Engine knock after injector pump and injector rebuild

[IndyJay]

I have a 1994 MF1250 that I sent out for injection pump and injector rebuild. Came back 4 months and $2,800 later with a bad engine knock. I've had the tractor since it was new and had never heard it knocking. Any idea what it could be?

I know, 27 year old tractor, hours are unknown since tach hasn't worked for probably 20 years but looking for some things to check.

34HP Iseki TK532, 91.4ci/1.5L

Thanks!

 

[RickB]

Fuel injection timing.

 

[IndyJay]

Thanks Rick. Everything I hear points to injection but the dealer is insistent that the rebuilder has everything to spec. They pulled the head and oil pan, didn't see anything beyond what you would expect from a 27 year old tractor. Not sure how to proceed, they are saying that there will will be more charges for them to pull the pump and send it back. Is this something a dealer normally can do or is it best left to the rebuilders?

Thanks again, Jay

 

[RickB]

I'm saying it's HIGHLY probable the dealer installed the pump incorrectly; not timed correctly to the piston travel.
Not faulty injectors or an imperfect pump rebuild.
It didn't knock before they removed the pump and now it does. That's what I'm reading. Am I right?

Probably advanced more than it should be.

 

[Fixastuff]

I'd try bleeding the fuel lines at the injectors before worrying about anything worse.

 

[IndyJay]

Rick, you are exactly right. Thanks for clarifying the specific likely cause.

 

[Unclewillie]

I'd try bleeding the fuel lines at the injectors before worrying about anything worse.

yep this is what I was going to suggest because my tractor has knocked like he's stating twice once when it got water in the fuel and another time when I replaced the fuel filter and apparently got air in the line.

 

[Unclewillie]

I have a 1994 MF1250 that I sent out for injection pump and injector rebuild. Came back 4 months and $2,800 later with a bad engine knock. I've had the tractor since it was new and had never heard it knocking. Any idea what it could be?

I know, 27 year old tractor, hours are unknown since tach hasn't worked for probably 20 years but looking for some things to check.

34HP Iseki TK532, 91.4ci/1.5L

Thanks!

Time to bleed some fuel lines and make very sure the fuel is clean .

 

[IndyJay]

Time to bleed some fuel lines and make very sure the fuel is clean .

They did drain entire fuel system, new filters and fuel just as good practice.
Would assume that professional mechanics would know to bleed but I will certainly suggest that.

Much thanks to all who have replied. Should be an interesting conversation come Monday.
Hopefully it is one of these and I haven't thrown almost $3k out the window!

 

[LouNY]

One other possibility is a crossed set of injector lines.