I just have a length of fuel hose sleeved over the length of metal pipe from the return banjo, to the nylon pipe that goes back to my fuel tank. I had them apart the other day and I could barely separate them so I doubt air is getting in there. Technically that line is under pressure though, so if any air could get in, surely it would be washed down stream back to my tank when the engine is running? It would certainly works its way up when the engine is off though I guess.

and bloody hell, you've gone diagonally up the UK! How long did that take you?

pos said:

Cheers Buster, good photos. Well that lovely coupling that you have there is non existant on my setup. I just have a length of fuel hose sleeved over the length of metal pipe from the return banjo, to the nylon pipe that goes back to my fuel tank. I had them apart the other day and I could barely separate them so I doubt air is getting in there. Technically that line is under pressure though, so if any air could get in, surely it would be washed down stream back to my tank when the engine is running? It would certainly works its way up when the engine is off though I guess.

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Ah'm not sayin' it is mate...but that "might" be part of yer problem (?). The pipe ye've got might feel tight but seein' as it's a compression joint on mine might say summit....

pos said:

and bloody hell, you've gone diagonally up the UK! How long did that take you?

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Diagonally? Nah, it was just over to the right, straight up and turn left... 500 miles

bustersbus said:

Ah'm not sayin' it is mate...but that "might" be part of yer problem (?). The pipe ye've got might feel tight but seein' as it's a compression joint on mine might say summit....

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All very true What a total bugger of a thing though. I've been hunting for air leaks for months!

bustersbus said:

Diagonally? Nah, it was just over to the right, straight up and turn left... 500 miles

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Haha, did you go in the bus? How did it perform?

pos said:

Haha, did you go in the bus? How did it perform?

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Didn't take the bus this year mate, took the mrs' puddle jumper although it must be said, we did it in about 8 hours compaired tae the 12 hrs in the bus!
Took the bus down a couple of times before and it never missed a beat
Luckily this year, there's very limited parking near the cottage and the only space that was available was the size of the mrs' car

bustersbus said:

Didn't take the bus this year mate, took the mrs' puddle jumper although it must be said, we did it in about 8 hours compaired tae the 12 hrs in the bus!
Took the bus down a couple of times before and it never missed a beat
Luckily this year, there's very limited parking near the cottage and the only space that was available was the size of the mrs' car

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Well there you go. I suppose with the Bus, you could have slept in it though which adds to the fun. I saw a few of your photos a while back with the mattress in the back Right off to sleep now, got to get up early in the morning to service my sisters Corsa

Night night,
-Tom

pos said:

Well there you go. I suppose with the Bus, you could have slept in it though which adds to the fun. I saw a few of your photos a while back with the mattress in the back Right off to sleep now, got to get up early in the morning to service my sisters Corsa

Night night,
-Tom

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Aye, we could've slept in the back of the bus... but it's a hell of a loooong walk back from the pub!!
It's nice just tae crash in a cottage with all the luxuries at this time o' year tho'..... feck! ah must be gettin' old (or spoilt)
Anyways, catch ye later mate

I just thought that I would update people on my bizarre 200tdi fluctuating idle problem. I have now completely overhauled the entire fuel system, from the pickup pipe in the fuel tank, through the fuel lines, lift pump, filter head, filter, injectors, spill rail and the injection pump. The only part of the fuel line that I have not replaced is the return line between the injection pump banjo and the fuel tank. I do know that this line is clear however, because I blew down it with an airline a month back. The small mesh filter in the banjo bolt into the return port at the back of the injection pump is clear, with no gunk or buildup. The only thing left on my mind with regards to the return line, is a piece of rubber hose that I have used to sleeve two nylon pipes (where I had to splice the return line when fitting the 200tdi). It is possible that the jubilee clip around the rubber pipe, has crushed or flattened the nylon inner pipe, preventing return flow, which would create pressure inside the injection pump. Could this effect the retard / advance mechanism inside the pump if the return line has a slight restriction?

Generally speaking however, the idle is now much steadier, and my 90 is not rocking from side to side like a Detroit ([nomedia="http://www.youtube.com/watch?v=SSU_7DqNJJY"]YouTube - GM Detroit Diesel 6-71 Cold Start, Idle Rolling (Hunting), Walk-Around, Rocker Action[/nomedia]). I have noticed however, (and this potentially opens up an entirely new kettle of fish), that the idle only drops and starts 'bobbling around' when a load is put on the engine. I do have an earth fault somewhere - pressing the brake pedal illuminates my sidelights and a few bulbs in my dash. Is it possible that the 12V feed to my stop solenoid is also being effected, causing the solenoid to 'twinge'?.

Also, if I rev and hold the engine, to maintain a slightly higher idle than standard, I can hear the revs fluctuating in a smooth, repetitive manner, from low to high (there is a pattern):

_ _ _ _ _ _ - - - - - - _ _ _ _ _ _ - - - - - -


What the hell does all this mean!?

Thanks
-Tom