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BMC Bled but no fuelbeyond Injector Pump


TheSaintlyOne

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A mechanic (My Brother) that knows his way round vehicle engines has attempted to bleed our 1.8 BMC engine and get it running. He followed the correct proceedure and bled the engine all the way but could not get fuel to come out of the fuel Injector pump and hence out of the injectors in much more than a dribble  There seems to be something causing an issue and the BMC will not start Unfortunately time was an issue on saturday and he was unable to stay to troubleshoot if the fuel injector pump is to blame and needs a refurb. Its a new install and fuel is clean and fresh. Engine was bench tested prior to install back at the start of the previous lockdown and ran for a good few minutes after a spray with easy start. But not just on its own 

During the bleed fuel was coming out of every bleed point until they reached the injector pump. Does anyone have any ideas as to what might be causing thisstarting issue or are we looking at a reconditioning our  fuel injector pump.

 

Regards

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I think I would start from square 1 with it. Fuel in tank? filters OK? Then my favourite, a pipe full of fuel or a bottle suspended above the engine  with a plastic tube or something straight to the injector pump. You will need all sorts of bits of tube etc. and its never as easy as it sounds. if it runs then its tank/pipes/filters/lift pump. If it doesn't then I'd be suspicious of the injector pump. Messy but effective.

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Some 1.8s use an electric energise to run stop solenoid, so if this one does, was the ignition on? It would have been on when cranking, but perhaps not for bleeding.

 

If a manual stop control is t being pushed fully off?

 

Some/all have a bleed point on one of the injector pipe unions on the pump. Did he mistake this for one of the low pressure injector pump bleed points?

 

All the small BMCs have a hast habit of trapping slugs of air in the pipework, so how long did he continue bleeding each point AFTER it looked as if all the air was out? I suggest 30 seconds minimum.

 

I think a stuck regulating valve might cause bleeding problems. It, a strainer and springs are under the large hexagon that the inlet     pipe is fixed to on the end of the pump. As long as you keep the parts submerged in diesel and keep any fluffy cloth or paper away from them, its might be an idea ot have a look see.

 

 

Edit: Bee has just reminded me - has the top been off the lift pump, if so is the rubber O ring correctly positioned or has it kinked. Ditto the filter seals.

 

Edited by Tony Brooks
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It uses fuel pressure from the internal transfer pump to push the pumping plungers out but it's modified by the governor valve. I have had governor valves stick when they have water in them. The governor valve is under the turret, containing the throttle and possibly the stop lever(s). Two bolts will allow the turret to lift and take the governor valve out hanging underneath it. Then you can see if its got ant water around it. Again  keep scrupulously clean ad do not use a rag to paper with free fibres.

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16 hours ago, Bee said:

I think I would start from square 1 with it. Fuel in tank? filters OK? Then my favourite, a pipe full of fuel or a bottle suspended above the engine  with a plastic tube or something straight to the injector pump. You will need all sorts of bits of tube etc. and its never as easy as it sounds. if it runs then its tank/pipes/filters/lift pump. If it doesn't then I'd be suspicious of the injector pump. Messy but effective.

Thanks that sounds like a plan to check it out. The fuel and the tank and fuel lines from tank to filter and filter are all new items so we know they are okay.

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17 hours ago, Tony Brooks said:

Some 1.8s use an electric energise to run stop solenoid, so if this one does, was the ignition on? It would have been on when cranking, but perhaps not for bleeding.

 

If a manual stop control is t being pushed fully off?

 

Some/all have a bleed point on one of the injector pipe unions on the pump. Did he mistake this for one of the low pressure injector pump bleed points?

 

All the small BMCs have a hast habit of trapping slugs of air in the pipework, so how long did he continue bleeding each point AFTER it looked as if all the air was out? I suggest 30 seconds minimum.

 

I think a stuck regulating valve might cause bleeding problems. It, a strainer and springs are under the large hexagon that the inlet     pipe is fixed to on the end of the pump. As long as you keep the parts submerged in diesel and keep any fluffy cloth or paper away from them, its might be an idea ot have a look see.

 

 

Edit: Bee has just reminded me - has the top been off the lift pump, if so is the rubber O ring correctly positioned or has it kinked. Ditto the filter seals.

