BMC 1500 break down.

[Christianonthecut]

Hi all,

 

Need help.

 

We were cruising along at full tilt on the shroppie when the BMC decided to shut down.

 

After a little drama I got the boat over to the tow path and moored it up.

 

Time to investigate. Initial thoughts were that we had ran out of diesel. But the tank is still 1/4 full.

 

A friendly passer by suggested that the fuel filter could be blocked and fortunately I have a spare so quickly fitted this. The original filter was full of fuel and made a right mess everywhere.

 

So new filter fitted and time to prime. Only problem is I'm not sure how to bleed the filter housing and fuel pump.

 

I tried pumping the lift pump but it didn't seem to be doing anything. So I disconnected the union that feeds the filter from the lift pump and began to pump it but nothing was coming out. I then spoke to somebody who suggested I turn the engine over slightly until there it resistance on the pump action. Sure enough fuel started to pump through albeit very sporadically and not much.

 

So I undid the big bleed screw on the filter housing and began to pump it and air bubbles started to come out, but I haven't been able to get anything like a steady flow of fuel out of it.

 

It's like the fuel tank is empty, but as I say it is definitely 1/4 full.

 

Thoughts, ideas and info to bleed the pump would be appreciated. We are stranded at present!! Help.

 

Nice view though.

[Tony Brooks]

Sounds to me like out of fuel or an air leak in a pipe/union. The fuel pipe should not draw from the bottom of the tank. I have known tanks be empty with more than 4" of fuel in them. Yours may be even further from the bottom or if the pipe enters the top of the tank it may have split part way up.

 

Some supply pipes have a strainer on the end in the tank. This can clog, try blowing back into the tank.

 

It is worth putting a gallon or two of fuel in the tank, road diesel will be fine, to see if it helps. Once we rule out being out of fuel we can go into the bleeding.

[Christianonthecut]

Hi Tony,

 

Thank you.

 

Will get some diesel in the morning and report back from there... had enough today.

[Christianonthecut]

So I should have left everything until tomorrow but decided to investigate further. the lift pump seems to be pumping diesel around now.

 

I bled the filter, then undid the 8mm screw on the side of the fuel pump and bled that off, then undid the bleed screw on the top and bled that off, then tightened it up and managed to snap the stinking thing off!!

 

Double help.

[Steve 210859]

Hi

 

Sorry to hear of your woes. If you send me your email address by text to 07184530679 (my number) I will email you a link to the BMC 1500 Diesel Operators Manual PDF if that will help.

 

It is possible to bleed at each injector pipe union if you know what youre at and can set your engine position during the process.

 

Steve Williams

BSS Examiner PIN 614

www.iwabss-limited.co.uk

[bizzard]

If the bleed screw spanner head snapped off (when tight) it shouldn't leak, but could depend on the type of bleed screw.

Edited August 25, 2013 by bizzard

[Christianonthecut]

It leaks. I have unscrewed it and cleaned it up and sealed it with some jb weld. Only stuff I had on hand. will refit in the morning it shouldn't leak, but I won't be able to bleed from there again.

 

Any advice for bleeding from injectors?

 

Gotta say I'm kinda worried it might be a loss of compression. Anybody have experience of headgasket blowing on the 1500?

 

No water in oil, no overheating, no loss of coolant and all still clean? It lost power and then died all within seconds. It has always been a good starter and runner up until today.

Edited August 25, 2013 by Christianonthecut

[EmmaB]

Manual:

http://www.the-norfolk-broads.co.uk/downloads/bmc1500L-diesel-workshop-manual.pdf

[Bill MBS]

It is possible the head gasket can blow between 2 cylinders

 

check you have fuel to the injetors first. Slacken all injector pipes at the injectors, make sure stop is in and give it some throttle and crank the engine over, you should get fuel at the injectors.

[Christianonthecut]

Thanks for the link to the manual.

 

There seems to be fuel at the injectors.

 

I haven't tried to start it yet as I haven't been able to get anymore fuel. Seems crazy when there's about 80 litres in the tank.

 

We had just filled the water tank before it conked and the angle the boat sits in the water had changed, so this may have caused a starvation issue if the tank pick up is not very close to the bottom for whatever reason.

 

There's a garage that sells red over the road, but not open until tomorrow!!

 

The bleed screw is sealed although won't be bleeding anything off again, hope I can work around it. I've connected the starter battery to the domestics and solar is giving it a good charge so should have plenty of cranking power.

 

Will the system self bleed if it cranks over enough?

[Tony Brooks]

No, it will not self bleed unless you are exceptionally lucky - not worth trying.

 

Ah well - how many times have I written on here about NOT using that top screw for bleeding and leave well alone.

 

I trust you kept bleeding from the pump for at least 30 seconds after you thought all the air was out. BMCs can trap air in the pipes.

 

As far as bleeding the injectors are concerned loosen all the large union nuts about half a turn or so and crank the engine (stop in run position). When they drip or spit tighten them up. Being a 1.8 it should have a bleed screw on one of the injector pipe unions on the injector pump that you could use instead of undoing the injector unions but in view of your experience so far I suggest you stay well away from it - the union nuts on the injectors are far, far more resistant to snapping off.

