1.4 Tdi Struggling to start..

@rotifer I no longer buy VAG clips. I get a spec and part number here, https://mikalorcompany.com/ .

This may be the clip you and I will be looking for but I wouldn't commit without measuring pipes

Audi clip.jpg


I then search for an online supplier, I usually find them on eBay but not on this occasion.

Audi clip 2.jpg


I don't know if this is the correct clip or what P&P will cost but with the number I need I think I will save a few £.

One of the reservations I have about this job is that the pipe is likely to have lost its elasticity under the clip and replacing clips will introduce leaks and cause starting problems.

Edit, I see you have already discovered Mikalor, I'll leave this post, may help others.
 
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Little Dog said:
@rotifer I no longer buy VAG clips. I get a spec and part number here, https://mikalorcompany.com/ .

This may be the clip you and I will be looking for but I wouldn't commit without measuring pipes

View attachment 122048

I then search for an online supplier, I usually find them on eBay but not on this occasion.

View attachment 122047

I don't know if this is the correct clip or what P&P will cost but with the number I need I think I will save a few £.

One of the reservations I have about this job is that the pipe is likely to have lost its elasticity under the clip and replacing clips will introduce leaks and cause starting problems.

Edit, I see you have already discovered Mikalor, I'll leave this post, may help others.
Click to expand...
Actually, they might be a better quality product, I bought a mixture of different sizes, most I probably won't have use for .
They were cheap so probably not the same quality as those in your link
 
johnyfartbox said:
Actually, they might be a better quality product, I bought a mixture of different sizes, most I probably won't have use for .
They were cheap so probably not the same quality as those in your link
Click to expand...
Do you have a box of these?

Clips.JPG


I use these if I can't get hold of Mikalor. Mikalor are better quality, I've never had on break when fitting. The clips above are prone to breakage.
 
johnyfartbox said:
Try parking facing uphill, I found that gravity will either slow run back or help run back.
Click to expand...
I don't think the diesel runs back unless there is a leak that lets air in. Not entirely certain yet as I don't fully understand the tandem pump but it seems to me diesel will not be able to run back.
 
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Little Dog said:
I don't think the diesel runs back unless there is a leak that lets air in. Not entirely certain yet as I don't fully understand the tandem pump but it seems to me diesel will be able to run back.
Click to expand...
Air has to get in, somewhere, for the feed line to empty back to the tank.
The path from the inlet, at the swill pot, (as long as there's fuel in it), right through the pump, to the injectors is, (should be), sealed. No leak, and the line will remain full. If the fuel in the line cools enough to shrink a bit, then fresh fuel will be drawn in from the swill pot.
The only potential path I can see, for air to enter, in a sealed system, is via the return line, if the non-return valve, in the tandem pump failed. But the return line would have to drain too.
I can't see fuel flowing through the pump from the pressure side to the suction side, in sufficient volume to empty the return line, via the feed, back to the tank, to allow air to get to the return port on the pump. If that did happen, then air will easily pass through the pump. Seems unlikely to me, but so does everything else!
If the return line could be closed off somehow, that would rule it in or out.
How does the return line terminate in the sender assembly? Is there a check valve, so return is only open when under pressure? If so, and that failed, the return line would empty quite quickly, and air would get to the pump.
Please read carefully, I'm not sure about what I've just written, now I've written it.
Mac.
 
PlasticMac said:
Air has to get in, somewhere, for the feed line to empty back to the tank.
The path from the inlet, at the swill pot, (as long as there's fuel in it), right through the pump, to the injectors is, (should be), sealed. No leak, and the line will remain full. If the fuel in the line cools enough to shrink a bit, then fresh fuel will be drawn in from the swill pot.
The only potential path I can see, for air to enter, in a sealed system, is via the return line, if the non-return valve, in the tandem pump failed. But the return line would have to drain too.
I can't see fuel flowing through the pump from the pressure side to the suction side, in sufficient volume to empty the return line, via the feed, back to the tank, to allow air to get to the return port on the pump. If that did happen, then air will easily pass through the pump. Seems unlikely to me, but so does everything else!
If the return line could be closed off somehow, that would rule it in or out.
How does the return line terminate in the sender assembly? Is there a check valve, so return is only open when under pressure? If so, and that failed, the return line would empty quite quickly, and air would get to the pump.
Please read carefully, I'm not sure about what I've just written, now I've written it.
Mac.
Click to expand...
I’m in agreement with that. Shame I missed a not out of my post 🤡
 
PlasticMac said:
Air has to get in, somewhere, for the feed line to empty back to the tank.
The path from the inlet, at the swill pot, (as long as there's fuel in it), right through the pump, to the injectors is, (should be), sealed. No leak, and the line will remain full. If the fuel in the line cools enough to shrink a bit, then fresh fuel will be drawn in from the swill pot.
The only potential path I can see, for air to enter, in a sealed system, is via the return line, if the non-return valve, in the tandem pump failed. But the return line would have to drain too.
I can't see fuel flowing through the pump from the pressure side to the suction side, in sufficient volume to empty the return line, via the feed, back to the tank, to allow air to get to the return port on the pump. If that did happen, then air will easily pass through the pump. Seems unlikely to me, but so does everything else!
If the return line could be closed off somehow, that would rule it in or out.
How does the return line terminate in the sender assembly? Is there a check valve, so return is only open when under pressure? If so, and that failed, the return line would empty quite quickly, and air would get to the pump.
Please read carefully, I'm not sure about what I've just written, now I've written it.
Mac.
Click to expand...
There is a one way valve in the return pipe on the sender, I am sure of that!
 
I just dropped mine off the blocks and then started it, she fired on the button.

So I put some clear pipe in the return line and started her again. There was a whoosh of air bubbles through the pipe and then she ran clear, with the occasional tiny bubble passing through. Just as I thought that she was going to stay clear, suddenly the fuel in the return line turned white and stayed like that until I shut the engine off. Then it settled back to clear fuel.
IMG_20240408_141818_HDR.jpg

I've put the front end up on ramps now, so will wait for a while and see how she starts like that.. 🤔
 
I'm hoping that that is just what hot diesel thats been diverted all over the place through meshes and tiny passageways looks like ;)
 
So after not much more than an hour with the front wheels on ramps, I tried to start her and she wouldn't start.. Aaaaaarrrggggg :eek:

Unbelievabubble, and curiously, the same thing happens to Mr Fartbox.. 🤔
 
DaveySprocket said:
I just dropped mine off the blocks and then started it, she fired on the button.

So I put some clear pipe in the return line and started her again. There was a whoosh of air bubbles through the pipe and then she ran clear, with the occasional tiny bubble passing through. Just as I thought that she was going to stay clear, suddenly the fuel in the return line turned white and stayed like that until I shut the engine off. Then it settled back to clear fuel.View attachment 122068
I've put the front end up on ramps now, so will wait for a while and see how she starts like that.. 🤔
Click to expand...
Given the volume of white stuff, it must be coming from the tank, or, at least the line to it. Maybe the filter? Looks almost like an emulsion.
Mac.
 
PlasticMac said:
Any idea where abouts? Tank end would be my guess ...
Mac.
Click to expand...
Sorry Mac, I should have been clearer, it's within the sender unit itself. The return connection on the sender is a plastic tube that goes back into the swirl pot, and the non return valve is in that pipe.
 
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