L100 Engine Failure (fuel related)

[snoopy]

I was just saying how reliable the engine has been and then ...

Something fuel related is wrong. I suspect the fuel filter I was using had failed and crap from the tank got through the system.

I have fuel getting to the pump. It appears that the pump is sucking as the air in my see-through filter disappears and fills with fuel. With the injector pipe off I can see a bit of fuel coming from the fuel-pump output if I kick over, not a massive splurge, just a little and not under any force.

No fuel is coming out the top injector pipe despite kicking over many times. This has been cleaned with compressed air.

The injector has also been apart and cleaned with compressed air (I hope there are three shim washers under that spring or I've lost some!).

Any other ideas? The only thing that hasn't been apart is the fuel pump and that's next.

Cheers,
Andy

[snoopy]

I'm out of ideas.

Confirmed the injector is working, its squiring ok. Fuel pump is good.

Got a bit of mist coming out the air intake which must be the fuel. Nothing smoke wise coming through the exhaust (literally nothing, no mist or anything, just a bit of air and not much at that).

Engine refuses to think about starting.

[andrewaust]

Some of the microscopic holes in the tip of the injector may be blocked, it only takes particles of microns thickness to clog the injector, my advice take the injector to a specialist, or even try and pick a new one up, if it is a clogged injector tip put a finer particle filter on the bike.

You will only get a small amount of fuel from the pump delivery fuel line, it won't be under pressure unless you hook it up to a device that measures fuel delivery pressure, you'd be surprised at the small amount of fuel needed to run these engines.

If compression seems good etc, give the above mentioned things a go, there is a solution you could purchase that you could leave the injector tip in that could dissolve a lot of the material, it wasn't just an ordinary diesel fuel injector cleaner, it was specialist stuff.

Hope this helps a little



A

[snoopy]

Injector is fine though, fuel is coming under pressure out of all four holes.

I'm running out of possibilities.

Can't find the TBC marks on the flywheel either. FS.

[snoopy]

I put a bit of easy start in the air intake and she fired over then died, so it's a fuel problem. I'll replace the injector first....

[BoxerOtto]

check your valve clearances first. just because it has some compression doesnt mean it has all the compression. .006" intake and exhaust cold. do you have your throttle open to allow pump to give full fuel?

[snoopy]

Valves were done yesterday. I'll have the injector pressure checked tomorrow, otherwise it must be the fuel pump. It's pressuring as coming out the injector.

If crap were to get into the fuel pump could pressure be affected?

I've not had it apart before and do not know if its a big job cleaning it out?

[skoleskibe]

half a year ago, my MZ- Yanmar (l100) developed a sporadic problem, starting, normally it would start , but sometimes it wouldnt, if i fave it a faint squirt of eather, it started and ran well. I decided to opt for a new pump, and havent had any issues since, as well as its now possible to run a rather slow idle at around 5-600 rpm opposed to the needed 8-900rpm with the old pump.
Have a go at it, its only about 90€

[snoopy]

Still a no go.

Fuel pump and injector working. Injector sprays a fine mist on kick over.

Valves checked, cams are working properly.

Still no smoke from the exhaust.

I'm stuck.

[penybryn]

check your valve clearances first. just because it has some compression doesnt mean it has all the compression. .006" intake and exhaust cold. do you have your throttle open to allow pump to give full fuel?

Do you have access to a compression tester? Something like a broken piston ring, cracked piston, damaged valve, etc may give the feel of compression but not enough for the diesel to ignite.

[snoopy]

I'v got the exhaust and air filter off now. The fuel vapour is coming out of the air intake while nothing is coming out of the exhaust (air is but no smoke).

[skoleskibe]

seems your inlet valve dont close properly

[snoopy]

I've ordered a new pump and injector nozzle, at half the cost of the original engine!

If that doesn't solve it, I'll post a picture of my face with tears coming down it.

[snoopy]

New pump has solved it. Even though the old one had pressure outside the chamber the 20:1 must have overcome the valve in it.

Should have seen my grin when I saw smoke coming out the exhaust on the first kick.

Also got a new nozzle going in as the Bosche injector service station said mine was 'well knackered'. After 10,000 miles or as supplied by the factory, take your pick.

[coachgeo]

Great to hear Snoopy

[snoopy]

Not quite sorted, down on power probably got 60% of usual top-end. Injector is next..

