Hi guys,

I'll try and keep from waffling too much but I want to be as detailed as I can on this main post.
For some background, my car (2005 Mondeo 2.0 TDCI) had been on limp mode since I bought it in early December. This turned out to be because someone had removed the injectors (likely for cleaning) and reinserted them in the wrong order and all I had to do was recode the injectors in the new order, good as new.
ote, I didn't get round to performing a leak off test and it seemed my injectors were all happy once they were coded in the right order.

Before and since then, I've been flushing the fuel system with Red X fuel system cleaner with night and day results (strongly recommended).
On the day it spluttered to a halt on the motorway (misfire + smoke then complete shut-off. no restart), and for 2 days prior, the car was unhappy at idle (RPM would vary by about 10 0rpm or so constantly, something I put down to the loose alternator belt causing a variation in engine load) and it became much easier to stall.
As far as I could tell from city driving, there wasn't any power loss or hesitation at any speed above 1.3k ish rpm.

On about my 3rd overtake on the motorway (55ish to 70) at full throttle and max boost the miss firing and subsequent cut off occurred.
Bear in mind this was the third time (all 3 in the same 10 min window) that this car has been at max power and max throttle since at least early December 2021 when I bought it.

After getting a tow home, I plugged my tunnel rat into my laptop and got codes P2291 and P0251, both on my Powertrain Control Module reporting low fuel pressure (see photos attached).
After recharging my battery (ran out trying to crank and stay warm on the motorway), I went back out today and managed to hit the 250 rpm crank speed needed to start but my Fuel Rail Pressure was a measly 435 PSI peak (30 bar) and just 87 PSI (6 bar) when the ignition is on. Again, see the pics attached of my OBD ll scanner

Returning to my point of failure and the months leading up to this, this car had been in limp mode for god knows how long and probably never had any sort of injector cleaner or fuel system cleaner in it at all and god only knows when the fuel filter was last changed.
This leads me to believe that giving her the beans with the Red X flushing the system meant that I dislodged some goop in the system that has subsequently blocked up my fuel filter of unknown age. Something Forscan lists as a potential cause.

Alternatively, given the recent poor idle I mentioned previously, my high-pressure pump might have given up the ghost when it was at max pressure. Hopefully not but we can't rule it out...

I'm more than happy to hear other people's suggestions as to the root cause and I appreciate your ideas.

 

When you say flushing the fuel system... have you been using the Redex neat? only, the diesel has a lubricating quality to it, important to keep the the hp fuel.pump lubed.... if you've been using Redex neat, that means the pump has been running without lubricant!.... just a thought... 🤔 

Did you know you'll have longer cranking life if you pull fuse F8, it feeds the glowplugs and takes a heck of a lot of power from the battery for... wait for it... 30 seconds every time you turn on the ignition. Car will start in the cold without glowplugs, and you'll find engine will crank a little faster too. 

 

I added the RedX to a full tank so its properly diluted. I added more than 1 'shot' but not before reading that it wont do any harm in 53 liters of diesel.

That is a very good point, I didnt think of disabling the glowplugs, I'll do that when I do my leakoff test and pressure tests!

So have you changed the fuel filter? 

Edit: I think I have the wrong car. I could be talking mk4/2007 (sorry, I don't know mondeo models by year. It seems the mondeo was a late adopter)

 

 

This the euro4 ? I'm looking at such a system at the moment, though I'm no expert. The in tank fuel pump runs at high load, filling the little pot the hpfp lifts from. I have found when priming my car without the ignition on, I can empty that pot and get air. I think it's related to how quick the pot fills through the mesh bottom. I have seen this twice while trying to prime mine, though I must stress, I can't make mine work either.

I'm looking at your fault as possible air ingress. Another route for this is the seals where the lines connect, and the fuel filter housing. There may even be a diesel heater circuit, in and out of the filter housing. As the hpfp got to high demand, maybe you pulled air.

Air ingress often leads to low pressure codes. You can generally see the air in the pipes though. If I have your engine right, it's the vdo pump on the end of the cam, and the feed goes in the top. A clear pipe, from the filter. The filter being high on the front of the lump, over the alternator, opened with a large socket.

 

Air is a nightmare sometimes.

