Suddenly won't start after recent tandem pump change

Ok, car had been stood since around 7.30 last night.
Key in, switched on,glow piug on then off, turned key and Engine turning over.
The battery is relatively new and holds change very well and spins the engine over with ease.
It took around 7 spins for the engine to fire up, not 7 attempts.
It kinda laboured for the fuel to finally take over and the engine to run smoothly.
Having now got a proper fuel line in place on the feed, I can no longer see if the fuel had run back creating an air gap but I suspect that would be the case just now.
 
johnyfartbox said:
Ok, car had been stood since around 7.30 last night.
Key in, switched on,glow piug on then off, turned key and Engine turning over.
The battery is relatively new and holds change very well and spins the engine over with ease.
It took around 7 spins for the engine to fire up, not 7 attempts.
It kinda laboured for the fuel to finally take over and the engine to run smoothly.
Having now got a proper fuel line in place on the feed, I can no longer see if the fuel had run back creating an air gap but I suspect that would be the case just now.
Click to expand...
Sounds correct, is it possible to fit a one way valve back down the line, tandem pump end. To see if it's in that section or the other side of the tandem pump,
I think I have mentioned it before when working in research and development we had an engine that had the same issue but intermittently. It proved to be that the engine would stop in one of three places by making up the flywheel. It was OK in two of them but in the third fuel would leak back and wouldn't start afterwards. It was a 6 cylinder engine by the way.
 
I have a one way check valve in the fuel line, and makes no improvement with the long starting times.. makes me think it doesn't hold enough fuel just in the line to get it started?
 
allypug said:
I have a one way check valve in the fuel line, and makes no improvement with the long starting times.. makes me think it doesn't hold enough fuel just in the line to get it started?
Click to expand...
How many other TDI's / engine /year of manufacture have / had this issue.
Anyone found a cure?
 
Could a faulty anti-shudder valve also be a cause of very long cranking time to start? my AMF TDi has a fair bit of oil leaking from it!
Read a few threads on here about them, and EGR valve which I have now disconnected and plugged the vacuum hose.. just as it's a very simple 'upgrade'!
Next time the car is left overnight, when starting it up, I'll hold the anti-shudder valve open by hand and get the missus to crank it over. Then I'll know for sure if it is the anti-wotsit valve or not causing the long starts.
 
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allypug said:
Could a faulty anti-shudder valve also be a cause of very long cranking time to start? my AMF TDi has a fair bit of oil leaking from it!
Click to expand...
The amf has a combine asv and egr, oil leaking from the front of the gr could be the oil escaping from the vent hole. This is a small hole used when the diagphrm inside the egr breaks. I would remove the egr asv unit and inspect and clean. A stuck open egr could give poor air quality for starting.
 
allypug said:
I have a one way check valve in the fuel line, and makes no improvement with the long starting times.. makes me think it doesn't hold enough fuel just in the line to get it started?
Click to expand...
If the line is draining back and air is entering, I'd put a check valve, (non return valve), as close to the tank as possible. Nearer the tank it is, the less air can enter and there should be enough fuel in the line, to get the engine running.
Mac.
 
PlasticMac said:
If the line is draining back and air is entering, I'd put a check valve, (non return valve), as close to the tank as possible. Nearer the tank it is, the less air can enter and there should be enough fuel in the line, to get the engine running.
Mac.
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Check valves rely on the head, (height/weight) of fuel above them to keep them closed when there is no flow. So, fitting one close to the pump is not going to help much.
As low, and as close to the tank is the best place.
Mac.
 
George Hogg said:
What clamps are you using?
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They are actually period correct for a 1968 Triumph Bonneville, but were the perfect size, and clamp more 'circular'
 

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Do not fit a check valve in the fuel feed line. If anything breaks off it as it is post the filter it will enter the pump and possibly damage or block the flow. Audi did not fit a check valve for a reason. Air in the system indicates a leak that needs fixing not masking with a check valve.
 
audifan said:
Do not fit a check valve in the fuel feed line. If anything breaks off it as it is post the filter it will enter the pump and possibly damage or block the flow. Audi did not fit a check valve for a reason. Air in the system indicates a leak that needs fixing not masking with a check valve.
Click to expand...
Where is the filter?
Mac.
 
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