Author Topic: Troubleshooting Possible Injector Issue (Read 11779 times)

sailprincess · « **on:** January 14 2018, 19:01 »

We're on a Bav 40, 2002 model which has a Volvo Penta MD2030 engine. It has about 1100 hours on it. New fuel pump & mixing elbow 3 yrs ago. Recently, we changed the primary and secondary (racor) filters. We ran her for about an hour at the dock and all was good. Took her out for about 7 hours- all good.... then the RPMs took a dive, shot back up, back down, then the engine died. We figured air was in the lines or something so we bled them several times and kept trying. She starts up just fine, then after 3-6 mins, hesitates and dies. Couldn't give it any throttle either- no more than 2k. Checked all connections for air leaks and all seemed good. Noticed one injector leaking just a tiny bit, but we didn't think enough to cause this issue. Thinking perhaps it was a clogged injector from possible tainted fuel in the filter when we changed it. Changed the secondary filter again. Still same issue. Pulled the injectors and had them tested and cleaned- one was dirty. Got new gaskets and reinstalled the injectors and slight knocking noise has now started. We are thinking perhaps a bad injector still, but aren't sure. We are in Mazatlan, MX and there are no certified mechanics here so we are kind of on our own. Any thoughts? Video attached of the engine running so you can hear the noise.

Ziffius · « **Reply #1 on:** January 14 2018, 20:44 »

Have you the standard bavaria fuel cock - T handle type. Mine had very similar symptoms caused by gunge trapped in the fuel stop cock restricting fuel flow.

Spirit of Mary · « **Reply #2 on:** January 14 2018, 22:33 »

To me it looks like a (partly) blocked fuel feed line or filter or fuel cock as already suggested. I had a similar problem with an older VP engine. The problem was blocked pre filter due to dirty,jelly fuel. I had to clean the fuel tank.

sailprincess · « **Reply #3 on:** January 15 2018, 16:02 »

Thank you- I will check that! Do you think a blockage there would cause that tapping sound though?

Lyra · « **Reply #4 on:** January 15 2018, 19:50 »

Tapping sounds to me more like valves gap (my 4000 hrs engine makes similar noises when it is cold which disappear after several minutes of operation).

It is possible that when you changed the primary filter some loose dirt got caught in the lifting pump (the one between the primary and secondary filter) - it has small disk type valves, and if something gets stuck in them they do not function properly and fuel does not flow well which can explain bursts of operation or no operation at all.

Craig · « **Reply #5 on:** January 15 2018, 23:29 »

Ziffius is probably correct about the fuel blockage issue.

It is more likely that your Fuel Off/On switch will get clogged with "Diesel Bug" than your filters. Install an in-line strainer ( large mesh type, not another filter) in the fuel line before the off-on switch to collect the large size "Bug" deposits but not block the line.

The tapping sound is much louder than the sound usually associated with valves, but this may be to do with your recording. Definitely get the valve clearances checked. Taking the boat for a run at high revs should give an indication if you have an injector issue.

Craig
"Shirley Valentine"
Gold Coast
Australia

JEN-et-ROSS · « **Reply #6 on:** January 18 2018, 09:15 »

It's difficult to judge from a recording, but you can hear the tappets happily chattering away normally in the background.
Also a bad/loose tappet would create a regular 'knock', as would big/small ends. This knock is irregular and sounds lighter in nature, more like something external, possibly a control cable/fuel pipe whacking off a bulkhead or engine block. Or even a loose/damaged engine mount..........Just a thought

Salty · « **Reply #7 on:** January 18 2018, 10:49 »

It might sound daft, but is your fuel valve open? Several of us including myself have motored off, and have run our engines for several hours only to discover at some point that the engine has stopped and doesn't want to start again. Typically the engine will run happily at low revs, but then refuses to increase just when you want a bit of extra grunt. A couple of winters back while taking my boat to a yard some thirty five miles away for winter lift out, we ran all day under motor, about six hours or so, stopped and moored overnight, then next morning restarted to head in to the hoist and the engine died just in time for me to turn away from the hoist and get back into deeper water. A hurried search revealed that the fuel valve had been left shut from the previous morning. Now it gets left open all of the time !!
In regard to fuel injectors and tappets, I asked the yard engineer to check the tappets this winter, which he did, and then to take out the injectors and have them checked to ensure they were working properly with the right fuel spray pattern etc. He said if I was not experiencing any problems with the injectors, that I should leave them well alone. In other words if they were not broke, then don't fix them. Fixing them apparently, was likely to result in other problems that may not have been there at the start.

