Ok I hadn't seen this , I will need to check again ..thanks for the pointer
Wont start. Fuel pump/relay
- Thread starter Tmmo
- Start date
Had another look for leaks , apart from what looks like dirt and muck within the engine bay there doesn't appears to be any obvious sign of diesel or oil leaking... On the last MOT there was an oil leak advisory. The dipstick level is just up to max on level . Not sure if my A2s dipstick is ok though as it looks as though bit of the bottom.may be missing. The only sign of any oil , or leak is on what looks like a mounting for hoisting the engine it's at the back just behind and more central than the tandem pump... It looks like this is aligned to what looks like a oil filler cap
DaveySprocket
A2OC Donor
That is not enough to be sure that it is clean, I found this out the hard way. It may not be the issue, but until you have totally stripped it down you can't be sure. I eventually found a little blob of muck stuck in mine, hiding away out of sight.No I haven't.taken it apart , I fired brake cleaner.through it at every opening I could find....maybe I will revisit this also and thanks
Ok I need to revisit .. it looks very fragile to take apart, does it just all unclip or is there a method to dismantling it and not breaking it in the process
Yes the pick up is within the sender unit and it looks like you have taken care of that.
If you look carefully there are arrows on the top of the fuel sender unit which tell you which is supply and return. The return has a NRV within the sender unit.
The timing will likely be ok if the belt has not been touched recently. I was thinking of a case where the belt HAD been replaced recently and the timing not set correctly afterwards. If the timing belt were snapped then I think you would notice as it would not turn over on the starter due to pistons hitting valves.
Yes I agree, easy start would fire it up and then it would die with air in the injectors. With easy start you are fuelling the cylinders via the air intake, not the injectors. I don't think it would run long enough to self bleed the injectors. In other words a successful easy start firing is not evidence that it's not a fuel issue caused by air.
One non fuel possibility that I have no experience of but have read about on these pages is a faulty injector relay. Maybe someone else might chime in on this? My bet is still on air in the fuel, though I have been wrong before!
If you look carefully there are arrows on the top of the fuel sender unit which tell you which is supply and return. The return has a NRV within the sender unit.
The timing will likely be ok if the belt has not been touched recently. I was thinking of a case where the belt HAD been replaced recently and the timing not set correctly afterwards. If the timing belt were snapped then I think you would notice as it would not turn over on the starter due to pistons hitting valves.
Yes I agree, easy start would fire it up and then it would die with air in the injectors. With easy start you are fuelling the cylinders via the air intake, not the injectors. I don't think it would run long enough to self bleed the injectors. In other words a successful easy start firing is not evidence that it's not a fuel issue caused by air.
One non fuel possibility that I have no experience of but have read about on these pages is a faulty injector relay. Maybe someone else might chime in on this? My bet is still on air in the fuel, though I have been wrong before!
DaveySprocket
A2OC Donor
I know what you mean, I did exactly the same as you, didn't take it fully apart the first time.. I was worried I would break something, but it's all tougher than it looks. Just gently ease things apart with a small screwdriver. You have to unclip the wires too, you can see a little lock tab on them the you need to push down to release them.
There are some photos on here:
1.4 Tdi Struggling to start..
Hello folks, I'm just getting stuck into finding out why my newly acquired A2 is having such a hard time starting, I changed the fuel filter first off, thinking it would be an easy fix, but it has made no difference at all. The problem does seem like it is fuel related, as in not enough fuel...
www.a2oc.net
Maybe I need to revisit cleaning, I have only flushed through and cleaned what I can visibly see as I havent taken the sender apart as suggested by @DaveySprocket in earlier reply
I know exactly the area you are describing. Oil leaks are common here. However if the tandem pump is leaking it can also dribble down this area. Check to be sure it is oil and not diesel dirtied from engine grime. and check it is dry directly under the tandem pump.
It seems to be dry directly beneath the pump, the pipe behind and the hoist bracket are caked in dirt though, the hoist bracket is wet it looks like oil , but quite possibly could be diesel also, all very tight under that intake box to be sure what is what , I will try to get a picture in the morning as light is fading now.
