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Discussion Starter · #1 ·
04 Zetec tdi

I've looked through the old messages and found some broadly similar to this but they don't answer the specific point I want.

On three (so far !) separate occasions over the last month or so I've had the situation where the engine fires, runs for a few seconds then stops; on investigation, there's a visible air bubble in the fuel line from filter to pump.

The first time it happened, I'd just changed the oil so nose was way up in air (car on ramps) and oil level was (deliberately) a pint or so below capacity (I've always done that & had a final top-up when car level again). When engine stopped I blamed that on engine management system detecting a low oil level & shutting system down as a safety precaution.

An unrelated electricalfault caused the warning light to come on and I dropped the car in to a local auto-electrician. They found the fault (a loose air pipe that I guess I'd knocked off whilst changing oil filter) and fixed it but when they went to drive the car out of the workshop they got the air in fuel line problem. I'd already told them of the previous fault (in case it was relevant to warning light) so they were able to bleed system & restart. We discussed fault & agreed to replace fuel filter In fact, I'd read through this forum to arrive at that possible cause and they'd independently arrived at a similar conclusion so we were both convinced it was the right thing to do and it was indeed pretty grotty so we both thought that would be the end of the matter.

Car ran OK for a few days then I parked it up & didn't use it for 3 days. Engine fired, ran 10secs then died. Air in fuel line again ! I'm getting quite good at bleeding the system so had it running again inside 5 mins & it's been OK for a few more days. However, I've done nothing that will guarantee it won't happen again.

The auto-electrician recommended a local fuel injection workshop but the guy there really wasn't very helpful. Gist of his 'advice' was that the fuel pipe system was a nightmare, shouldn't really work at all but it seemed to most of the time and that he wouldn't have anything to do with Fords & always sent prospective customers to a main dealer with warning that they'd get a huge bill. Rather than paying Fords a fortune, I'm fairly happy to carry a spanner & bleed system when needed though I would of course prefer to have it working correctly if that can be done economically. In particular, I don't want to fit a new pump as I'm convinced that there can't be much wrong with a pump that works most of the time.

I can't really see what else is likely to be causing this problem other than inleaking air somewhere - but it doesn't inleak most of the time so finding it will be next to impossible !

I wondered if it might be worth fitting an auxiliary elctric lift pump so that (i) injector pump would be under pressure when starting & (ii) if it did need bleeding again it would be a real doddle with the lift pump ticking away. Can anyone see any snag with that plan ? Or even, has anyone else tried it already ? And of course can anyone suggest how I might find an intermittent air inleak ?

TIA
 

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Hi,
Try changing the leak-off rail from the Injectors, I have known these to be faulty due to the small "O" rings being at fault.
They can be Liquid tight but not Air tight, and because of this they will have air ingress but not leak fuel out.
Or, try another Diesel fuel specialist, the one you tried seems a work shy get!.
 

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Based on the very short time span between start, run and obvious air in fuel line it ought to be very close to the pump that the air is getting in. I'm wondeing if there is something somewhere near the filter body itself either a seal or at worst a hairline crack in the top of the filter bodyso that there is no obvious fuel leak.
I realise it is more for large regular air leaks but the TIS suggests putting a little clean engine oil on each joint in turn to see which stops the air getting in
 

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Discussion Starter · #5 ·
Thanks Richard - I think you're in the right area.

I bought an SU electric petrol pump from a scrapyard today and tried fitting it.

It wasn't altogether successful but it did throw up some valuable info.

I realise that the petrol pump from (probably) an 850 mini wouldn't have enough capacity to supply all the DERV required for a 2 litre engine but was hoping that it would be sufficient to pressurise the system before starting and when the 'real' pump started sucking the SU wouldn't offer too much resistance. That was the theory but it didn't work too well in practice <g>. Possibly my choice of bunging a bit of almost-correct size copper pipe into the filter inlet wasn't a good enough seal though I thought at the time it would be OK

Whatever the cause(s), the car started well - indeed, bleeding the system with the SU ticking away really was the doddle I expected. However, I could see that the filter outlet pipe was gassing up at a much faster rate than ever I'd experienced before & consequently engine would die, For my first attempt, I'd done the SU outlet to filter inlet in black semi-rigid plastic but I changed that (before pic was taken) for clear plastic. That enabled me to confirm that fuel line before filter had very few bubbles but outlet pipe had lots. Trickling oil around inlet & outlet joints made absolutely no difference. Even coating (the outer part of) the filter inlet & outlet pipes with a jointing compound made little difference.

