Diesel Place banner

1 - 10 of 10 Posts

·
Registered
Joined
·
4,805 Posts
Discussion Starter #1
I just installed new marine injectors. At first startup, it whistles. Not turbo whine, but it whistles. I was going to take it for a test drive, but I didn't make it out of the driveway before it started knocking HARD. I had the turbo off. I put everything back the way I found it. No parts left over. None missing either.

What should I check first?

Everything was going so well. Then I try to do some preventative maintanence. This makes me want to -:t
 

·
Registered
Joined
·
58 Posts
Did you make sure that all the air is out of the lines? Another thing to try is to isolate the knock, and see if it moves when you swap injectors arround. IE, if its knocking at #7, swap that injector with another and see if the knock moves with it.
 

·
Registered
Joined
·
7,434 Posts
Bad injector probably. Might clear out if you drive it down the street.

You wouldn't want my opinion of "marine " injectors.
 

·
Registered
Joined
·
6,945 Posts
The marine hi-pop hi-flo injectors make considerable noise at idle, even more at low idle, which occurs because PCM does not - cannot - manage idle speed well with those injectors.

Knocking while headed down the street may well, as DP stated, just require driving to clear up, but you can substitute the injector(s) into different positions to verify weak unit.
 

·
Registered
Joined
·
4,805 Posts
Discussion Starter #5
took it for a ride. it cleared right up.

Idle is smooth and I don't notice a significant if any increase in engine noise. Throttle response is smoother. I'm happy with them so far.

That knock scared the hell out of me. I really thought something was broken. Must have just been air. Sorry for the false alarm and thanks for the replies.

-Joi
 

·
Registered
Joined
·
1,259 Posts
I would not think air would make a knock (could be wrong) I'd think that an injector was stuck open, causing fuel to dump and giving a Knock symptom...My 2 cents
 

·
Registered
Joined
·
889 Posts
I have read a few posts that some new injector installs require some run time to get out all air and they can make noises before expelling all the air.

One thread mentioned replacing one bank of injectors at a time. Cranking engine in between to clear air.

I think its the air in the lines/injector make the timing really off on that cylinder and you get odd combustion and hence the knock.
 

·
Registered
Joined
·
7,434 Posts
Raw fuel what causes knock. Injector is stuck open. From dirt in injector during install or gummed up injector from sitting on the shelf to long.

Well did you get 40 more horse power?
 

·
Registered
Joined
·
4,805 Posts
Discussion Starter #9

·
Registered
Joined
·
158 Posts
1 - 10 of 10 Posts
Top