Oil in that area could be from the rocker cover, ASV valve or the rubber 'o'rings in the intake pipe being flattened. Non of that is serious in the short term. As long as it's dry under the tandem pump.
The main fuel feed connection to the tandem pump has always been a favourite. Because it gets hot from the engine/pump and obviously has diesel in it, it is particularly prone to going hard and losing it's seal. be really sure this connection is sound; prod it, poke it, try and twist it a bit, move the pipe side to side and up and down a bit while looking for cracks in the pipe or any movement on the spigot. "Air in" leaks can be very illusive.
The main fuel feed connection to the tandem pump has always been a favourite. Because it gets hot from the engine/pump and obviously has diesel in it, it is particularly prone to going hard and losing it's seal. be really sure this connection is sound; prod it, poke it, try and twist it a bit, move the pipe side to side and up and down a bit while looking for cracks in the pipe or any movement on the spigot. "Air in" leaks can be very illusive.
Is the main fuel feed on the back which I can barely get to ?
Early start ...
Frozen fingers and now a super clean sender ... All back together 
and still no start...
Schoolboy error question on my part but should I have clamped these lines to the sender before removing connectors and in so doing so have I introduced air ?Attachments
2work
Well Known Member
Morning Neil,
That’s even cleaner than before. Although it’s not resolved the non-starting issue it will have helped out on some way for sure.
When I’ve swapped the TDI fuel senders I’ve not clamped the fuel lines that connect to the top of the assembly. Never had starting issues afterwards either.
Kind regards,
Tom
That’s even cleaner than before. Although it’s not resolved the non-starting issue it will have helped out on some way for sure.
When I’ve swapped the TDI fuel senders I’ve not clamped the fuel lines that connect to the top of the assembly. Never had starting issues afterwards either.
Kind regards,
Tom
The fuel feed to the tandem pump is the higher connection, easily accessible. Connects to the upper of the two metal fuel rails running across the front of the engine.
Yes you will have introduced a bit of air, but as Tom says it will not be a problem because the air is so far away from the injectors. Once running the tandem pump will bleed this out without issue.Early start ...
2work
Well Known Member
Hi again Neil,
You probably know the following information but for the benefit of other other readers who take this task on in the future…
When replacing the fuel sender assembly you must ensure it’s correctly lined up. Looking at the top of the fuel sender assembly you’ll notice an arrow on the red circle below:
There will be a corresponding arrow on the fuel sender opening on the vehicle.
These arrows must be pointing at each other to ensure the float is correctly positioned in the tank so it doesn’t get stuck and of course reads the fuel level correctly.
Kind regards,
Tom
You probably know the following information but for the benefit of other other readers who take this task on in the future…
When replacing the fuel sender assembly you must ensure it’s correctly lined up. Looking at the top of the fuel sender assembly you’ll notice an arrow on the red circle below:
There will be a corresponding arrow on the fuel sender opening on the vehicle.
These arrows must be pointing at each other to ensure the float is correctly positioned in the tank so it doesn’t get stuck and of course reads the fuel level correctly.
Kind regards,
Tom
Looking at the two lines on the front of the engine which connect to the tandem all look sound except where the lower pipe, a rubber hose passes over some.conduit .. there feels like some abrasion on the rubber hose
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Thanks Tom, I hadn't seen the arrow on the tank but had aligned going on my pre removal photo. I can see in about a degree or two out
2work
Well Known Member
Hi Neil,
The arrow should be visible if the area is clean enough. You’ll have to apply a little downwards pressure to the fuel sender assembly so it doesn’t move when you’re fitting and tightening the locking ring.
Kind regards,
Tom
That top feed is a short piece of rubber hose and looks ok used a mirror , wiggled all seems ok , only the lower one seems to have any visible issue , where it crosses the conduit, but not.sure even with looking with a mirror.if it's holed. ... Can feel abrasion where it's clearly sat against the conduit but no visible leaks again...
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