1 hour ago, iantt said:

So have you changed the fuel filter? 

Its currently en route, as well as my injector test kit. Hope it arrives soon so i can rule it out asap

23 minutes ago, Thomas.C said:

Its currently en route, as well as my injector test kit. Hope it arrives soon so i can rule it out asap

When you remove the filter , check for any metal filings. That's a sure sign pump has ***** itself. 

1 hour ago, KugaDave said:

I have found when priming my car without the ignition on, I can empty that pot and get air.

Hmmm, my priming pressure is a constant 8 bar, suggesting theres no leak or air ingress at that point. When i crank I get 30 bar (out of like 800 its suppoed to be) and it very quickly returns to my 8 bar. What are your thoughts?

11 minutes ago, iantt said:

When you remove the filter , check for any metal filings. That's a sure sign pump has ***** itself. 

I prey it's just full of 16 years worth of gunk but I'll give it a close inspection. Is there a good way of opening it without buying a special filter opening tool? A hacksaw would work i guess

I think you prise the overlapped bit straight with pliers. There's pic some where on how it's done best not use hacksaw as that creates  filings. On the X-Type forum (it uses same parts as mk3 Mondeo-) there's some pics of what to look for in the fuel as you wont see filings as such, but a metallic sheen.... and best viewed in a black aerosol pot. I'll try n find the link.... 

https://www.jaguarforum.com/threads/x-type-diesel-venture-into-the-unknown.117344/page-6

look at the pic on post #53

1 hour ago, Thomas.C said:

Hmmm, my priming pressure is a constant 8 bar, suggesting theres no leak or air ingress at that point. When i crank I get 30 bar (out of like 800 its suppoed to be) and it very quickly returns to my 8 bar. What are your thoughts?

You have a different fuel system to me then. I don't have a pump in my tank that sends fuel out at pressure. I have a pump on the engine that sucks/lifts. Putting low pressure in the supply pipes that draws in air. It's not applicable. Sorry pal. I can't help

18 hours ago, KugaDave said:

You have a different fuel system to me then. I don't have a pump in my tank that sends fuel out at pressure. I have a pump on the engine that sucks/lifts. Putting low pressure in the supply pipes that draws in air. It's not applicable. Sorry pal. I can't help

Apreciate the input, do you know of any good ways of detecting/ finding the source of a air leak? 

On 2/8/2022 at 1:37 PM, Thomas.C said:

Apreciate the input, do you know of any good ways of detecting/ finding the source of a air leak? 

Sorry pal, I have never seen your fuel system. Only my later one.

I will offer an alternative explanation of what happened though. The past owner had problems. It's not your cleaning that started this. He had the injectors out for a reason, and sold you the car in a broken state. This wasn't underhanded as it was in limp mode, with a fueling problem. You swapped the injectors about and it seemed fine. 

 

Later you have been loosing fuel pressure. It seems the in tank pump can get your rail up to 6bar by pushing on the hp pump at 8bar. Does some go back to the tank? Most systems have a return, that to me, appears to be after a high pressure regulator. I'm actually stuck figuring out it's action on mine, regarding it's state with the ignition on/off/running. Different system though.

 

One common cause of fuel starvation is simply blocked filter. I'm not sure if you can put a gauge in your line feeding the hpfp to see if that 8 bar vanishes once you make a demand on flow. Which would indicate a flow restriction. Though, putting in gauges seems daft, when the filters condition is so import in this diagnostic process. It's a service item, so does need changing. It also fetches stuff from the tank constantly. If your hpfp has been grinding away, the debris will likely be found in your filter cup. In mine, it looking like brass filings. So I knew my pump had failed.

 

In a line, we have your tank pump that works. Then the filter, a service item you must check before going any further.

I guess there is another option... pull the fuel feed off the hpfp and put ignition on. Fuel will go everywhere with an 8 bar capable pump pushing it. That would show fuel flow capability through the filter, but not what it has been catching. It's just a partial diagnostic.

You need to open that filter up. Until then, we are ***** in the wind.