 

Its definitely a manual stop and it was checked  but we are considering switching  upgrade to a automatic lift pump. Will defo check your other suggestions but I think (not being mechanically  minded myself) that the fuel pump itself was working. There just seems to be a blockage from the fuel pump side and beyond into the engine. I know my boat partner Paul Davis had it running on the bench before install but could only start it with easystart and then it ran for a few minutes. We had a distance issue so Paul was largely operating on his own 

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That still sounds like air in the injection pump to me, so something else to try.

 

There are two pipes connecting the filter to the injector pump. One with an inward pointing arrow and one outwards. The pipe from the mounting flange end of the pump should run to the into the filter arrow and have a valve union between itself and the filter. Make sure that valve is clean. Remove the pipe from the valve and direct it into a can/milk carton. Full throttle and get someone to crank the engine. Fuel will spew from the pipe and it often shifts a stubborn slug of air from the pump.

 

The lift pump may well appear to work but if it sucks more air into the fuel than the 0.5mm hole in the filter head banjo can return to the tank the injector pump will air lock. So, make sure the cap  eal is in good order, make sure the pump cap has not been squashed, make sure you have new soft washer on the cap bolt (I would use nylon or fibre) and make sure the diaphragm is not punctured but that usually leaks fuel from the tell-tale hole or into the sump.

 

To test the pump, take both pipes off it and in turn cover one hole with your thumb. The spin the engine or prime the pump holding your thumb in place. One side should old vacuum for at least 30 seconds and the other pressure for the same time. If they don't then something is probably leaking on the pump.

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5 minutes ago, Tony Brooks said:

That still sounds like air in the injection pump to me, so something else to try.

 

There are two pipes connecting the filter to the injector pump. One with an inward pointing arrow and one outwards. The pipe from the mounting flange end of the pump should run to the into the filter arrow and have a valve union between itself and the filter. Make sure that valve is clean. Remove the pipe from the valve and direct it into a can/milk carton. Full throttle and get someone to crank the engine. Fuel will spew from the pipe and it often shifts a stubborn slug of air from the pump.

 

The lift pump may well appear to work but if it sucks more air into the fuel than the 0.5mm hole in the filter head banjo can return to the tank the injector pump will air lock. So, make sure the cap  eal is in good order, make sure the pump cap has not been squashed, make sure you have new soft washer on the cap bolt (I would use nylon or fibre) and make sure the diaphragm is not punctured but that usually leaks fuel from the tell-tale hole or into the sump.

 

To test the pump, take both pipes off it and in turn cover one hole with your thumb. The spin the engine or prime the pump holding your thumb in place. One side should old vacuum for at least 30 seconds and the other pressure for the same time. If they don't then something is probably leaking on the pump.

Thanks will give that a try I know paul and my brother (who is als a Paul) are paying close attention to this thread as well 

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There have been a lot of threads on CWDF about bleeding bmc 1.8s, do a google search and you get a lot, or use the search function at the top of this page.

There is at least one bleed screw on the side of the injection pump ( I think), as well as all those o rings etc on the fuel filters and the lift pump. It may be worth starting from the tank, and working your way forward.

 

ETA, if your brother is a car mechanic, I suggest he could do worse than ask around where he works, if anyone had worked on an old Sherpa van, the engine was basically the same.

Edited by Stilllearning
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1 hour ago, Stilllearning said:

There have been a lot of threads on CWDF about bleeding bmc 1.8s, do a google search and you get a lot, or use the search function at the top of this page.

There is at least one bleed screw on the side of the injection pump ( I think), as well as all those o rings etc on the fuel filters and the lift pump. It may be worth starting from the tank, and working your way forward.

Have done now thankyou seeing alot about the extra nleed point on the filter and the extra bleeding time required to push all the air through

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Bleed point 1.- large hexagon on top of the filter (5/8AF?)

Point 2 - 8mm bleed point on side of the pump.

Point 3 if needed as it is in this case 8mm bleed point between the throttle and stop levers.

 

Point 4 on some 1.8s to save undoing the  injector unions - 8mm bleed point in the banjo bolt securing an injector pipe adaptor to the pump, but I would rather undo the injector unions so i ca see fuel from all pipes.

 

 

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