engine won't run well after changing oil/filter

[twinboat]

Different diesels return different amounts of fuel.

Of course, any fuel returned to the tank, would empty all the filters, if air is, the only thing replacing it. Fuel is returned after the injection pump.

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[wrwakefield]

Originally Posted by gathem

I changed the air filter, oil filter, the oil, and impeller yesterday. The engine no longer starts.

Not sure about the old oil filter but all the new parts came from volva dealer.

Its an MD30a.

I've done some googling and I'm not sure if the suggestions are applicable.

I was pretty careful not to under/over fill the oi but its not super clear from looking at the dip stick. I used the oil the dealer provided 15W-40.

Any help would be appreciated!

Hi Gathem,

After reading your thread, it wasn't clear if you have a copy of Nigel Calder's "Marine Diesel Engines, troubleshooting, repairing, [etc.]" on board. If not, since it appears you have internet connectivity where you are, you can download the Kindle edition and start troubleshooting following his flow charts.

A worthwhile addition to any [diesel] boat library...

Good luck! Hopefully it is something simple...

[Oceandeep]

If the engine will run for 45 seconds you might try this. Carefully remove one of the fuel lines to one of your injectors. Pull the line out about one inch and try to start your motor. Some fuel and air will come out of the line so have a large rag under it. If the motor starts run it for a few minutes until no more bubbles are coming out in the fuel. Then you can reattach this line. Sounds like you are air-locked. This is the quickest way I know to get the motor running again

[rognvald]

If your system has been bled properly at the secondary filter, injection pump and the injectors and it still fails to run, you might have a partially clogged primary of secondary fuel filter or, as others have suggested a ruptured mechanical lift pump diaphragm. So, to avoid a mechanic: inspect both fuel filters for contamination, pull the lift pump and check the diaphragm, and then bleed your primary filter, the bleed bolt on your secondary filter, the bleed bolt on your injection pump and then give it a try. If it doesn't start, then bleed each cylinder in sequence. Try again. I cannot see how the oil and filter have anything to do with your problem. It's fuel or air related. There are two other possibilities: if you are starting your engine for the first time this year, have you sufficiently advanced your throttle once the engine fired? Secondly, is it possible you left a rag in the air intake over the Winter? Hope this helps. Good luck and good sailing.

[sanibel sailor]

Please someone explain how an allegedly defective pump empties the filter??? Either it pumps or it doesn't. If it don't, your filter will stay full. You got an air leak somewhere between the tank and the empty filter. Period. If the pickup is clogged, it can create enough vacuum to suck air when it had not dome previously. Motor runs 45 secs and your functioning pump sends the excess fuel back to the tank, emptying the filter. Fooling with the pump is as coincidental as the oil change.

[River Cruiser]

All the fuel systems I've worked on the supply pump sucks fuel from the tank thru the primary and then pushes it under pressure thru the secondary. This pressurized fuel then goes to the injector pump and the individual pumps send a metered amount to the injectors. If the supply pump is pulling the fuel out of the primary filter then I would look for a suction leak between the tank and the primary filter itself, I would change the primary filter replacing any orings or seals. I think you can eliminate the supply or lift pump as the problem because it is the only thing that moves fuel from the tank to the injection pump if it was the problem it wouldn't drain the primary. If the hand operated priming pump is separate from the supply pump make sure the plunger is turned into the lock position, if not locked most systems can suck air thru it. Almost forgot make sure all hoses, and clamps and fittings are in good condition and snug.


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[Schrewsburyduo]

Originally Posted by River Cruiser

All the fuel systems I've worked on the supply pump sucks fuel from the tank thru the primary and then pushes it under pressure thru the secondary. This pressurized fuel then goes to the injector pump and the individual pumps send a metered amount to the injectors. If the supply pump is pulling the fuel out of the primary filter then I would look for a suction leak between the tank and the primary filter itself, I would change the primary filter replacing any orings or seals. I think you can eliminate the supply or lift pump as the problem because it is the only thing that moves fuel from the tank to the injection pump if it was the problem it wouldn't drain the primary. If the hand operated priming pump is separate from the supply pump make sure the plunger is turned into the lock position, if not locked most systems can suck air thru it. Almost forgot make sure all hoses, and clamps and fittings are in good condition and snug.


