Engine knock

[markha1]

OK ... Good morning all..... is it morning ??? Cant tell been up all night thinking about this one . Here it is... I seem to have developed a knocking noise. Can't really hear it at idle, only accelerating and at road speeds. sounds like 1 Cly knocking. Like an old lawn mower will do sometimes. Also the engine will surge and falter VERY slightly and almost cant detect it. Boost pressures normal, oil pressures normal, No EGT data..... yet . OK where do I start to look ??? Valves, bearings, Oil was changed a few hundred miles ago, new oil,fuel filters. I have never adjusted the valve train, and am not real sure how to. After all this is my first TD

I am willing to do the work, just prefer some one who knows to be handy

Mark H

 

[rlyons]

Check your injector lines and ensure they are tight and not leaking, a loose injector line will cause a knock like a rod knocking.

 

[CDegner]

a bad injector will also do that. People where always telling me I had a rod knocking (keep in mind these people didn't have a diesel) before I changed my injectors out. New injectors got rid of that noise.



Carl



bTW, get those valves adjusted. Do a quick search on here and you will find several procedures spelled out for you. Just remember valve lash is adjusted on a cold engine. 0. 010" intake, 0. 020" exhaust.

 

[markha1]

Originally posted by rlyons

Check your injector lines and ensure they are tight and not leaking, a loose injector line will cause a knock like a rod knocking.

how is this done ??? I have been chasing what appears to be an oil leak arround #3&4 cyls,. Leaking injectoe ?!?!

 

[paccool]

Keep your fingers and hands away from that area if you think there may be a leak. There is high pressure that could cause some injury. Use a piece of paper or cardboard and hold around the area you think may be leaking. Do this with the engine running.



Sounds like Carl may have identified your problem. Especially with the engine running a little off and surging.

 

[markha1]

OK spent most of yesterday adjusting the valves. Got that done but no soap. still has that "knocking" noise, 400+K miles ... . Rod Knock????? or injectors???

Mark H

 

[nascar mark]

Carl is most likely right. Pull your inj's and either upgrade if you have more than 200k on them and don't look back or if they have life left in them, take the set to a Bosch inj shop and have them checked/set.



Most likely one of the inj's is dribbling and causing the knock.

 

[markha1]

they saw 200 k a while ago. 423K. Cant afford new inj's. Is it ok to drive for now ??

 

[phillips5]

A dripy injector could melt a piston. If you are going to drive it keep your foot out of it. I wish I lived closer I have a pop tester. I could set them. Have you cracked the nuts loose 1 at a time while runing to see if the knock goes away and what cylender it is. If you loosen 1 and it goes away tighten it comes back than that is the cylender.

 

[markha1]

no I have never heard of that test

TDr's are brand new to me

which nut ? the big one on the bottom ?

 

[Paychk]

Where the fuel line connects to each fuel injector there is a nut to hold it in place(at the top of the injector). If you crack open (slightly open) the nut, the fuel will vent to the atmospere and not inject to the cylinder. When this happens to a healthy injector/cylinder the idle will change, usually slow done. When this is done to a sick injector/cylinder the idle won't change, you have found the problem cylinder/injector.





Be very careful when cracking open the injectors, if the spray hits your skin it can cut you or drive the diesel under your skin!

 

[1stgen4evr]

Knock?

You have a PM.



1stgen4evr

James

 

[dpuckett]

Also, an injector tip that is clogged up a little will make a knocking sound. Run some cleaner through the tank (make sure it is for DIESELS, not gassers) at about 3x dose- wont hurt anything- and see if that helps.



Retarded timing will make a knock- BTDT. You already have the valves set so I'd cross that off the list.



EDIT- while going up Big Thompson Canyon (6% grade or so), i got a knock from the engine under light throttle. Long story short, 1100mi later, after half a gallon of injector cleaner (and possibly the altitude difference accounts for some of it), the knock is gone, and I'm left with just the throaty growl and roar.

Daniel

 

[R.E. Miller]

Not to shower on your parade, but if you really think that you have a rod knock, pull the oil filter and cut it open. If you really have a rod knock, and it is as noisy as you have described, you should find some bearing material. I still lean to the injector bit. I pulled mine out of my plow truck last year, and they were so far out of whack, I could not understand why it ran as good as it did.

Russell

 

[markha1]

The regular oil change is comeing up shortly, I will cut it open and see what's in there. I haven't tried the losening of the fuel supply line yet. It seems ro run real well, just has this dang noise " RAT RAT RAT" oh and it seems to be louder on hot days. ?

 

[phillips5]

Check your torq converter bolts make shure that they are tight. A rod knock is going to be a hard solid knock. One time my truck slid off the jack and landed on the pan. Made a dent and bang bang bang I had to pull the dent out. Are you stick or auto any way. Also if stick when the pressure plate straps let loose they go rat rat rat to.