Injector pump

[ditchy]

My 1.5 is struggling to start.

Glow plugs are all fine. And I've tightened up all fuel joints. Big puffs of white smoke as it turns over. It all bleeds o.k on every filter change. Just changed them again at the weekend and the fuel looks fine.

I am wondering if anyone's injector pump shows a small amount of diesel on them. Mine does but It always has. I never bled the top screw on it as I've sheared it in the past with barely any force.

Is this where air is getting in? Or is this quite normal.? I'm very light handed in this area. I apologise for no picture to help and would appreciate any advice and pictures. Thanks

[dccruiser]

I had a bmc 1.5 with a cav pump, my top screw lost its threads and lost fuel pressure through it, i also had one where there was a hairline crack in the casting to the governer screw at the top of the pump, i repaired that with the putty you get for fuel tanks as a quick fix then replaced the pump.

 

 

Rick

 

 

ETA ...Be a good idea to also check the solid fuel lines as they are known to rot through

Edited March 9, 2015 by dccruiser

[pete.i]

If you want to see the sequence to bleed the BMC 1.5 there is a very good You Tube video on the subject here :-

 

 

There is a "don't do" with this video, according to Tony Brookes, who is one of the BMC experts on here so I don't do it . Don't bleed the "top screw" which both posters have said that they have sheared or damaged the threads on this screw. Other problems can occur if this screw is touched so it's best left alone. Other than that the sequence is correct.

 

There is a "workshop manual" for the BMC 1.5 here http://the-norfolk-broads.co.uk/downloads/bmc1500L-diesel-workshop-manual.pdf if that is of any help.

[Troyboy]

When you state glow plugs are fine have you taken them out and cleaned the carbon that gathers in the cylinder head where the glow plug tip sits ? I believe a 11/32 drill bit is the correct size to reamer out the carbon .

I was amazed the difference it made to starting my 1.5 after the carbon was removed although I did also fit new glow plugs . The old ones still worked but the build up of carbon was affecting their efficiency .

[Bee]

Be careful extracting the glow plugs, they are a bit fragile, guess how I know.

[Tony Brooks]

I am not clear as to why Ditchy thinks air is getting into the system, he only says it bleeds OK when the filters are changed. My reading of his post is that he has difficulty starting and his glow plugs are ok BUT he is concerned about a slight diesel weep from an unidentified point on the injector pump.

 

His clouds of white smoke indicates that he has fuel so air in the system is unlikely. That leaves us with a glowplug problem, faulty injectors or low compression. Note what Troyboy says about cleaning the carbon from the injector holes (worry them out, not simply unscrew them). Also note what someone said about teasing the plugs out of the engine. Voltage at the glow plug terminals proves nothing about their operation.

 

If the injectors are streaming jets of fuel rather that producing a fine mist it will be a pig to starts and make clouds of smoke. To make matters worse the injectors have a little "sideways" spray that helps cold starting and these little holes block up.

 

Most ordinary boaters do not have access to a diesel compression tester so paying to have it done should only be considered after all other causes of bad starting ave been ruled out. Check the valve clearances before having it tested.

 

I except the diesel weep is from a joint so make sure the screws that hold the "turret" onto the body are tight and the four screws that hold the steel end section onto the main body. My suspicion is that it is weeping from the throttle or stop spindle O rings or from the glued in idle damper that is part of that top bleed screw assembly. AS the body of that injector pump runs pressurised by the transfer pump such a weep is less likely to be the cause of the poor starting.

Edited March 10, 2015 by Tony Brooks

[ditchy]

Thanks for all the replies. I've arranged a compression test to be carried out. Also how can I check that the injectors are serviceable? It is this a specialist job? Also to add a little more confusion. The glow plugs are fatter than the common 11/64 job. Calcutt tell me this is a latter mid? I'm not sure.

[Tony Brooks]

Thanks for all the replies. I've arranged a compression test to be carried out. Also how can I check that the injectors are serviceable? It is this a specialist job? Also to add a little more confusion. The glow plugs are fatter than the common 11/64 job. Calcutt tell me this is a latter mid? I'm not sure.

 

Late 1.5s, probably manufactured abroad may well use modern glow plugs so not a problem. They are probably BMC 1.8 plugs. Just to be sure please describe where on the engine the injector pump is mounted - it just might be a 1.8 rather than a 1.5. I have not found a definitive answer as to if 1.8 and 1.5 heads are interchangeable.

 

There is a rough and ready way of assessing injector operation but it has potential to cause serious injury so I can not explain it on a public forum and would never do it myself except in the direst emergency. They need to come out and be sent to a diesel injection specialist for testing and probable repair. You may well find that you will be supplied with a set of exchange already overhauled injectors.

[ditchy]

Thanks tony. I think they are 1.8 plugs . Don't know the complete history of the engine but it sys thornycroft( doesn't mean anything though)The pump is as u look at the engine with air filter and exhaust being the rear. It is on the front low down under 1 and 2 injector and to the left of the oiler filter. Above the starter motor. Is it worth me buying a compression tester, the with my findings maybe take the injectors in?

[ditchy]

Thanks for all the replies. I've arranged a compression test to be carried out. Also how can I check that the injectors are serviceable? It is this a specialist job? Also to add a little more confusion. The glow plugs are fatter than the common 11/64 job. Calcutt tell me this is a latter mid? I'm not sure.

[Tony Brooks]

Thanks tony. I think they are 1.8 plugs . Don't know the complete history of the engine but it sys thornycroft( doesn't mean anything though)The pump is as u look at the engine with air filter and exhaust being the rear. It is on the front low down under 1 and 2 injector and to the left of the oiler filter. Above the starter motor. Is it worth me buying a compression tester, the with my findings maybe take the injectors in?

 

 

I think its a BMC 1.8. The 1.5 pump sticks out of the side of the engine (90 degrees to the block) about half way along its length and above the starter. The 1.8 has the pump parallel with the engine block and is fitted right at the front into the back of the timing cover. Thornycroft are just the marinisers, Parts from Calcutt should fit.

Thanks for all the replies. I've arranged a compression test to be carried out. Also how can I check that the injectors are serviceable? It is this a specialist job? Also to add a little more confusion. The glow plugs are fatter than the common 11/64 job. Calcutt tell me this is a latter mid? I'm not sure.

 

This is a duplicate of the post you sent yesterday and was answered. I doubt you will get any other answers from responsible members.

Edited March 11, 2015 by Tony Brooks