Fuel Injection Pump Problem

[aleggert52]

Hello Cruiser Forum,
I am currently in El Salvador. I have a Bayfield 32 Cutter with a Yanmar 2QM15 Auxiliary engine. I am currently experiencing a problem with the injector pump. The Problem: The engine will start fast and idle but when the throttle is advanced it will gain little RPM and lope and quit. I removed the injection pump and have had it to the lab for testing 4 times now with the same result. The fuel is new and clean as well as the filters and all air is removed from the fuel system. What I need to know at this point is: With the pump installed and the high pressure lines dis-connected at the pump and the throttle set at full how much fuel should I expect to see coming out of the injection pump? I would really appreciate it if someone knows and can answer my question. Thank you
aleggert52

[aleggert52]

The Problem: The engine starts fast and idles but when the throttle is advanced the RPMs gain little and the engine lopes and quits. I have had the pump to the lab 4 times with the same result. Question: the fuel is new and clean the filters are new all the air is removed from the fuel system. With the pump installed and the high pressure lines removed at the pump with the throttle full when I turn over the engine how much fuel should I expect to see coming out of the injection pump? Thank you

[MBWhite]

Not much, it will look like a tiny squirt from a squirt gun, maybe an eyedropper drop in size roughly and smaller than that if you look at it closely.



Have you removed the injectors yet? I am just giving out options here that may or may not be valid as I haven't seen this engine personally. However, after testing in a reputable shop (what would also be an option is see if there is anyone in your locale with this engine and swap pumps with them) is to consider the problem does not lie with the pump but elsewhere. A consideration is if you have a head gasket or valve (usually intake) leaking.



If you have an IR thermometer gun I'd run it at a speed where the engine just starts to burble and see if the temps of both cylinders go down or the temp of just one goes down.



Lastly, if you advance the throttle quickly to max do the RPM's go up first then die down or does it just fall on its face with no uptick in engine speed?

[Compass790]

I've never tried it with no injector line at the pump but you get a decent say 2ft high squirt out of an injector line disconnected from the injector.
Is the fuel rack moving freely?

[skipperpete]

Well it could be low fuel pressure from the lift pump, have you tried using a can of fuel on deck connected to the input of the secondary filter. Doing this removes a number of potential problem areas from the troubleshooting plan.
If the problem persists then it might be the governor settings or spring. There is a vague possibility that too much camshaft end float (loose retaining screws?) is messing with the governor, the flyweight assembly is on the camshaft end and the thrustplate and spring are on/in the timing cover so excess endfloat is a maybe?
Did this problem develop suddenly?
There should be about a 4mm high spurt? of fuel from the delivery valve holder when rotating the engine manually.

[skipperpete]

It seems that this thread appears twice on the forum....not sure how that even happens.

[Wotname]

Originally Posted by skipperpete

It seems that this thread appears twice on the forum....not sure how that even happens.

In this case because the OP raised two seperate threads on the subject. You will note that to date he has only made two posts to CF, this one and the other one you mentioned.

Nevertheless aleggert52, welcome aboard CF and hope you get the engine problem sorted soon. I reckon you are in good hands with Skipperpete (and others).

[aleggert52]

Hello MB White,
Thank you for your information on the how much fuel comes out of the injection pump. I have serviced the injectors but after the problem occurred. I have an electric fuel pump and the fuel line to the injection pump has plenty of volume but I do not get any type of squirt from the injection pump when turning the engine over even with the decompression valve engaged. I don't have an IR thermometer. There is no 2QM15 engine to swap the pump with. The RPM just falls flat on its face when the throttle is advanced quickly. This problem did occur suddenly. from one starting to another. It has really got me stumped!

[aleggert52]

Hello Skipperpete,
Thank you for your reply. I have an electric fuel pump and the line going to the injection pump has plenty of volume. This problem did occur suddenly. prior to it the engine performed just fine. there is no spurt from the injection pump at all when the engine is turning over even with the decompression valve engaged. Shouldn't the lab be able to detect fuel flow when the test the pump?

[aleggert52]

hello Wotname,
Thank you for your reply. I am new to writing in this forum please forgive me if I stumble a bit. I did post 2 threads mistakenly thinking I only posted one.

[MARC D]

When your engine runs at idle, would you say it has normal sounds and not shaking excessively?
Do you see any blowback oil?

[aleggert52]

Hello Marc D,
Thank you for your reply. when the engine is running at an idle it seems to perform alright and is not shaking. I do not detect any blowback oil.

[MARC D]

How many hours on your engine?

[aleggert52]

Hello Marc D,
Thank you for your reply,
The 2QM15 engine has 1,700 hours, not to many.

[Compass790]

A pump testing machine does measure volume & pressure.
Strange a low hour engine has this problem but as skipperpete suggests governor linkages could be a problem.
Do you have a good filtration setup?

Disclaimer : I'm not a diesel tech but I did rebuild our ysm8 injection pump which is basically 1/2 of a 2qm15 one.
Good luck with finding the problem & welcome to the forum