Td5 Air issue in the fuel system

Hello guys

Last night my 90 has stopped on the road. I was pushing a bit from the engine and, suddenly, I felt a loss of power and a few seconds before, it turned off. It's very hot around here, in Portugal, this days (don't know if this is relevant).

There's no warning lights. Half tank.
The pump made a lot of noise after trying to get it alive again, but that was clearly because it was pumping air and diesel at the same time. I actuated the self bleeding system several times and I almost put the engine to work twice, but with no success.
I am one of those that can't fulfill the tank, or even have it almost fulfilled, because it throw the diesel out, which I believe it's due a stucked breather.
Also, when I was trying to get it to work, I could hear the diesel moving inside the tank, like if I was blowing through a tube into a big recipient with water. I mean, like big bubbles noise inside the tank.

Had to give up and call the assintance. Tomorow they'll take it to the workshop.

I doubt it's a pump issue itself. In fact, it made this noise for a few days about two months ago, but the 90 always rolled normaly. Than it normalized.

What´s your thoughts?

Thank you!
Dinis

The blocked breather might be the problem

I hope so, but, honestly, I can't explain completely in what way or the cause/ effect of this episode.

If the blocked breather is restricting air from entering the tank, then the air pressure in the tank will slowly reduce until the pump lacks the power to pump out any more fuel. With the engine off I imagine that air will gradually force its way back into the tank, perhaps making the bubbling noises you heard. That may all be nonsense of course, but I would start by fixing the blocked breather.

The other thing that happens with TD5s is that the fuel can leak out from around the place where the pump goes into the tank. When the tank is full this is below the level of the fuel. There' an arrangement with a metal collar like a large jam jar lid which threads onto the hole in the tank and clamps the pump down. There's also a rubber seal. As this is difficult to put together, you find that the jam jar lid has been cross threaded or he seal isn't properly seated, if any previous owner has had this apart.

I had an intermittent cutting out problem which turned out to be a poorly seated fuel filter. The inner rubber washer had somehow got rucked up and it wasn't sealing. If it's a breather problem, will it run with the fuel cap off? Obviously I'm not recommending a long drive with hard left hand cornering like that, but it might help narrow things down a bit. Is there any way of testing the fuel pressure? You should see a healthy 60 psi at the head.

Brown

I don’t believe it’s the sealing ring of the pump, because even with the diesel level on the last mark (not topped) it leaks. In fact the leak comes somewhere from the top of the tank but also from the fuel cap.
The fuel filter is brand new and I’m quite sure it’s properly fitted.
Btw, the fuel cap is a Britpart one and it feels cheap actually, but I don’t believe it’s envolved in this problem.

Hi sounds like your injector seals are on the way out, but maybe the pump is knackered, by the way I would recommend a genuine fuel filter for a td5, having a side by side comparison of a mann one and genuine the genuine looks far better, only needs changing once a year

dinisrosa said:

Brown

I don’t believe it’s the sealing ring of the pump, because even with the diesel level on the last mark (not topped) it leaks. In fact the leak comes somewhere from the top of the tank but also from the fuel cap.
The fuel filter is brand new and I’m quite sure it’s properly fitted.
Btw, the fuel cap is a Britpart one and it feels cheap actually, but I don’t believe it’s envolved in this problem.

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Don't forget that on the defender the fuel pump hole is quite deeply recessed into the top of the tank, so it'll start leaking with the needle just below the 3/4 mark on the gauge. The equivalent Discovery had a much flatter tank so it's less of a problem. Those clip on connectors that join the spouts on the top of the pump to the fuel lines can leak as well. It might be worth cleaning everything up with some sort of solvent (I get myself a few cans of the very cheapest brake cleaner I can find on Ebay for these eventualities) and then it'll become clearer where it is coming from. If you're losing diesel out of the fuel cap, it may just be because it's sloshing around and trying to escape when you go round sharp left hand corners. At least if there's fuel getting out you know that there's air getting in.

I'd say it was worth testing the fuel pressure arriving at the engine before taking the injectors out.

Brown said:

Don't forget that on the defender the fuel pump hole is quite deeply recessed into the top of the tank, so it'll start leaking with the needle just below the 3/4 mark on the gauge. The equivalent Discovery had a much flatter tank so it's less of a problem. Those clip on connectors that join the spouts on the top of the pump to the fuel lines can leak as well. It might be worth cleaning everything up with some sort of solvent (I get myself a few cans of the very cheapest brake cleaner I can find on Ebay for these eventualities) and then it'll become clearer where it is coming from. If you're losing diesel out of the fuel cap, it may just be because it's sloshing around and trying to escape when you go round sharp left hand corners. At least if there's fuel getting out you know that there's air getting in.

I'd say it was worth testing the fuel pressure arriving at the engine before taking the injectors out.

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Thank you brown for the valuable information. I didn't know about such recession on the pump hole! It can explain the leak, as the fuel cap is a cheap one and it doesn't seal well at all, which may clear the eventual breather fault..

Discodevon suggestion about the injectors seals also makes sence, but I'll work on the easier causes for now.

Thank you, guys

As suggested above

Remove the fuel filler cap and run a purge cycle. See if the engine now starts, if so then the blocked breather is your fault.

I had those exact symptoms for ages! I replaced fuel lines, pump, injector seals…. It turned out to be a blocked fuel filter! Cheap and easy place to start.

Mudstyler said:

I had those exact symptoms for ages! I replaced fuel lines, pump, injector seals…. It turned out to be a blocked fuel filter! Cheap and easy place to start.

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Yes, we had something similar with a friend's TD5 a while ago, which was cutting out and running poorly. It was a Britpart filter, of course. As it had been changed recently, we didn't think of this as the culprit. And anyway, surely even Britpart can't mess up something so simple as stuffing a can with fluff? However, on taking a close look inside, the filter medium was all wadded up against the top and must have been restricting the flow. A new filter (a Coopers, I think) and it was much better.

Hello guys

Just to let you know that the problem was indeed the fuel pump. The breather was blocked too (easily solved with a shot of air pressure), but it wasn't the bad guy here about the leaking. When I took the pump out, it hadn't the seal instaled!.. So, it would always leak anyway.

The pump was very, very dirty! Gave it a very good clean but I prefered to use the new one I bought some time ago (didn't want to risk to do the job twice, since it's a bit of a pain taking out the fuel pump from a Defender). It's a Meat&Doria one. Diferent noise (a bit louder and somehow rough noise) but everything else seems to work as the original one.
Did the auto purge twice and after a bit of insistence, the td5 fired up again.

About the original VDO I took out, is there any way to test it out of the car? What's the pressure it must provide?

Thank you!
Dinis

Btw, I'll do the injector seals too, since it they have 390.000km already.
Do you recomend looking on anything else when I do this job?

Glad you are sorted, I really recommend genuine fuel filter for the td5, and change it once a year without fail