injector pump possible problem BMW 1.5

[Dovetail]

Think I may have an injector problem on my bmc 1.5.

 

Back story is I stupidly ran out of diesel last week andgot the engine up and running but approx every ten mins it would increase its revs and then settle down only to do it again some ten mins later. Every now and then it would cut out and the only way to start it was to crack a nut on an injector and away she went. I thought it's getting some air in the system although it was not obvious when I restarted the engine. The engine cut out once more and this time thought better change the fuel filter.

 

This is the bit that makes me think perhaps all is not well with the pump. I changed the fuel filter and started to bleed the system and everything is fine upto the top bleed point on the pump as no matter what I try I am not getting any diesel or air out of it nor am I getting any out at the injectors. Everything right up to the side bleed point on the pump has good supply of diesel but nothing through or beyond the pump.

 

I am thinking perhaps this old pump was still going but just and this running out of diesel has only brought forward a failure. Also don't know if regular diesel should play a part as it was all I could get to get the boat up and running again.

 

If anyone can shed any light on it or any suggestions then it will be most welcome.

Sorry not a BMW although that would be nice.

[Tony Brooks]

Assuming the lift pump is OK.

 

Also assuming that you mean that you can not bleed either bleed point on the pump.

 

If you picked up a load of muck when you ran out of fuel and by some means it managed to bypass the filter then there is s strainer gauze under the large hexagon where on of the pipes between the injector pump and filter is connected to the pump. Beware when removing the large hexagon, there may be springs underneath (cant remember). Observe extreme cleanliness and do not use ant rags that leave fibres behind.

 

If you mean that you can bleed the side bleed screw but not the one on the top then are you sure the stop lever on the pump is in the run position. If its definitely in the run position then it sort of indicates the governor valve may have jammed in the no fuel position. There is a load about this in one of the topics in the BMC area.

[Dovetail]

Thanks Tony some good points. I am confident as can be the lift pump is good its not that old and although can go wrong it is pumping plenty of diesel around the rest of the system. Yes I am able to bleed the pump from the side of the pump and good point about about the stop leaver but as the engine cut out itself I never operated the leaver but it's a good point and will check it first before I go any further. I actually had it stick once before and it took me a few goes at trying to start the engine before realising but as mentioned never used it this time but strange things happen. Looking at the manual and yes a filter with spring behind will check that also.

Cheers a great help and a few more things to check.

 

I should add although I can bleed the side screw perhaps the filter is partly blocked and restricting diesel so will check all the same.

Edited December 17, 2014 by Dovetail

[Dovetail]

Well don't ask me how but it's up and running as smooth as I could hope did the checks that Tony suggested but stopped short of getting the filter out of the back of the pump as I decided to many small pieces to drop. I decided to bleed it through one more time as far as I could and just then turn the engine over until the battery ran flat if need be and during this it just started sluggish at first but got going great in the end without any problems. I guess whatever was sticking released and the engine pushed out the air either way I am one happy bunny. The bit that still baffles me still no diesel out of the top vent nut and will investigate this at another time and leave well alone and fill up with diesel sap.

[RLWP]

If find the BMC 1.5 engines an absolute swine to bleed, your story seems very familiar!

 

Richard

[Tony Brooks]

TIP for bleeding reluctant to bleed 1.5s. I have put this up before.

 

Disconnect the fuel pipe that runs form the injector pump close to the engine block to the filter. It does not matter which end. Set throttle to full speed and spin engine on the starter. Fuel will gush out and the engine may start. This often cl;ears stuck air bubble. Then clean up the mess.