Wont start. Fuel pump/relay

tnpali01 said:
Steady stream of bubbles in the clear pipe by
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Raining again 😧going to have to resume tomorrow 🤞... Need to charge battery so will leave it charging overnight, have another go tomorrow I hope.
TAABVW said:
Difficult to be sure at this stage. Keep sucking on it and crank it (easier with two people). Be prepared for it to start. If it starts that little tub will fill up with frothy fuel very quickly so don't get all excited at it starting, keep an eye on the tub so you switch it off before you get diesel in the vacuum pump workings. If it sounds like it's going to start and the tub is already quite full, it is prudent to stop and empty the tub into the fuel tank so when it starts you have an emptyish tub.

If you get that far then you are going to need some sort of connector to join the tub end of the clear tube to the rubber return line to the tank. You will then have a completed (sealed) return line with a plastic tube in it. Now restart and tickover until frothy bubbles clear. If they don't clear after about 10 minutes then you have air continually being drawn into the fuel feed and being bled out by the tandem pump. If the bubbles do clear, switch it off for a period of time (1hr - 1day) and repeat. If it doesn't start again or starts badly and you see froth in the clear tube again then you have an "air in" leak in the fuel supply system. If it starts fine (after standing overnight) and you see no air at all in the clear tube then the problem is elsewhere.
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The little tub is filling quite quickly, must have emptied it 10-15 times at around 3/4 full but still no start... theres still froth in the tub and lots of bubbles visible in the pipe. Assuming I should keep trying at least a bit longer. Unfortunately on my own doing this although I have sufficient reach to be able to operate the vacuum pump whilst cranking the ignition and watching over the tub.
 
Really interested in this as I'm going to attempt it tomorrow.
I suppose the question now in advance is where on earth would it be getting in?
I have read somewhere that near the cooler can be suspect.
 
johnyfartbox said:
Really interested in this as I'm going to attempt it tomorrow.
I suppose the question now in advance is where on earth would it be getting in?
I have read somewhere that near the cooler can be suspect.
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I'm hoping a bit more trying and it will clear the air, although I am resigned to it maybe an air leak, where , I have no idea and also how to trace an air in leak? possibly around the filter?? Wondering if the drain plug having attempted to remove it maybe a candidate, after that its needle in haystack , guess i need to look at the connections around the tandem and work back pre tandem to filter , filter to sender.
 
Cooler is in the return line. Any disturbed line increases the risk of non sealing and an air leak. The filter drain is THE prime candidate. Remember these fuel hoses are now getting old and increasingly less pliable so prone to cracking. The tandem connection on the input is also a prime candidate. You must ONLY use the correct type clips to ensure even clamping again to prevent leaks.
 
audifan said:
Cooler is in the return line. Any disturbed line increases the risk of non sealing and an air leak. The filter drain is THE prime candidate. Remember these fuel hoses are now getting old and increasingly less pliable so prone to cracking. The tandem connection on the input is also a prime candidate. You must ONLY use the correct type clips to ensure even clamping again to prevent leaks.
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I havent touched the return line except for where I have attached the vacuum pump. if its an air in leak on the feed, I guess one of the hoses I clamped could be culprit now , or the drain plug.
 
Next steps :
1. Try the vacuum pump for a bit longer and see if it will clear / start
2. Check feed line tandem connections , pre tandem to filter , filter to sender
3. Dremmel around the lip of the existing drain plug - remove the filter housing lid
4. Purchase deproman drain screw
5. New filter/ filter housing
 
OK. It sounds like you have done enough to confidently conclude that the problem is a reasonably large air leak in the fuel supply line. This is a positive step as at least you are not wondering anymore. You also know how to get it started after you've fixed it.
I agree the filter housing needs to get sorted first as it's a known problem and prime candidate.
 
Though I've never done this, I was just musing whether it would be possible to slightly pressurise the supply line with a bike pump. You'd have to block up the feed at the tank somehow.
I'm sure you can see my thinking in terms of confirming the leak point.
 
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Ok peeps.
I removed the feed back pipe from the metal pipe and just connected a see through pipe to the return pipe and cracked the engine over, good battery by the way.
Lowring the said pipe into a fill can.
After a few cranks I could see the fuel being pumped into the clear pipe but could see bubbles and froth, pictures here.
PXL_20240318_112126974.jpg
PXL_20240318_112239224.jpg






So This says to me that the fuel is getting through the tandem and is returning back to the tank .

Obs I have air in the system and Im still trying to find out where from, but my other problem is , the car WILL not start at all, no matter how much I crank it.
I think it might be an idea if admin could merge mine and Neil's problem into a dedicated thread with a suitable title.

PXL_20240318_112331725.jpg
 
@johnyfartbox in the picture of the clear hose the diesel to bubbles rario is enough to supply the injectors with the require diesel to inject and make a decent spray pattern in the cylinder bore. AFAIK.

You could remove the 3 glow plugs and crank the engine to see what gets ejected, atomised fuel I hope👍.

That should indicate the injector loom is doing its job and the diesel supply the injectors are receiving will make them activate.

A none starting engine all other factors being functional would point to the crank position sensor.

I read you have replaced your cam position sensor. I only got to page 5 of your non starting thread so do forgive me if you already installed a new crank position sensor.

You could check the cam position sensor is fitted securely by removing it, cleaning and refitting. That will cross another variable off the list. :)👍

All the very best of luck
 
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Thanks.
I did indeed change the cam sensor but after checking VCDS it registered a fault with it so put the original back in and no fault found.
I have a brand new crankshaft sensor but I can't get the car up on the ramps to do the swap from underneath the car.
 
If you have air in the injectors and have not applied vacuum on the fuel return then it will not start.
All the self bleeding is done by the tandem pump. If air has got past the tandem pump to the injectors then they will not self bleed. I thiink what you are seeing in the clear tube is the air being bled out of the fuel feed by the tandem pump. What you are not seeing is the air out of the injectors. The latter is frothy
 
johnyfartbox said:
Thanks.
I did indeed change the cam sensor but after checking VCDS it registered a fault with it so put the original back in and no fault found.
I have a brand new crankshaft sensor but I can't get the car up on the ramps to do the swap from underneath the car.
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If the rev counter registers when cranking crankshaft sensor is, probably, OK. Rev counter is driven by the crank sensor.
If you have registered Lite, or full VCDS, logging any group, while cranking, that includes engine speed, such as 001, will confirm it.
Mac.
 
PlasticMac said:
If the rev counter registers when cranking crankshaft sensor is, probably, OK. Rev counter is driven by the crank sensor.
If you have registered Lite, or full VCDS, logging any group, while cranking, that includes engine speed, such as 001, will confirm it.
Mac.
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Ahh, I'd forgotten about that, the rev counter does indeed move when cranking.
You might have saved me a lot of hassle reminding me, I'll just check again.
 
@johnyfartbox
I repeat what I said above. You may check the injectors are firing if you remove the glow plugs and watch for atomised fuel being ejected from the glow plug orifice.
Good luck sir, I do hope you find fuel
 
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