Restored system to normal & re-bled (a bit harder without SU but still relatively simple) then restarted. Some air bubbles apparent in filter outlet.

Wanting to do something, I wrapped the straight pipe bit of both inlet & outlet connections to filter with PTFE tape. Re-bled . . . . . Engine seemed to start OK & bubble situation seemed better but I'd had enough for one day & packed up.

Still not sure whether its been one of those two joints (or if PTFE will cure !) or if indeed there's some sort of leak in filter body.

I still think the lift pump idea ought to work but it obviously needs a proper capacity pump and maybe some better plumbing.



http://www.flickr.com/photos/[email protected]/sets/72157622631129601/
 

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If you do go down the electric lift pump route. I would suggest the the SU or equivalent should be at the tank end of the fuel line and that you ought to also have a pressure bleed of circuit just before the filter because as you say the capacity of the SU is more than that required which may have been the reason for the increased air
 

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Discussion Starter · #7 ·
I tried to say that the capacity of the SU is LESS than that required - hence when 'real' pump is sucking, it takes everything that SU offers & still tries to suck in air from wherever my mystery inleak is.My expectation was that SU would offer little or no resistance to such suction so perhaps it's just that one of my joints wasn't very good either (I'm particularly suspicious of the piece of copper pipe thet seemed to be correct diameter to fit into filter inlet) and gave an extra chance for air to inleak.

SU shouldn't need any sort of pressure bleed anyway - it's been my understanding that it incorporates some sort of pressure limiter anyway. [the old test for a fuel leak in carburettor etc was that SU would tick away forever when ignition was switched on bit engine not running].

Off to scrapyard shortly to see if I can find a bigger electric pump (they're like rocking horse sh*t these days !) and a joint exactly the same size as the fuel filter inlet. The scrapyard I'm using is one of the few left these days that still lets you wander around the wrecks & find your own bits; most others round here will sell you what's on the shelf but nothing else.
 

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though not from a scrapyard you might find electric pumps on race / rally spares web sites
 

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Discussion Starter · #9 ·
It's a bit soon to say that I've cured the fault (the car has run very well for several weeks at a time andI've only managed afive minute test run so far !) but I am quite hopeful.

For a number of reasons I decided the inleak lay in the fuel filter area. In particular I'm very suspicious of the 'quick release' inlet & outlet joints. An external lift pump is still a good idea but the 'best' answer must surely be to eliminate the need for one - it's run OK without one for five years so shouldn't need one now.

I visited the scrap yard again yesterday loking for a pair of similar joints so that I could replace them (though of course the dodgy bit of the inlet joint is integral with the filter body so only way of curing that would be to replace a possible internal O ring or epoxy that joint up & have an external one a short distance away). Zilch ! No C-Maxes at all (well they never die do they <g>) and no vehicles with the same size joints. Plenty of smaller joints but everything else that size uses good old rubber pipe & jubilee clip or perhaps a 'banjo' joint.

Almost giving up when I opened the bonnet of a Mitsubishi 'Surf' (at least that's what I thought it said but that model wasn't listed when I looked it up in a parts catalogue later) - a biggish 4x4 with a diesel engine - and spotted a bulkhead mounted filter complete witha built-in priming pump. Quick rethink & grabbed spanners !

It's quite a bit bigger than the plastic pot that Fords deem suitable but I thought it should just fit. That & a handful of assorted rubber pipes only cost £10. Didn't seem a lot of point re-using an old filter element so went looking for a new one. Not a lot of parts sellers open on a Sunday afternoon of course so Halfords got my business (& £17 !)

