Bad Fuel In Mk3 Mondeo 2.0 Tddi

[jeebowhite]

You should be able to swap any other relay with that one

[Cobraone3]

Update to this on going saga.
Found out what was in the tank, it was about a litre of heavy hydraulic oil, in 25 litres of diesel. So at least the main pump and injectors have not been washed dry with water. Relays are fine, fuses fine.
Now back to the main issue, lots of investigative research and I have found out that there is a micro filter in the tank on the sender unit (fuel guage, fuel uplift and return) and access is under the rear seat. I also found out that the lift pump does not operate ALL the time, only when needed, probably pressure orientated. It works for seconds when the ignition is turned on, unless there is a major problem. So by the time I had got down there with the meter probes, it had turned off, so zero reading.
Now I do not have the space to drop the tank and the access to the sender is offset from the hole under a section of steel, Probably buy about 1/2 an inch. It is my intention to cut this back (trim you might say) so that I'll be able to withdraw the sender. If as is suspected the filter has slime or a blockage, I'll have the answer.
So unless anyone has an opinion as to why I should not do this, I'm on it tomorrow am. I will keep you all informed, It may help somebody in the future.
Colm.

[jeebowhite]

What the heck is hydraulic oil doing in there lol

[Cobraone3]

It was in the bottom of a transfer container, sometimes get fuel that way and the canisters are clear/opaque, you can see the colour etc. But this one was green solid and had not been through the normal cycle of cleaning.

[jeebowhite]

Oh dear, not very good!

[Cobraone3]

No, but on the up side, Now we know what we're dealing with. It also gives more creedence to the micro filter on the sender option, in that the oil being thicker than diesel could have clogged that filter. So the first stage of that starts shortly, opening the metal to allow full access under the seat and draw it out.

[jeebowhite]

Good luck, maybe do a step by step as I am sure someone somewhere will need to do it

[Cobraone3]

Right, Firstly thanks for the help and suggestions through these endeavours. Now not there yet,95%. The car runs on first start up, remember in the early days, if I filled the filter the engine would run for 10 - 12 miles unhindered then stop.

Now recap on what I have done (i will put a proper posting up when complete). Fuel tank accessed from in the car and sender removed, cleaned, checked. Tank emptied and wiped out, got rid of a load of slime, gunk and rubbish. Pipes blown backwards from the filter to the tank, both feed and return pipes.

Sender replaced into the tank, Refuelled, fresh diesel, new filter, all reconnected, (oh, fuel filter filled with diesel). Started after 3 10 second bursts, only had to crack two injectors. I did loosen all injectors in order 1-3-4-2, twice to ensure no air left. Ran smoothly.

Some idling and spirited driving for an hour and a half, with a very occasional hunt/kick. Stopped engine. Tried to restart later, refused to stay running for more than 2 mins and while it was running, the lift pump sounded like a jet engine starting the noise level rose and then the engine started to hunt then stopped.

Since that time I've tried little things, nothing major, mostly checking my work again & again.

Now, she starts when stone cold and runs for however long I want her to and do not hear the lift pump. Once stopped however, on restart which could be 2-3 hours later, off goes the lift pump and the engine cuts out. Incidentally, in this mode I can travel half a mile with four restarts. There are NO warning lights on the dash (they do work) when this happens.

One diesel engineer (they are all booked for months ahead) suggested that it is the lift pump that is at fault, as it is not a Bosch. But why does it work when the engine is cold and the engine used to run if the filter was full.

Stumped again.

[Cobraone3]

Hello, back again with the on going saga and some updates.

Been stuck for a while, not able to get to the car, as the missus bought a puppy and guess who's had to look after it before it was allowed outside. Exam time for the kids.

So checks have been done and the leak off test was perfect, nothing wrong with the injectors. What was strange though, was that even though the engine would not stay running ( started, ran for 30 secs, started hunting/running rough, white smoke from the exhaust, stop.) we could not get it to operating temperature. Set up the leak-off pipes (Note: not common rail so each of the injectors has TWO fuel return nipples, as they link/feed to each other). The engine not only started first time, but ran for half an hour not missing a beat. In that time the leak off was +- 5 mil, a touch less on 2. So engine all good.

Reconnected everything but kept the clear pipes in between the injectors down to the main return and restarted. The engine ran as before 30 secs, white smoke, stop. As the clear pipes were still on, we noticed that the bits of fuel in those pipes was being sucked BACK into the injectors instead of flowing out.

Checked the feed pipe was clear back to the filter, checked the return pipes to the filter and down to the metal pipe connection by the bulkhead. Then we put a pipe on that return pipe and with a bicycle pump pushed the air down the pipe. Fuel then came out of the filter where the T section for the return normally is. So instead of bubbles in the tank ( filler cap off) as returning fuel, it was pushing fuel back through the feed line. There is a brand new lift pump in between. This is where the crux of the problem seems to lie.

So once again boys and girls, any ideas?

Thank you in advance just for even thinking about this.

[jeebowhite]

I must admit you have exhausted any idea I would have come up with... So you replace the fuel lines with leak off pipes and it works, but when you reconnect the standard lines it stops again? Sounds like there is a blockage further in the lines?

[BOF]

I'm out of my depth, here, not knowing much about the specifics of TDDIs, but

• the test where you couldn't get fuel gushing out still sticks in my mind; the rest of the symptoms sound at least a bit like 'getting some fuel, but not enough' so that test sticks out to me; I am not clear, with the other stuff that you have done whether you have cured that, or not
• Is it any better if you leave the ignition on for a while (so the 'whooshing pump' has some time to whoosh) before trying to start it, or does that make it worse? does the whooshing stop after a minute or two?
• I seem to recall some thread where someone had, eg, the silvery cap/seal off a RedEx container in the tank, with all sorts of odd results; could there be a physical object that sometimes blocks off the flow and sometimes doesn't?
• Is it at all possible that one of the pumps is 'wired' backwards (by wired I mean either electrically or the pipe connections)? Seems implausible but that would be quite a strange one.
• Alternatively, could the connections to the injectors have been reversed?

After that I think I'm all out of ideas, even strange ones.

[Cobraone3]

No just the return pipes in between the injectors, as on this engine the leak off nipples are banjo tee pieces. set for the test it was as if the thing could breathe so to speak. When connected back up for normal running, that's when we discovered the back pressure 'cos we could see the flow was not going to return, but back towards the injector - over fuelling. The main fuel line - feed - has not been touched as the engine runs and is therefore being fed. The flexible return lines have been blown through, those in the engine bay area. The metal one that goes from the front to rear was blown through with a bicycle pump attached via a tube. That's when we noticed the fuel being pushed back along the 'feed' line.

[Cobraone3]

Thanks BOF, No whoosing sounds. But the connections I think are on right, it was dark and cold,very cold when that was done. I'll be checking tomorrow.

[Cobraone3]

Thanks BOF & Jeebowhite,

Recapping, Plenty of fuel from feed, engine ran really well during leak off test, for over half an hour, responsive to throttle. It's the return that seems to be the issue. And why when blowing back to the tank via the return pipe, is fuel pushed up the feed pipe, into the filter?

[jeebowhite]

I must admit mate I know little else, but I believe the return is dropped back to the filter.