200tdi - suddenly lacks power

tottot said:

He did say he had ordered a new filter but was it fitted?

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Alright - I am back fellas, with a complete non-update.

I ordered a lift pump and a filter. But then decided to cancel the lift pump and just go with the filter and a quick peek in the tank before getting a pump.

However, they canceled the filter order, and still sent me a pump. But this pump is wrong anyway. So, back to square one there.

I did look inside the tank today, and it's spotless in there, can't see anything in/near the dish that the pickup sits in that could cause any issues at all.

I will try again to order a new filter.

Also keep in mind that, while I haven't driven it any real distance since this happened on Sunday, it does seem to be running totally fine.

Hey guys - an update.

Went to get in it this morning to drive to work, and the problem has recurred. So far this doesn't happen during a drive, it will be like it when I start up and go to pull away.

Hopefully it stays in this condition until I have some time to investigate. I do have a new lift pump so that's my first target.

limeypete33 said:

Hey guys - an update.

Went to get in it this morning to drive to work, and the problem has recurred. So far this doesn't happen during a drive, it will be like it when I start up and go to pull away.

Hopefully it stays in this condition until I have some time to investigate. I do have a new lift pump so that's my first target.

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Defo sounds like air is getting in when parked for a period of time and thats why it has no power as its tries to self bleed.

lynall said:

Defo sounds like air is getting in when parked for a period of time and thats why it has no power as its tries to self bleed.

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Would that not cause difficulty starting? At the moment it starts right up, you would only realize there is an issue when you try and move and put it under load.

Also if you hold it in neutral and apply some revs, if you hold it there for a few seconds it will eventually struggle to maintain that level of rpm.

Air getting in overnight at filter or pump will result in motor starting fine but shortly after power is lost as air reaches injection pump. Depending on the amount of air getting in, if just a little injection pump will clear it and engine will pick up. More and it keeps going with power loss. Lots and it will not go.

tottot said:

Air getting in overnight at filter or pump will result in motor starting fine but shortly after power is lost as air reaches injection pump. Depending on the amount of air getting in, if just a little injection pump will clear it and engine will pick up. More and it keeps going with power loss. Lots and it will not go.

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Ok interesting...

Any recommendations on how to chase the air leak?

Change filter and lift pump.
I have a section of clear pipe just before my lift pump this makes it easy to check for air getting in from the tank/fuel pipe.

limeypete33 said:

Ok interesting...

Any recommendations on how to chase the air leak?

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Read my post from Monday about the air leak. I advised you then.

tottot said:

Change filter and lift pump.
I have a section of clear pipe just before my lift pump this makes it easy to check for air getting in from the tank/fuel pipe.

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That’s where I have mine too. It’s a pain in the arse to move though, as it’s so tight on the fittings. I carry some in my toolbox now....just in case.

For information
Supply pipes are 10mm outside diameter nylon tube.
You can get near clear nylon tube from pneumatic places cheaply.
ALL my pipes are clear nylon now but it's not a simple job, however, you can use 10mm compression fittings to splice a clear piece of tube in where ever you like.
The compression fittings are available everywhere and you don't need inserts for the tube I've found but use them if you can.
My local place was out of stock of them at the time so I didn't bother, no leaks or air engress in 16 yrs

Flossie said:

For information
Supply pipes are 10mm outside diameter nylon tube.
You can get near clear nylon tube from pneumatic places cheaply.
ALL my pipes are clear nylon now but it's not a simple job, however, you can use 10mm compression fittings to splice a clear piece of tube in where ever you like.
The compression fittings are available everywhere and you don't need inserts for the tube I've found but use them if you can.
My local place was out of stock of them at the time so I didn't bother, no leaks or air engress in 16 yrs

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I’m using 5/16 ID rubber fule line, for feed and return. I couldn’t be doing with nylon again.

Just put some clear into one leak off pipe, that will show you if air is getting to the injectors, but if it were it would spit and miss, it could be that the filter head none return isnt working and fuel is draining back, it could be a leak in the high pressure pump although this would also cause a miss and a spit, they have Bosch pumps dont they? Does it have a cold advance like the old CAV pumps? You really need to get your fuel pressure from the lift pump checked if you cant do it your self.
Diagnosing a fault without first running tests to locate it will result in you swapping out parts and if you arnt lucky enough to nail it first time it will start getting expensive and you still might not get to the bottom of it.

nobber said:

Just put some clear into one leak off pipe, that will show you if air is getting to the injectors, but if it were it would spit and miss, it could be that the filter head none return isnt working and fuel is draining back, it could be a leak in the high pressure pump although this would also cause a miss and a spit, they have Bosch pumps dont they? Does it have a cold advance like the old CAV pumps? You really need to get your fuel pressure from the lift pump checked if you cant do it your self.
Diagnosing a fault without first running tests to locate it will result in you swapping out parts and if you arnt lucky enough to nail it first time it will start getting expensive and you still might not get to the bottom of it.

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Tdi filter head is dead simple pipe in pipe out no valves.

So what stops drain back into the tank?

nobber said:

So what stops drain back into the tank?

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If no air getting in, fuel won't run back, because it would create a vacuum.

Nrv's on the lift pump too.

nobber said:

So what stops drain back into the tank?

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TBH I havent a clue, but its quite possibly the simplest fuel feed system ever, its literally tank, supply pipe, lift pump, filter, inj pump, Iirc leak off return tees into the inj pump return to tank pipe banjo fitting.

Flossie said:

Nrv's on the lift pump too.

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Two Iirc fromn the last time I stripped an old one and fitted new poppet valves, think it was a boat for a series one.

Hey Guys,

Update for you.
Since the pump and filter were both ready to drop in and I had some time yesterday, I decided to give it a go. Here is how it went down:
I wanted to see if it was running ok first, so I went for a quick drive. Started up fine and seemed to have torque. Drove it up the road and not even a mile from my house I lost power. I got it to limp home slowly. It really does feel like it's running out of fuel. Again leading to fuel pressure of some sort.
I got to work and replaced the lift pump and filter.
Started right up - took it for another short drive and this time no loss of power at all. I only had time for a quick 5 min drive but all seemed good.
This morning I went for a longer (probably 5-6 miles) with plenty of idling along the way and all the while there were no issues.

So far so good - I guess if it happens again then my next step is to swap out the lines for clear ones and track down an air ingress issue.

Thanks for all your help so far!