Hardest part of the fitting job was getting rid of the Ford unit without damaging it (just in case I'm ever tempted to refit). Undoing all the bolts still left it lifting up an inch then stopping; looking & feeling for a missed bolt revealed no more so eventually resorted to levering it up with a claw hammer when luckily it saw the error of its ways. The housing it's in seems to double as the alternator bracket so I couldn't make a lot more room. Settled for fitting a new 'rail' between the little ball that locates the sound- deadening unit & a point just behind the o/s headlamp. Since one of them is on engine & other isn't, I fitted a rubber bush between rail & body - that should allow it to act like an extra engine stabiliser bar (not that I felt any need for one otherwise). Fuel filter body hangs off that bracket & bottom doesn't quite foul the oil filter. Plumbing fairly straightdorward: I clamped a piece of rubber tube to the 'spigot' of the old inlet joint but had to cut the outlet joint off (there's slack in pipe if I have to refit it) and attached pipe to another rubber tube; both tubes then clamp to new filter pipes. I ignored the electrical connection which I guess tells you that the filter housing is full of water (both filters have one so I could perhapstry connecting it up if I get the urge but can't really see that it's a very useful feature).

Primed fuel system & bled it again (much easier to do when you've got a priming pump built in !) & started it up. At 1am I really didn't feel like going for a test run so switched off & went to bed. This morning I inspected pipework for any new air bubbles (none found) then started it up & went for a two mile test drive. Came home & checked for bubbles again (still none).


There are several pictures of the project at:-

http://www.flickr.com/photos/[email protected]/sets/72157622631129601

I'll try & post another note in a few weeks time confirming that it's still working OK (or not as the case may be !).

Have to say that the single pump and the plastic fuel filter body with its 'quickfit' joints are faults justwaiting to happen! My Landrover (IIA)used to have a very similar filter to the Mitsubishi's and a (mechanical) lift pump before the injector pump and I never ever had any inleaking air problems.

I'm certainly not defending the alleged fuel systems expert I consulted but can see his point of view. Ford's recommendation is probably to change all the pipes (the rubber won't be a problem but I bet they don't sell the joints alone !) & completefilter unit (again, for the sake of one O ring !) at incredible cost. Wouldn't it have been better to use relaiable components in the first place ?
[when I told my autoelectrician of the fuel man's 'advice' his reaction was "I wish we were so busy we could afford to turn away business"]
 

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Discussion Starter · #10 ·
Postscript

It (sort of) happened again !

This time I was able to work out that one of the pipe junctions I'd made last year had distorted slightly & when engine was working hard it would suck air in through that joint.


Following links are to my Flickr website where you'll see some close-up pictures of the damage & cure :-

<?: prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" />

<a href="http://farm5.static.flickr.com/4040/4696367802_2811316d18_o.jpg" target="_blank" rel="nofollow">http://farm5.static.flickr.com/4040/4696367802_2811316d18_o.jpg
shows</A> how the pipe looked a year ago. Red arrow points to lower joint where nylon pipe was inserted into a rubber one.

http://farm5.static.flickr.com/4052/4695734857_e45336513f_o.jpg
shows the warped end of the nylon pipe. The ‘groove' was allowing air to be sucked in past the jubilee clip.
The cure was to cut of the warped end & insert nylon pipe into a fresh bit of rubber (allowing a much longer overlap than before). Rubber tube connected to filter body & jubilee clips at each end of section.
http://farm5.static.flickr.com/4063/4696370978_4eb3bf6830_o.jpg
The new pipe in position. End of nylon pipe is near my finger tip. Connection to filter body is at top left corner.

Road tested since the repair & it's now flying up hills again.
 

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Hi,I have read your post with interest, and amazed your filter is the same as mine and the only other one I have come across on the internet! Most are the throw away cannister type.You must be quite an expert by now!

I have had my car for 4 years. Do my own servicing and have fitted 4 fuel filters. The first one I couldnt get it to bleed. I thought it would bleed it self like most do. However I had to ask Ford and they said only they can do this with a special primer suction tool. After a long time, and many flat batteries i removed the hard clear pipe from filter to pump, replaced with gates fuel hose with a Peugoet rubber primer bulbin it. This cured the problemfor £6. Filter change is a doodle now.

