Md2020 issues...

[mattnj]

So my md2020 doesn't like starting....loads of cranking needed, lots of white smoke and it fires and runs slowly rough ish for about 30secs or maybe 60 with starter....then eventually gets going and runs fine all day (seems to have plenty of power and idles ok with no smoke once warm)

Coolant and oil ok (clean)

I took head off, new valves, lapped in (a couple had some minor corrosion but barely noticeable) obviously new head gasket, stem seals, glow plugs are fine and glow red... New injectors.... Back together... The same...

So I've now taken pistons out, and again, all looks ok, measured bores all well within spec, no taper or marks... Obviously not "new" but I've see a lot worse on engines that run...

I will hone and it will go back together again with new piston rings (old ones were on the bottom end of thickness tolerance)

What else have I missed!

Injector pump is about the only thing left, that I haven't touched.... but it runs a1 when started so surely can't be that?

I've got this feeling it's going to go back together and be the same...

Oh and just to add this just suddenly happened...hasn't been getting slowly worse...just 1 day it didn't start....the day before it was fine on the key...

 

[Just_sayin']

So ? just a bit of advice.

Don‘t keep cranking an engine that won’t fire without closing the water intake.

That may be inconvenient but as you can fill the exhaust system with water … next stop the cylinders … it’s the lesser of two evils.

 

[mattnj]

So ? just a bit of advice.

Don‘t keep cranking an engine that won’t fire without closing the water intake.

That may be inconvenient but as you can fill the exhaust system with water … next stop the cylinders … it’s the lesser of two evils.

She's out on the bench at home with a makeshift water supply....don't worry got that bit covered...

 

[VicS]

So my md2020 doesn't like starting....loads of cranking needed, lots of white smoke and it fires and runs slowly rough ish for about 30secs or maybe 60 with starter....then eventually gets going and runs fine all day (seems to have plenty of power and idles ok with no smoke once warm)
Coolant and oil ok (clean)
I took head off, new valves, lapped in (a couple had some minor corrosion but barely noticeable) obviously new head gasket, stem seals, glow plugs are fine and glow red... New injectors.... Back together... The same...
So I've now taken pistons out, and again, all looks ok, measured bores all well within spec, no taper or marks... Obviously not "new" but I've see a lot worse on engines that run...
I will hone and it will go back together again with new piston rings (old ones were on the bottom end of thickness tolerance)
What else have I missed!
Injector pump is about the only thing left, that I haven't touched.... but it runs a1 when started so surely can't be that?
I've got this feeling it's going to go back together and be the same...
Oh and just to add this just suddenly happened...hasn't been getting slowly worse...just 1 day it didn't start....the day before it was fine on the key...

Double check the operation of the glowplugs.

You dont say how you tested them. If that is just a "bench test" to ensure that they are OK check that they are being energised during preheating and cranking.

.

 

[mattnj]

Double check the operation of the glowplugs.

You dont say how you tested them. If that is just a "bench test" to ensure that they are OK check that they are being energised during preheating and cranking.

.

Removed them, tested individually...then connect a wire manually to the busbar for testing...

Think I'll order a new lift pump just incase!

 

[xyachtdave]

Judging by the work you're doing you're further up the mechanical food chain than me!

I have a 1995 MD2020a, when it needed cranking a bit more and ran rough for a few seconds when cold I fitted 3 new glow plugs. The result was like fitting a new engine but only cost about £80.

 

[Daydream believer]

Glow plug relay. Mine fails every 1000 hours

 

[peteK]

Judging by the work you're doing you're further up the mechanical food chain than me!

I have a 1995 MD2020a, when it needed cranking a bit more and ran rough for a few seconds when cold I fitted 3 new glow plugs. The result was like fitting a new engine but only cost about £80.

The glowplugs are only around £7 on ebay,used in other engines beside marine.NGK Y107v is the type.

 

[VicS]

Removed them, tested individually...then connect a wire manually to the busbar for testing...

Think I'll order a new lift pump just incase!

Dont buy a lift pump without some diagnostic testing......... can you raise whatever you are using as a fuel tank so that the engine is gravity fed.
Can you try an outboard engine type of fuel bulb

White smoke most likely unburnt fuel suggesting no problem with fuel supply but does point to glow plugs or the power supply to them.

 

[xyachtdave]

The glowplugs are only around £7 on ebay,used in other engines beside marine.NGK Y107v is the type.

Those barstards at Volspec have done me again...grrrrr!

 

[mattnj]

Dont buy a lift pump without some diagnostic testing......... can you raise whatever you are using as a fuel tank so that the engine is gravity fed.
Can you try an outboard engine type of fuel bulb

White smoke most likely unburnt fuel suggesting no problem with fuel supply but does point to glow plugs or the power supply to them.

I've diagnosed it to death....
Glow plugs glow red after about 12secs...it's not those...

Lift pump doesn't work manually anyway (never has) but works ok when off the block....

It's all apart now...new rings going in...

 

[mattnj]

The glowplugs are only around £7 on ebay,used in other engines beside marine.NGK Y107v is the type.

Thanks....will replace those too...

 

[Daydream believer]

I've diagnosed it to death....
Glow plugs glow red after about 12secs...it's not those...

Lift pump doesn't work manually anyway (never has) but works ok when off the block....

It's all apart now...new rings going in...

The glows may be ok themselves but whilst you may have tested them via a 12 v cable out of the head have you tested them via the relay. Whist in the head?I suggest swopping the starter relay with the glow relay and see if the starter turns ( the two relays are identical) if the starter does not then turn under load it is a simple 5 pin relay issue

 

[mattnj]

The glows may be ok themselves but whilst you may have tested them via a 12 v cable out of the head have you tested them via the relay. Whist in the head?I suggest swopping the starter relay with the glow relay and see if the starter turns ( the two relays are identical) if the starter does not then turn under load it is a simple 5 pin relay issue

I don't/didnt have the loom connected as its running on bench, so for glow plugs its a flying lead from busbar directly onto the battery.....then to start its another flying lead directly onto the solenoid...

thanks for everyone's input so far, I will report back if/when i get it fixed... if the new piston rings dont fix it then im stumped...

 

[Daydream believer]

I don't/didnt have the loom connected as its running on bench, so for glow plugs its a flying lead from busbar directly onto the battery.....then to start its another flying lead directly onto the solenoid...

thanks for everyone's input so far, I will report back if/when i get it fixed... if the new piston rings dont fix it then im stumped...

Sorry had not picked that up from earlier posts