First Timer on Possible Injector Problems

[terrylad]

Put it all together and fired it up. Same symptoms, but the engine seemed easier to rev and recover after blowing out blobs of wet black stuff and clouds of blue/white smoke while she stuttered. It got better after 20 minutes and I was able to sustain 2500rpm in reverse (on the mooring) for 4-5 minutes. When it lost it again, it was easier to recover, until I could sustain 2800 for 3 minutes or so. I couldn't keep it up because I kept swinging too close to my neighbors. But I think its just clearing out cobwebs in the exhaust system. I'll take out for a good run tomorrow....

[terrylad]

Since having the injectors tested and reinstalled, I now have pulled the injector pump and sent it to a local diesel workshop for rebuilding and calibrating.

I eliminated the possibility of overheating by testing the thermostat, acid washing the heat exchanger, acid washing the exhaust riser, replacing all the copper washers in the fuel lines, clearing the fuel tank vent, you name it.

I'm hoping that its just a simple matter of varnish or contamination on the IP lifters, or perished gasket washers, something that causes sticky operation, which would account for the baffling symptoms. Will keep posted when I reinstall the IP.

[yachtman]

Have you considered a sticking or damaged inlet valve, or lack of tappet clearance that when hot then floods the next cylinder with combustion gases ?


You could diagnose which cylinder by letting off the injection pipe connection at the injector. the one that leads to running recovery is the guilty one

[terrylad]

Originally Posted by yachtman

Have you considered a sticking or damaged inlet valve, or lack of tappet clearance that when hot then floods the next cylinder with combustion gases ?


You could diagnose which cylinder by letting off the injection pipe connection at the injector. the one that leads to running recovery is the guilty one

I tested it that way while the engine was in failure mode, clacking away, and it seemed to be random between all cylinders, which is why my major suspect is the IP or fuel/air leakage.

In the past, I've had a Volvo MD2B fail on one cylinder in the middle of New England winter while the engine was cold, due to sticky varnish on the inlet valve. A cold engine problem. Diesels don't take to cold weather well IMHO.

[DeepFrz]

If you end up with the same symptoms after installing your IP, check your valve clearances and I would also suggest you have the valve springs tested. Weak valve springs or badly adjusted valves could account for your symptoms. My intuition is leaning towards weak valve springs. Of course my intuition has leaned toward lots of things that weren't causing problems...

[terrylad]

Help! The repair shop has the injector pump in pieces and says the rebuild will cost $800. Claims that the plungers and the valve is worn. They can return it to me in pieces or wait for the go-ahead.

Where can I get a 2nd opinion?

[S/V_Surya]

Originally Posted by terrylad

Where can I get a 2nd opinion?

ROFL. Oh Sorry.

[donradcliffe]

Originally Posted by terrylad

Help! The repair shop has the injector pump in pieces and says the rebuild will cost $800. Claims that the plungers and the valve is worn. They can return it to me in pieces or wait for the go-ahead.

Where can I get a 2nd opinion?

That's about the going rate on injector pump rebuilds, which is why you wanted to eliminate other cheaper possible causes before you decided to do it.

[SkiprJohn]

I've had to bite the bullet on a Bosch injector pump rebuild before. The bill for the 4 cylinder Mercedes pump was higher than $800 about 12 years ago.
It is a high priced item. I'd get them to go ahead on it with a written warrantee.
Make certain you install the exact same orientation that you removed or your timing will be off.
kind regards,

[neptunesjester]

+1 on the going rate. Make sure they warranty the work. I had one rebuilt and after reinstallation the engine would surge at idle. Exhausted all possibilities then took it back to the shop where the fixed it under warranty. Ran like a champ after that.

[terrylad]

Replaced the IP and put the engine together again. I spoke to a Yanmar mechanic about these symptoms and he said that IP problems were very unlikely but fuel pump failure was high on the list for these symptoms, so I pulled it out and opened it up, and sure enough, there was a small perforation. Replaced it and worn fuel pipe and fired it up. Runs like a sewing machine at last.......$930 down the drain, but I feel good about the outcome. She seems to have more power than she ever did.