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Discussion Starter · #1 ·
Hello I am new to this forum so appologies if this post is in the wrong place. My E34 525tds had developed a problem with fuel supply after being sat for a few months.
If the car has been switched off for any length of time (half an hour or more) you have to crank it for upwards of 30 seconds or a minute before it will fire, even when the engine is still warm. If I open the bonnet I can see that there are air bubbles in the fuel line when cranking, but when I start the car these go away. Once the engine is started it runs absolutely perfectly and I have no problems with it cutting out or anything like that. It's also worse it it's parked uphill
It seems to me almost like there is a non return valve stuck open somewhere or something like that. I found a forum post from a few years ago of someone having exactly the same trouble, so I shall attach a screenshot of that post.
I have bought the car when I was 14 (4 years ago) for £250 and it has always been absolutely reliable and I would like to get it back to such a state as I'm planning to get it insured in my name for the first time and actually be able to drive it myself (rather than having my father drive me around in it).
Any help would be enormously appreciated.
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I had this exact issue on two bmw with the tds engine. Mine would start great from cold and then turn over for approx thirty seconds when it was warm and been stood for a while. In the end I fitted a relay which activates the cold start procedures and then switches off after about twenty seconds. What this does is it activates the priming pump as it would when it’s cold. Sorted the problem out. I think the kit is still sold on eBay as it was done for the tds engine which was used in the Range Rover.
cheers
Jim
 

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This is the link to the kit on eBay. Dead easy to fit and sorted mine out a treat
cheers
jim
 

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Discussion Starter · #6 ·
I had this exact issue on two bmw with the tds engine. Mine would start great from cold and then turn over for approx thirty seconds when it was warm and been stood for a while. In the end I fitted a relay which activates the cold start procedures and then switches off after about twenty seconds. What this does is it activates the priming pump as it would when it’s cold. Sorted the problem out. I think the kit is still sold on eBay as it was done for the tds engine which was used in the Range Rover.
cheers
Jim
That does sound like it could be the culprit, however in my case the issue persists regardless of whether the car is warm, hot, or stone cold. The only exception is if the engine has been running in the last few minutes.
 

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Discussion Starter · #7 ·
This is the link to the kit on eBay. Dead easy to fit and sorted mine out a treat
cheers
jim
Thanks very much indeed for the link
 

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Discussion Starter · #8 ·
In addition to all of this, the problem developed extremely suddenly. Before the car was parked up, and even when I started it a couple of times whilst it was parked just to warm it up, it never ever had a problem starting. The problem only started when I finally got the car 'out' again a few days ago and every time I've gone to start it since I've had this issue. Initially I thought it might be a stuck on return valve, but I don't think there is such a thing in the fuel system of one of these is there?
 

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Discussion Starter · #9 ·
if you leave it sat for any length of time and then go to crank it you can see more air than fuel in the fuel line going to the injector pump. Then you crank it and it turns into the occasional bubble, then again and you get a constant stream of fuel, then again and again and eventually it'll start, but this process can take some time and appears to be significantly worse when parked on a hill facing upwards.
 

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Discussion Starter · #11 ·
Yesterday I put a couple of gallons of diesel in so it is now about 1/3 of a tank, tapped the filter housing and twisted the filter slightly just to see if it freed something up. I don't know whether it was coincidence from any of the above but over the past day the issue seems to have disappeared. I also changed the fuel filter today. There are 2 possibilities from here:
1.) It is the fuel pipe on the pump in the tank which has been mentioned on other threads and putting diesel in cured this temporarily as it raised the level above the pipe.
2.) Something I did with the fuel filter or housing freed something up or cleared something out and it cleared any remainder of air out of the system itself (changing the filter might have done this anyway, but my filter hadn't arrived yet).
The only way I will know for sure whether it is one or the other is to run it well below a quarter of a tank and see if the issue comes back. If it does then number one is true, and if not then number two is. I'll give an update when I know what's what.
 

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Discussion Starter · #13 ·
I've filled it up with diesel and have done about 100 miles since changing the filter. So far no starting problems so I'll update once it's gone well below 1/4 of a tank
 

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Discussion Starter · #14 ·
I believe I have found the culprit! The hose in The pictures is the return hose for injection number one, and I had to bodge it together quickly for the MOT as it was leaking and the MOT centre had closed. The leak went away for a day or two and then started again, and when it started leaking again my starting problem returned. I then replaced the hose with a proper piece of fuel hose (not the one in the photo) and hay presto, my starting problem went away!
 

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