[andrewaust]

Great to hear your making progress

[snoopy]

Broke down today, same problem with no fuel getting into the engine. Probably the injector has seized. I do wonder though, if an injector seizes will the pressure build up enough to damage the fuel pump?

[andrewaust]

Depending on what's gone wrong the fuel should make it out of the injector return line, it seems like you might have to take a serious look at what fuel filter you are running also.

I cannot be of much help to you at the moment snoopy as you don't know what has really gone wrong also, hopefully it's something simple and easy to fix mate.


A

[coachgeo]

Blockage in fuel line?

Blockage in fuel tank that moves around? (Algae can be famous for this)

Air leak?

[snoopy]

Fuel is coming out the injector but I do not believe the fuel spray is 'misty' enough.

I took the injector to a specialist (Bosche) and he said the spray is shot. He took a shim out (reduced the pressure), ultrasonic cleaned it and said it was a bit better but still very poor. I then bought a new pump installed both and she fired up but ran at only half power. That same day she failed and I was recovered home.

On kick over fuel is coming out the injector, this happened with my old pump as well.

I wonder if the pressure is not enough (guy made a mistake?) and if I should boost the shims a bit?

[snoopy]

I have just swapped the injector and the spray pattern is much better ... but engine still doesn't start and has no smoke either.

Thus it looks like the new fuel pump has failed after a very brief stint. Engine ran badly for less than an hour last week before going into its current state.

I get pressured fuel coming out the injector if I kick down as hard as I can with the governor fully open. Any less effort and I can not (to my eye) see any fuel being sprayed.

Do I need to re-shim the new injector pump to match?
Any other thoughts?

[snoopy]

In addition, no fuel coming out the injector return line indicating that once installed the additional 20:1 compression is overcoming the fuel pump. This is happening with new and old and I presume (not knowing otherwise) that my old injector managed to kill both. Perhaps the pressure was building too much and damaged the valve inside the pump?

[snoopy]

2nd new fuel pump installed and engine started and is running. Rough but getting better, not far off decent enough to ride. How happy am I!!!

[old clunker]

That's great news! Hopefully the engine will run reliably now - after spending lots of money on it!
It's typically replacing the fuel pump and injector in Yanmar clones, that (eventually!) sorts out most diesel engine running problems.

All the best....

[coachgeo]

sweeeeet. Way to keep plugging away at it... ok maybe this time it was unplugging?

[snoopy]

Engine is running well but seems to have lack of 'get up and go', I'm carrying out further testing this morning. Instead its silky smooth compared to before and hovers around the idle much better. I wonder if the fuel timing shims have to be reset with a new fuel pump?

Either way I reckon my original injector was crap right out the box, I'd only done 10k on it and the nozzle was shot. For 'cloners' it would be worth getting the injector to a Bosche service centre where they'll test it for a fiver.

[penybryn]

Hi Snoopy - as I understand it, all the fuel pumps vary a little due to prodution tolerance and the shims are used to set the timing correctly at the factory when the engine is first built. If the fuel pump is replaced, then the timing needs to be checked and adjusted by re-shimming if necessary.
Glad to hear that your own engine is running again.

[snoopy]

Thought so. If I've got this right ... less shims = advanced timing = more power = more knock noise?

If so then that's the way I've got to go. Engine came with 0.5 & 0.1mm shims. I took the 0.1mm off and top speed went from 50 to 54mph. I've now took the 0.5mm of (so 0.4mm reduction) and hoping I've got it back up to the 60 mark. Total guess work of course but I have no other shims to play with.

[snoopy]

I had started another thread but I've now eliminated bad fuel and can confirm the fuel pump, number five, is knackered.

I'm running the proper diesel filter, a big mother, but some sh*t has still got through. What I can say is that the pump progressively gets worse until it fails. In order to have the same power more governor movement is needed until you reach the max and the power drops and/or there isn't enough fuel pressure to start the engine.

With this fifth fuel pump I got longer out of it (Newcastle to Genoa, Italy) where I'm now stranded but with another 12 days off work (could be worse ).

So internally the mechanism that moves on the pump must control something (like a hole?) which is becoming blocked. Has anyone had one of these apart to this level?

I'm TNT'ing another two to Italy for Friday coming...