Clivert · « **Reply #8 on:** January 18 2018, 14:54 »

I had a similar problem on our 34 going to Poole.
I checked and drained the water separator and this cured the problem.

Impavidus · « **Reply #9 on:** January 20 2018, 19:58 »

Def sounds like fuel starvation. Possibly water in fuel. I would work my way back to the tank from the secondary filter, blowing the lines out as you go. (foot pump or bicycle pump works well) first stop primary filter, then lines to fuel tap, the tap to tank.

Regards Ant.

sailprincess · « **Reply #10 on:** March 20 2018, 23:21 »

Replaced all fuel line hoses (except the return line) including replacing the fuel shut off valve (as I understand that they are prone to issues) We have a ball-valve in place now. Testing the tank vent to ensure it wasn't clogged. Engine is still stalling after about 20 minutes. Checked the pick up tube, we can't see any holes. Tightened ALL fittings. Blew through pick up tube, doesn't seem clogged. Took sample of fuel, it is not dirty, nor is the racor filter. The engine runs fine through the racor to a bucket. Any suggestions? Also note that the injectors have all been cleaned and we installed a new lift pump to rule that out as well.

Impavidus · « **Reply #11 on:** March 21 2018, 08:56 »

Craig.

Going back to your video it still sounds like fuel problem. I assume you have checked all the joints on the feed line and that the O rings on the filters are ok? Did you replace the primary with a Racore or added it in line with the primary? If so did you change the small O ring on the long bolt that holds the primary together? They often get overlooked. Have you checked the lift pump? some have a wire mesh filter in them. Cleaned it out? Not sure if you are saying you have blown through the return line fully back to the tank?
I have seen filters where the rolled edges of the canister are not sealed. May be worth a second look.

The sound I am hearing is an engine searching for fuel. If it starts ok and runs for a while then you have compression, air and a good spray. As you say its then stalling out after a while something is changing as the engine gets warm? Perhaps a metal joint near the engine?

If everything else is definitely ok then I would suspect the injector pump. Probably the governor as thats what determines the fuel feed to the engine. However the engine starts so it kind of rules that out.
If, as I read your posts, the problem originates from changing the filters (?) I think thats most likely to be the issue. Air being drawn in by either the lift pump or the injector pump. Either in the fuel line or at the filters.

Hope thats of some help.

Ant.

Odysseus · « **Reply #12 on:** March 21 2018, 09:41 »

I am often asked to help people with engine issues and my first response is keep it simple, these engines run cements mixes for years, they are bullet proof if looked after.
If it starts and the engine sound ok, then it stops or hunts after a period of time it's probably fuel. The engine fuel pressure pump is a significantly engineered product, failure is unusual, injector can leak but the engine will run no issue.

Simple checks have been recommended however my primary check it to blow back through the fuel lines until you hear bubbles in the tank, these should be of sufficient volume and noise to establish free flow of air through the system. I have found that there can be a partial blockage that you are aware of when blowing back as there will be a significant back pressure.

The 2 week links in the chain are the pick up pipe in the tank gets blocked or partial blockage.

The fuel shut of valve is a gas valve with very small holes allowing the fuel through, it gets blocked easily. Fit a clear pre filter to it.

Hope this helps

Odysseus
Beg 38

After this you can start to look into other parts of the engine.

Impavidus · « **Reply #13 on:** March 21 2018, 11:09 »

Bill, I agree. KISS :-) as we used to say in REME.

The fact that the engine starts and runs points to something simple. I would not assume that the new filters are good. Or they are sealed. I have had both oil and derv filters spanking new out the box leak.

Good luck Craig hope you find the problem.

Ant.

sailprincess · « **Reply #14 on:** March 21 2018, 17:44 »

Thanks for the feedback everyone. To clarify- the knocking sound that we had has been resolved and has been gone for some time now. It was an issue with one of the injectors not getting calibrated properly at the shop. Injectors are all good now. New squash gaskets put in with now-cleaned and calibrated injectors. New lift pump. New primary & secondary filters (again). Pressurized the system to the Racor. No leaks. Ran the engine no problem from a bucket through the Racor. Figured it must be an issue of air getting in between the Racor and the tank. Suspected shut off valve as issue or blockage in pick up tube. Blew through pick up tube- no blockage. Took a sample of fuel from the tank- it is spotless. Replaced ALL fuels system hoses (except return line). Ran engine without diesel fill cap on in case vent was blocked somehow. Removed the pickup tube and pressurized it to check for leaks. None found. So, we are at a loss as to why the engine only runs for 20 minutes, then hesitates and stalls. It starts up just fine every time. Runs well, then around 20 minutes, starts to hesitate and finally a beep and then she dies. If pickup tube is fine, tank vent is fine, all new fuel line hoses, injectors cleaned and reinstalled, new lift pump, Racor not leaking and new filters installed, all fittings in fuel system checked and are tight what the heck could be causing the engine to die after 20 mins every single time? Ack! We are thinking next step is to put an electric pump on and pressurize the whole system.