 

No one said you had run out of fuel, I just pointed out that the symptoms as presented strongly suggested that and explained why. Always try the simplest things first.

 

Despite what it says in the manual you will almost never need to use that top bleed screw so as long as it is not leaking it will be fine.

[Christianonthecut]

So many differing opinions on effectively bleeding this 1500 engine.

 

Some say it self bleeds, the manual says to unscrew the top screw, still others say not to touch it.

 

Fuel is on its way, I will report back shortly.

[EmmaB]

I've just done mine. Bleed the side bleed screw on the injector pump (don't crank) using the lift pump. Much longer than you think until flowing slowly but freely without bubbles.

 

The remove one by one the nuts joining pipe to injectors and crank until each one spurts fuel in regular spurts.

 

Then it *will* start. If the glowplugs are at all iffy use a blowtorch in the air intake.

Edited August 26, 2013 by EmmaB

[Tony Brooks]

 

 

No need to remove those injector nust, half a turn or so will suffice.

[Tony Brooks]

Any news yet?

[Christianonthecut]

Sorry about the delay.

 

managed to get it running with more fuel and a good bleed off. It was running better than ever, my bodge and faff about with the top bleed screw has ever so slightly increased the idle speed and the boat runs at a better speed now at idle. It was either too slow or too fast before, but perfect now.

 

We moored up last night about 3 miles from where we broke down. No internet or phone signal though

.

I checked everything over and then an early start this morning.

 

Got about 1/2 a mile this morning and it stopped once again. Another bleed off ensued using the 8mm on the side of the pump and cracked 2 injectors and off it went again. Got a further 2 miles and the same thing again. This time I just bled the 2 injectors at full throttle on the starter and away she went. Same again 2 miles after this and we managed to limp into Norbury Junction to get some more diesel.So the tank is over 1/2 full now.

 

This time we left Norbury and kept going for nearly 7 miles all at just a touch over tick over. Less than walking pace, but it kept running and would have done all the way back, but in order to see if the extra fuel had fixed the problem I gave it some throttle on the home straight and it immediately died.

 

Got it back to the home mooring at tickover after a quick bleed on the 2 injectors...Thanks God!!

 

 

Thoughts and opinions appreciated. I'm thinking lift pump maybe. There is always fuel at the injectors when I bleed at full throttle, there is never a delay in delivery after it has stopped.

 

Thanks again everybody for all of your help.

Edited August 27, 2013 by Christianonthecut

[Tony Brooks]

This now sounds as if air is getting into the system and building up until it stops the engine. However on a BMC this should not be possible unless you have a really loose pipe connection or pre-filter/water trap problem. Most BMC with hydraulic DPA pumps usually rev up just before stopping when they suffer fuel starvation.

 

Any small air bubbles that manage to form in the supply pipe will collect in the top of the engine filter. They then bleed back to the tank via a 0.5mm hole in the side of the 5/8 AF banjo bolt that secures the injector and return to the tank pipes to the filter head. Make sure the return to the tank is actually there and then take the bolt out and make sure the small hole is clear. I have known them to block. If you do not spill any fuel out of the filter you should not have to re-bleed the system, but mat have to.

 

I know you said that you changed your fuel filter but good practise says there should be at least a water trap of some sort between tank and lift pump. You may or may not have one of these, I simply do not know. Follow the pipes between tank and engine. if you find anything even remotely like a filter that will be the thing. You need to turn the fuel off, strip it and clean it. Report back with a description of what you find in there in case you have diesel bug.

 

It is always a possibility that you may have a pinhole in the lift pump diaphragm but it is not that common, when they do pinhole they often as not leak fuel into the sump and/or out of a breather hole in the base of the pump. However it would be worth removing the domed cap on the pump and cleaning the strainer and sediment trap you find in there. once again report back. DO NOT try to take the rubber seal out of the cap, if you do you may never get it back in again because they swell. Make sure the soft washer on the bolt that holds the cap on is still soft and in good condition. If not renew it. Also make sure the top of the dome has not gone concave. If it has you can carefully hammer it back to flat on (say) a stern dolly or some such. You will have to rebleed the system.

 

I think I can explain the increase in idle revs. That top bleed point screws into the idle stabilisation damper (you will see the bleed is fitted into a bolt head with a lock nut below it). In messing with that bleed point you have altered the adjustment and an increase in idle revs can be the result. If you are happy do not touch it again, although the manual gives instructions for the adjustment.

 

Please bear with us and do not go buying new bits without a proven good reason. This is an ongoing process of diagnosis.

 

It may well be worth undoing a fuel pipe union so you can try blowing back into the tank. If you do have bug the strainer that may be on the fuel inlet could be blocking with muck so blowing back may temporally cure it.

 

 

Edited to add:-

 

I did not tell you how to test the lift pump because it involves undoing unions and those lift pump unions can be a bit of a beast to get back it without cross threading them, but if you want to test it:-

 

Undo both unions and pull clear of the pump.