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I want to second that -- this is why I was asking where he was located (i.e. algae maybe) and whether the engine had run no problem for a while before the oil was changed. I had the same problem last year - the engine eventually ran for a minute and then stopped. It was some air getting to the injectors somehow even a bit of air will stop the diesel right away. Turned out it was a conglomerate or issues. I had two filters that were leaking either at filters or hoses. I replaced those with a simple racor, new hoses, and even a new hose to the tank itself - I also emptied the tank and put in fresh new diesel. Then I re-bled the engine - It started right away and never missed a beat since. Do this and see if you won't be pleased with the results.

[Joe Kiernan]

My best suspect here would be that a fuel line from tank to primary is suspect. There has to be NO air suction ingress issues all the way back to tank. The air ingress problem is between the primary filter and the tank, that much is obvious from your filling of the primary, bleeding secondary, running, dying and primary air locked again. Look over all the fittings/lines from primary to tank, tank valve open? A clear piece of fuel hose is a fantastic piece of fuel system inspection tool. You suspect air ingress from tank to primary, put in a clear hose temporarily and run it, if you've got bubbles, find out why and eliminate them, you can always move this piece of clear plastic line around the fuel system (ie. between primary and secondary, after the lift pump to the injection pump, etc to isolate your air ingress issue.

My guess is that you might have leaned, kneeled on a suction line between tank and primary and ripped the line a bit. Remember, fuel suction leaks rarely exibit themselves as a visual, external kinda thing, hence the clear "sightglass" hose.

Joe

[Boatyarddog]

Funny, this guy changed the oil filter and oil and air filter.
So, how did air get into the fuel line?
I don't get it.



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[gathem]

It was air in the fuel system. Changed the seal on the racor primary filter, bled the system (changed the filters too, but I'm pretty sure it was the seal), and it started right up and ran well. Thanks everyone for the input.

[Boatyarddog]

Originally Posted by gathem

It was air in the fuel system. Changed the seal on the racor primary filter, bled the system (changed the filters too, but I'm pretty sure it was the seal), and it started right up and ran well. Thanks everyone for the input.

Confused me there Gathem, in your original post you've clamed to have changed the air filter, oil and oil filter.
I did not see in your post that the fuel filter was changed as well.
Thanks for the clarification.😕


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[Boatyarddog]

Originally Posted by rwidman

There are plenty of things that would keep a diesel engine from starting but changing the oil and filter is not one of them. It would be very coincidental and unlikely that some other part would happen to fail at the very same time that you did what you did.

I'm thinking you accidentally knocked or kicked something loose and didn't notice it.

I suggest hiring a mechanic and telling him exactly what you told us here. Don't make things worse than they are.

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[gathem]

Originally Posted by Boatyarddog

Confused me there Gathem, in your original post you've clamed to have changed the air filter, oil and oil filter.
I did not see in your post that the fuel filter was changed as well.
Thanks for the clarification.😕


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To clarify: originally I did change only the air filter, the oil filter, and the impellor. After it didn't stay running I followed the advice of the Cruisers in this thread and changed the fuel filter, theracor oil ring, then bled the system, and all was well with the world.

[Boatyarddog]

Originally Posted by gathem

To clarify: originally I did change only the air filter, the oil filter, and the impellor. After it didn't stay running I followed the advice of the Cruisers in this thread and changed the fuel filter, theracor oil ring, then bled the system, and all was well with the world.

How did changing the oil, oil filter, and air filter, cause the problem? Of bad running.
So, I know in case this happens to me. Or the problem cleared itself? After changing the fuel filters.
Not sure how that happens.
Were you told why that happened or coincidence?
That's kind of an odd thing.


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[gathem]

Originally Posted by Boatyarddog

How did changing the oil, oil filter, and air filter, cause the problem? Of bad running.
So, I know in case this happens to me. Or the problem cleared itself? After changing the fuel filters.
Not sure how that happens.
Were you told why that happened or coincidence?
That's kind of an odd thing.


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My guess is that it was just a bad o-ring on the racor filter, and doing all of the work changing stuff on the engine was the last straw which caused the air leak.