I have a similar? problem, Intermitant fault- pull up at a road junction and the car just ticks over, won't rev until IT decides, most embarrassing. No fault code showing. After been told by all garages that need to plug into computer for £50 start and no guarentee that that will show the problem. A local fix it lad said if no ECU light on the computer will NOT show anything. He suggested the accelerator pedal is dodgy. No cable, just wires, fly by wire type. I fitted a new one £90. Still no better.

I am begging to think there is an air lock somewhere. The car always goes- eventually, but it's hunting for fuel. Now I want to replace the hard plastic pipe, which is still in poistion with plastic bags over the ends. But due to the 'U' shape i dont know how to fill it with fuel and get it back on at the pump without the fuel running back!

Motorbikes and tractors never had the problem due to their fuel tanks were higher than the engine, good old gravity! If it aint broke don't fix it!!! Now tractors are bigger than used to be and have thier tanks lower, guess what? yep, more problems lifting fuel
 

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Ops! forgot to ask the question! Looking at the original filter housing, there are 2 knurly finger knobs (can undo with finger rather than tools)one at the bottom side,for draining the water. The other at the top, due you know what this is for? Could it be for priming the filter housing? thanks, regards,Patrick
 

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Discussion Starter · #13 ·
Mitsubishi deserve the credit rather than me - although the unit came from a pretty old car so no doubt they'll have followed the trend & discontinued primer buttons by now ! My (1964) Landrover had a similar feature but I doubt a new Defender offers it.

The 'Peugeot type' of rubber bulb is still available as a 'service tool' from the likes of Halfords & I guess there's no reason why you can't leave one in series after use just like Peugeot do (or more likely did).

From my experience, the most likely causes of air inleak in the original setup are all those patent quick-fit joints and no doubt fitting new O rings to all of them would cure most problems (IF you could get the right size rings anywhere!). Joining a nylon pipe to rubber sounds easy but unless you have a huge overlap air will sneak past the joint.

Afraid I've no idea about the original filter fittings but bleeding the filter body sounds as good a guess as any.
 

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Update update! removed rubber pipe with primer pump, me wonders if air was accumalating in the balloon part and when enough, surged to the injection pump and made it hesitate? just a theory you understand


Reinstalled hard clear plastic pipe, and renewed filter. Topped up with a inverted fairy liquid bottle connected with a short rubber tube from my brake bleeder pushed on to the knurly knob at the top of filter housing- squeezed and squeezed till most of air out and at same time reconnected hard pipe back on to injection pump- phew

The above theory is because when it eventually fired up there was alot of tiny air bubbles heading up the pipe

2 days later, no more air bubbles in pipe so theory a load of rubbish, only done5 miles so cant say if problem cured, however,it feels good to have it back to how it should be

At least the system doesn't now have to over come the necessary extra pressure of the one way valve in the rubber pump,is the there a pressure sensor somewhere? did it not like it??mmm
 

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Discussion Starter · #16 ·
There really shouldn't be a lot of back-pressure from such a one way valve (unless of course you fitted it backwards
).

Once the engine is 'nearly bled' , it's fairly easy to finish the process: slacken connection to no 1 injector (furthest from pump) then turn engine over on starter motor a few times. Re-tighten injector & it should start OK next time. That system doesn't work if you've got a lot of air in system though; you'd flatten battery long before all air gone.
 

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Interesting that Eric, a mechanic told me that with common rail disels, it wont make any difference slackening the injector pipes off- he says just wont work!ok with the old engines tho.
i used to do tractors with just the injectors, worked every time
Going away in the caravan this weekend so should know come Sunday if the problem is cured,or not
 

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Discussion Starter · #18 ·
It certainly seemed to work for me last month.

Suspect your mechanic may be referring to the fact that if there's a lot of air in the system it will just recirculate around the common rail. If there's only a little bit, it can't really help but go the easy way past through the slackened off connector.
 
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