 

With the stop control in the STOP position get an assistant to spin the engine over while you hold your thumb firmly over the outlet. After a few turns stop cranking but keep you thumb in place. The pump should hold pressure for at least 30 seconds.

 

Now repeat with the inlet except this time it should create a suction. Although it is said it should hold vacuum for 30 seconds I would not worry too much if it was a bit less AS LONG as it held pressure properly.

Edited August 27, 2013 by Tony Brooks

[Christianonthecut]

Hi Tony,

I just wanted to say that the engine does rev up just before it cuts out. By the end I could anticipate when it was going to die because of the flare in revs. I even managed to avert the engine stopping on the final stretch by lowering the engine speed when I heard the revs start to increase. Backing off the throttle a touch was enough to keep it running.

There is no water trap or filter before the lift pump and the return line to the tank is there and the banjo on top of the filter housing is clear.

Thanks

[Tony Brooks]

I was not on about the big hole up the middle of the banjo but a small one in the side, easy to miss if you do not know what you are looking for.

Is there a tap on the return at the tank end and if so is it turned off? If so turn it on and try again.

 

Once you are sure there are no air leaks into the supply pipe than it has to be fuel starvation. I would suspect something nasty in the tank before the lift pump, but give the lift pump a test.

 

If you look at the return from injection pump to filter head (the one with an arrow on the head pointing into the filter) you should see the pipe screws into an loner hexagon "adaptor" . the adaptor is in fact a one way valve and when these jamb shut or open they can cause all sorts of odd symptoms. maybe worth a check.

 

The other pipe between filter and injection pump (the feed pipe) terminates on a large hexagon. If you remove the pipe and unscrew that hexagon - take great care about cleanliness and the spring loaded parts below it! - there is a plastic strainer. make sure this is not blocked, However check the lift pump strainer and sediment trap first. Without a pre-filter/water trap that is the first thing that collects the muck.

 

If it is dirty please post a photo and describe the "feel" of the dirt. We need to establish it its just dirt or bug.

[Christianonthecut]

Thanks Tony, I will check everything you listed tomorrow.

 

I just emptied some of the remnants from the old filter and it seems to have lots of dirt and muck in it. It just looks like plain old dirt to me.

 

Not sure what a bug looks like.

[Tony Brooks]

Feel it. If its gritty its not bug, but if its slimy it may well be. If it go into the filter then there is a good chance the lift pump strainer is blocked (some replacement pumps do not have a strainer but you have to look under the dome to see).

 

Bug can be any colour from black, through grey and brown to almost reddish. It tends to make the fuel go cloudy as well. I have even seen it as an almost clear waxy substance.

Edited August 27, 2013 by Tony Brooks

[Christianonthecut]

I took the lift pump dome top off and found the strainer more or less completely blocked with crud. It wasn't slimey, just standard dirt and believe it or not dog hairs!!

 

So I cleaned it out, but noticed that the lift pump is leaking really badly and not from either of the pipe unions.

 

Next, I took the banjo bolt off the filter housing and blasted the small hole on the side out with some carb cleaner, but it was already pretty clean.

 

Last of all I took the big nut on the filter fuel inlet of and took the gauze filter, spring etc out and gave all of that a good clean out. It was also full of dog hairs...no idea how they made it through both filters to that point.

 

There was some dirt, but a blast out with carb cleaner had the whole lot is like new again. Reasembled and it's ready to prime and start although I haven't done so yet because I haven't tested the lift pump as the fuel shut off valve is stuck fast and I can't turn the fuel off. I made a mess everywhere opening the top of the lift pump.

 

I also found another problem albeit not fuel related.

 

Whilst scratching around by the lift pump I found a sheared bolt underneath the engine and realised that it was from the engine mount.

 

A bit of investigation has revealed that the bolt holding the mount to the side of the block is the only one still in place, and the 2 on the front plate are both missing.

 

On the alternator side, the bolt in the block has sheared off(although has been like it for some time as the engine repaint a few years ago confirms that the bolt was not present at that time) and the 2 bolts holding the mount to the front plate are the only ones in place.

Edited August 28, 2013 by Christianonthecut

[Christianonthecut]

Just managed to free the fuel tap and tested the lift pump. It passed both the pump and vacuum tests outlined earlier without problem, but does still seem to be leaking from somewhere. Although again, not from the unions.

[bizzard]

Just managed to free the fuel tap and tested the lift pump. It passed both the pump and vacuum tests outlined earlier without problem, but does still seem to be leaking from somewhere. Although again, not from the unions.

Probably leaking from the domed top hat rubber sealing ring or its holding down screw. There should be a small fibre or neoprene sealing washer under that screws head. You could also gently check the ring of screws for tightness that trap the diaphram between the two body halves.

[Christianonthecut]

The sealing washer is still in place, I will try tightening the screws around the body. Thanks Bizzard.

 

Any thoughts on these sheared bolts? Ever heard of then going like that before?