There's no lift pump electric or otherwise in the tank on the mk3 tdci, only on the much older  TDDI version 

8 hours ago, nicam49 said:

There's no lift pump electric or otherwise in the tank on the mk3 tdci, only on the much older  TDDI version 

I should of been suspect at the mention of 8 Bar. However, there are plenty of in tank sender units listed for the <07 2.0 tdci mondeo. Rated 3.8 Bar.

Not that I don't believe you. I can't make sense of a lot of it. Either way, the filter needs looking at still. If the hpfp does the lifting then air ingress at any of the connections it pulls though is possible. Even the filter.

 

As I say, hands up, it's not a system I know. I'm just offering some generic advice. Those push on fuel connections used by a few car groups are a common failure point it the pipework is being drawn through

On 2/7/2022 at 5:22 PM, iantt said:

When you remove the filter , check for any metal filings. That's a sure sign pump has ***** itself. 

Changed the filter today. I made sure to prime it first by filling it with diesel and sucked all the air from the outlet port until fuel came out when it was installed aaand 0 change.

Literally the exact same priming and crank pressures on the rail. Sigh.

I did the non-start test (unplug brown pump plug and all injectors) and still identical pressures (6 bar on ignition, 30 on crank).

I was going to perform a leak-off test too, but my dad (who came down to lend a hand) reasoned that if there's no pressure difference with all the injector's electrics unplugged, it would mean that there's no point. I'm not sure I agree, but it was getting late...

It looks to me like the high-pressure pump has gone. I haven't cut open the old filter yet to check for forbidden glitter, but I don't see what else could have gone bang? 

If there is no pump sending fuel out from the tank, where does the 6 bar come from.

 

The puzzle pieces don't fit together in my mind. 6 bar is within reason for a tank mounted pump. Do you have clear pipe between the filter and hpfp to see if fuel flows for a moment as you switch on the ignition? Perhaps you could pull the fuel hose off the filter and try to fill a bucket. I really want to know where this 6 bar is coming from. Forums are full of people saying everything, so you really need to see for yourself what's true. If like mine, and as suggested, the hpfp does all the lifting, then the 6 bar is presumably a lie. I would have to crack open a high pressure line (often people do so at an injector feed) to see this 6 bar was a lie, then it would look like the sensor that's perhaps, system depending (I have no idea what you have) on the common rail. Some fords have the sensor come as part of the common rail, though it is a separate part, they want £400 to sell you more than you need. So It's scrap yard time for them. 

 

Just to be sure... this 6 bar was measured after priming but before the first cranking over? If it's since, then it could be trapped in there I guess. Though I don't think it can be, as priming would be difficult with the valves sat that way at rest. I'm just speculating though 

 

Again, I'm severely handicapped not knowing what you have, but the fuel usually enters the filter from the tank, into the filter body. Then passes from outside the filter element to inside, and out. The shape of the housing my show how the clean stuff leaves the middle. This means the crud is in the filter body, the pot, not the filter element. With most filter designs. 

On 2/10/2022 at 7:36 AM, KugaDave said:

I should of been suspect at the mention of 8 Bar. However, there are plenty of in tank sender units listed for the <07 2.0 tdci mondeo. Rated 3.8 Bar.

Not that I don't believe you. I can't make sense of a lot of it. Either way, the filter needs looking at still. If the hpfp does the lifting then air ingress at any of the connections it pulls though is possible. Even the filter.

 

As I say, hands up, it's not a system I know. I'm just offering some generic advice. Those push on fuel connections used by a few car groups are a common failure point it the pipework is being drawn through

I just hooked up my leak-off test and cranked the engine (I don't know if you are supposed to remove any electrical connectors for a non-starting test so I only removed the leak-off pipes).
After 10 seconds of cranking on a failing battery, I managed to get about 10ml from cylinder 1 and lesser, but still quantifiable, amounts from my other three.

The fact it came p*ssing out at a slow, 10-second crank shows that it is well and truly buggered.

I'm going to charge up my battery tonight and run another test at the full 250 rpm cranking speed.

 

Also, I've cut open my old fuel filter of unknown age and I can't see any forbidden glitter in the housing or paper so far but I'll have a closer look with a magnet tonight.

In place of shavings, there was no small amount of brown sludge at the bottom of the housing and soaking the filter. gross.

 

I'll post an update tomorrow.

I think she's had it. Runs like a dog and has crazy crank case pressure