Impavidus · « **Reply #15 on:** March 21 2018, 17:49 »

Craig. Does the engine re start straight away after it stalls?

Ant.

sailprincess · « **Reply #16 on:** March 21 2018, 17:53 »

This is SailPrincess (not Craig). Yes, it does start up every time no problem after it stalls...

IslandAlchemy · « **Reply #17 on:** March 23 2018, 08:24 »

Not a dry joint in a relay possibly? Or a dodgy stop solenoid? Just thinking that if it stops after 20 mins, something might be failing as it gets hot (dry joint).

I does sound like a fuel problem, but you seem to have covered all the bases.

sailprincess · « **Reply #18 on:** March 23 2018, 18:46 »

Thanks... ya, we really are stumped. Can't seem to figure it out as it really seems like air. The beep isn't a solonoid or anything. It is because the rpm's drop way down and the beep is the start battery saying it doesn't have enough juice. We are going to use an electric pump and pressurize the entire fuel system to see if we can find a leak somewhere. Any other suggestions are welcome!!!

MarkTheBike · « **Reply #19 on:** March 24 2018, 11:20 »

OK, this may be really a daft suggestion but how about the decompressor mechanicals (+ heat)? To be fair, I don't know much about how that bit works but it sounds to me like you've tried everything else and that's the only bit left unchecked. And its primary purpose is to stop the engine...

sailprincess · « **Reply #20 on:** March 24 2018, 16:10 »

No suggestions are daft at this point! What is a 'decompressor mechanical' though?

MarkTheBike · « **Reply #21 on:** March 27 2018, 13:28 »

Oh sorry - my MD2030 has a T-handle on the stbd side of the binnacle that you pull to stop the engine. The handle pulls a cable that runs down to a lever (on the left when looking at the fanbelt), which performs some magic (that's the bit I don't know) and the engine stops. I have no idea if it's even possible for this to fail but you guys really seem to have tried everything else. I'm sure one of the techies would be able to expand or dismiss. I called it a 'decompressor' because that's how old diesels used to be stopped, this may just close a valve in the fuel flow.

Symphony · « **Reply #22 on:** March 27 2018, 17:29 »

Quote from: MarkTheBike on March 27 2018, 13:28

Oh sorry - my MD2030 has a T-handle on the stbd side of the binnacle that you pull to stop the engine. The handle pulls a cable that runs down to a lever (on the left when looking at the fanbelt), which performs some magic (that's the bit I don't know) and the engine stops. I have no idea if it's even possible for this to fail but you guys really seem to have tried everything else. I'm sure one of the techies would be able to expand or dismiss. I called it a 'decompressor' because that's how old diesels used to be stopped, this may just close a valve in the fuel flow.

It stops the engine by cutting off the fuel. On later boats it is operated electrically by a solenoid. A decompressor is a different thing and works by lifting one of the valves mechanically so there is no compression in that cylinder. Not been used for stopping engines for many years and even then not usually by a remote cable. more useful when starting an engine particularly by hand as those of us who used old aircooled Listers know! Crank it up with the decompressors up then drop one and hope it fires before it kicks back and breaks your arm!

MarkTheBike · « **Reply #23 on:** March 27 2018, 22:34 »

Cheers, Symphony. So it's probably not the shutoff causing Sail Princess's engine problem... oh well.

tckearney · « **Reply #24 on:** September 10 2018, 14:07 »

Hi all, I am thinking of having my fuel injectors serviced this winter. As far as I know they have never been done in over 15 years. The engine is a MD22 55hp four cylinder. A friend suggested I try to obtain a price for new before getting them serviced. Can anybody advise if these are supplied by any other suppliers than Volvo (for obvious reasons) At the end of the day these are probably made by Lucas or somebody similar and just supplied with the customary mark up as Volva Penta . I understand these engines are really Perkins anyway.