Wont start after fuel filter change

Disco Stu

Member
Hi guys,
Changed the fuel filter (paper element type) and after changing it wont start :(

After lots of turning over attempts it still wont start and now the low oil level warning is coming on. Have now flattest the battery and it is being jumped by the van.

I’m a bit lost on what to do now and even went to get a gallon of diesel!
 

drewroberts

A2OC Donor
Sounds like an Air lock in your fuel system. Need to bleed it all out. Someone with more knowledge will be along to help you shortly.
 

sco

A2OC Donor
Did you clamp the fuel lines - if not you've probably completely drained the system and it will take a while to re-prime. If you did clamp the lines - have you definitely removed all the clamps!

Simon.
 

Disco Stu

Member
I did think that but everything I have read says these are a self bleeding systems.
No I didn’t clamp the pipes - there is a lesson learned.
In fact it was stationary for two days as I hammed up the bleed screw that is made of cheese so I had to wait for a new one from Mr Depronman (which is a fine piece of engineering may I say, but more of that later)
 
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Pinkythelabrat

A2OC Donor
I have a tdi75 and had to fully drain the tank after a misfuel incident. I did it through the bottom of the filter and got the tubes totally dry and it did indeed reprime after a few seconds of turning.

Is there maybe an airlock further up the pipes towards the engine? Could you pull the fuel hose off at the engine end and see if there is fuel coming out maybe?


Sent from my iPhone using Tapatalk
 

audifan

A2OC Donor
Tandem pump sucks the fuel up, gravity takes it back. If you can get hold of either a squeeze type pump or a shop vacuum you can disconnect the fuel inlet pipe from the tandem the suck the fuel to that point, clamp off disconnect pump and reconnect to tandem. May still take a bit of cranking to get it to the injectors but better than killing the battery and starter. Try removing the fuel filler cap as that can stop the lines priming quickly.
 

Disco Stu

Member
Have walked away from this today as I’m struggling, may get a couple of hours on it tomorrow but it will probably be Thursday next time I can look.

Took the filter back off twice now to double check that it is in correctly and all looks ok, turned over several times still to no avail

Unscrewed the drain plug on the filter as a last ditch attempt and it’s bone dry so going to have a look and see if I can manually draw fuel through
 
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Alan_uk

A2OC Donor
My garage had that problem last year with my TDi and had to keep it in overnight.

Garage said the battery was weak so couldn't turn the engine over fast enough to suck the air out of the fuel line. They put it on charge overnight and used a boost battery as well. My battery is 2.5 years old 85aH Varta F19.

I suspect that they got air into the system and then flattened the battery trying to start it. Suggestions from this forum included overtightening the fuel filter nut (2Nm tightening torque) and cracked the housing. At the time I got the garage to fit Depronman's improved filter bolt. In a conversation with him he said:

I always hold the accelerator full down whilst cranking the engine. You can save some cranking by taking the fuel pipe off the metal pipes at the front of the engine then attaching some clear pipe about a metre long and sucking on the clear pipe. This will pull fuel from the tank into the filter and through the pipe work. Stop when you see fuel in the clear pipe the quickly remove the clear pipe and reattach to the metal pipe. Fuel should be a lot closer to the lift pump now and therefore the pump as a lot less work to do. Accelerator full down and crank until engine fires up
This as never failed for me
 

Disco Stu

Member
That’s great, I was thinking of something like sucking it through and that’s given me a little food for thought. Now just need to find some adequate enough clear pipe.
 

sco

A2OC Donor
Have walked away from this today as I’m struggling, may get a couple of hours on it tomorrow but it will probably be Thursday next time I can look.

Took the filter back off twice now to double check that it is in correctly and all looks ok, turned over several times still to no avail :)

Unscrewed the drain plug on the filter as a last ditch attempt and it’s bone dry so going to have a look and see if I can manually draw fuel through
Strange that the filter is dry - it's the lowest point in the system so should fill by gravity - have you mis-connected the filter pipes by chance?

Simon.
 

spike

Well-Known Member
Any chance the fuel level is low in the tank
The fuel gauge level sensor unit incorporates a reservoir which is fed via a flap valve from the tank. This reservoir contains the fuel suction and return lines. The valve can clog up causing a severely restricted fuel supply once the tank is below approx quarter full (best guess) Above this level the fuel will spill over and fill the reservoir.
If the tank is fairly full the theory goes horribly wrong
More info on the fuel level sensor unit in a separate thread - https://www.a2oc.net/community/index.php?threads/starting-problem-bhc-diesel.39275/post-349143

Cheers Spike
 
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Disco Stu

Member
Hi,
No not misconnected the fuel lines as it’s the later paper element type, so no fuel lines were touched in the process.
I did think fuelling so I went out and bought a gallon so at least the warning light wasn’t coming on, could possibly do with another gallon or two to make sure it does cover the fuel sensor or take it out and see about cleaning it up (after seeing the other thread)
 

depronman

A2OC Donor
I agree with the above comments regarding the fuel filter being dry, as Simon as already stated the filter is the lowest part of the fuel system and therefore if the line from the tank to the filter is clear and there is fuel in the tank then gravity will get diesel to the the filter
I would suggest that you fully remove the metals drain screw and place a container under the filter, fuel should start to run out of the hole where the screw fits, it it doesn't then the problem is between the filter housing and the tank.
If fuel is flowing, fit the screw back in place and hand tighten only, remove the rubber pipe from where it joins to the metal pipe at the front drivers side of the engine, using a piece of clear tube and suitable connector tube suck until fuel is seen the clear pipe. clamp the rubber pipe and refit to the metal pipe. Cranking will still be needed but much less of it as the tandem pump only need to pull the fuel about a foot as against about 12 feet
 

depronman

A2OC Donor
it does suggest that spikes theory may well be correct. worth taking the sender unit out and cleaning it whilst the tank to near empty

cheers,
 

Vic

Member
Had the same problem. I used another car to pull me with the rope on gear and started that way. I know that this is not the healthiest way to start the car.
 

damadgeruk

Member
Had the same problem. I used another car to pull me with the rope on gear and started that way. I know that this is not the healthiest way to start the car.
I had to do this to start my Focus (having run out on the fuel station forecourt!). I've also returned to my Landy (V8) with a petrol can after running out to discover one of the other cans travelling with me was full!
I try not to run out though don't always dash to the petrol station when the warning sounds, I'll decide. ;)
 

audifan

A2OC Donor
I'll go for no fuel in the tank. If it was left for a couple of days with the drain screw missing / leaking. No mention of fuel coming out when the filter was changes especially when the lines were not clamped. As Pinky will testify leaving the drain plug out is the perfect ( if slow ) way to completely drain the tank.
 

Robin_Cox

Member
Bearing in mind my own issues could there be a combination of system having been drained and the tandem pump getting a bit weak/seals beginning to go so it is not pulling as hard as it might? Is there any sign of leakage around the tandem pump from when there was fuel there?
 
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