1.4 Tdi Struggling to start..

Before removing the OS engine mount remove the turbo outlet air pipe support bracket from the sump. If yours is broken or missing then someone did not do so before a cam belt change!

If this bracket is broken or missing the stress is now all on the lower intercooler end cap which will end up cracking and spitting out the seal an limp mode follows from there....
 
audifan said:
Before removing the OS engine mount remove the turbo outlet air pipe support bracket from the sump. If yours is broken or missing then someone did not do so before a cam belt change!

If this bracket is broken or missing the stress is now all on the lower intercooler end cap which will end up cracking and spitting out the seal an limp mode follows from there....
Click to expand...
A few days ago I was sat with my BIL looking at his Rickman Ranger which has a 1.4 tdi engine. The sump sticks out the bottom of the car and is clearly visible, we were looking at it wondering what the broken plastic bit was on the bottom.. 🤔

Yesterday I stripped down my spare engine and noticed the same broken plastic bit on the sump.. I think I know what it is now!

Thanks for the tip @audifan :)
 
DaveySprocket said:
A few days ago I was sat with my BIL looking at his Rickman Ranger which has a 1.4 tdi engine. The sump sticks out the bottom of the car and is clearly visible, we were looking at it wondering what the broken plastic bit was on the bottom..

Yesterday I stripped down my spare engine and noticed the same broken plastic bit on the sump.. I think I know what it is now!

Thanks for the tip @audifan :)
Click to expand...

And if you want a replacement lower turbo pipe clamp I manufacture these as no longer available form Audi


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I was still determined to get this car started again, so I tried again today with a recharged battery. I bled the inlet to the pump and there was loads of air in that line, then I bled the return and there was loads of air in it too. So I cranked away and after about 50 seconds cranking it did fire up and run. I managed to stop myself from revving it this time, so I just left it to idle, hoping it would sort itself out. It ran fairly rough for about 4 minutes and then stopped :eek:.

I've got a bit of clear pipe in the feed from the sender, and I could see in that there is air in the line. Of course that air could be getting into the sender via the return line. Either way there is too much air in the system for it to sort itself out, as hoped.

So I will leave it for now until I can get some help with it from my brother in law.
 
It would be good to know what the internal flow paths, and non return valves are within the sender. I'd be surprised if the point where air emerges from the return line is lower than the pickup. So return air shouldn't be the source of air in the feed.
I've felt for a while that the sender assembly is your root cause.
Mac.
 
PlasticMac said:
It would be good to know what the internal flow paths, and non return valves are within the sender. I'd be surprised if the point where air emerges from the return line is lower than the pickup. So return air shouldn't be the source of air in the feed.
I've felt for a while that the sender assembly is your root cause.
Mac.
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I switched senders back when I had the other car, and it made no difference to either car, one still ran perfectly, and the other didn't. For that reason I have been ruling out the sender, but I have also had them both stripped down to clean, so something could have gone awry maybe. I'll maybe see if I can set something up without the sender, just two pipes into the tank 🤔
 
DaveySprocket said:
I switched senders back when I had the other car, and it made no difference to either car, one still ran perfectly, and the other didn't. For that reason I have been ruling out the sender, but I have also had them both stripped down to clean, so something could have gone awry maybe. I'll maybe see if I can set something up without the sender, just two pipes into the tank 🤔
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I think I'm mixing up your car and Johny's.
Mac.
 
DaveySprocket said:
I was still determined to get this car started again, so I tried again today with a recharged battery. I bled the inlet to the pump and there was loads of air in that line, then I bled the return and there was loads of air in it too. So I cranked away and after about 50 seconds cranking it did fire up and run. I managed to stop myself from revving it this time, so I just left it to idle, hoping it would sort itself out. It ran fairly rough for about 4 minutes and then stopped :eek:.

I've got a bit of clear pipe in the feed from the sender, and I could see in that there is air in the line. Of course that air could be getting into the sender via the return line. Either way there is too much air in the system for it to sort itself out, as hoped.

So I will leave it for now until I can get some help with it from my brother in law.
Click to expand...
If you hang a can of diesel over the pump and feed it direct into the pump does it run until it empties the can? You would have to block the feed from the filter. You may also need a second can on the return side but I would try first returning the unused but pumped fuel back to tank.
 
DaveySprocket said:
I took the injectors out of my spare engine today, so I thought looking at them and where they go in the engine, might shed some light on how/if bad injector seals could let air into the fuel flow?

The hole near the top must be where fuel goes into the injector
View attachment 122905
In the head there are two holes, so I'm guessing one flow and one return.
View attachment 122906View attachment 122907
I suppose if that top O ring wasn't perfectly sealed then air could get in there?
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These injector seals are completely shot!
Looking at the orange O ring the sides are completely flat fit a set of seals to each Injector & try that , I think it will make a great improvement for minimum outlay
Hope that helps
Keith .
 
Little Dog said:
If you hang a can of diesel over the pump and feed it direct into the pump does it run until it empties the can? You would have to block the feed from the filter. You may also need a second can on the return side but I would try first returning the unused but pumped fuel back to tank.
Click to expand...
Yes it does that no problem, although I haven’t tried since I put the old pump back on..
 
kp 115 said:
These injector seals are completely shot!
Looking at the orange O ring the sides are completely flat fit a set of seals to each Injector & try that , I think it will make a great improvement for minimum outlay
Hope that helps
Keith .
Click to expand...
Thanks Keith, those are actually from my spare engine, but it is more than likely the injector seals are not good..
 
DaveySprocket said:
Yes it does that no problem, although I haven’t tried since I put the old pump back on..
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I would try again with the old pump. However I think you will conclude there is nothing wrong with the pump shaft seal. To double check have the pump draw diesel from ground level and squeeze the pipe to increase the negative pressure in the pump. That, if the engine runs, eliminates the pump from the list of suspects. I would be very surprised if it were the injector seals. But you could fit a clear return pipe and check. It may take a while to run clear of bubbles but that would exclude the injectors.
Main suspect would then be feed and return lines and the filter housing.
 
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