Injector knock, but no smoke?

[Sycostang67]

My truck has been knocking for the last 5k miles since I replaced my injectors. The truck runs great, I dont have any extra smoke, and none of my lines feel hot. Could it still be an injector causing the knock? If you stand in front of the truck you can barely hear the knock, but on either side of the truck the sound is quite prevalent. It's really getting on my nerves as it echoes off other vehicles in traffic and drive-thrus make me want to put a spork in each ear. I tried retarding the timing a hair but that caused constant smoke at idle.

 

[icanfixall]

Crack each injector line loose one at a time till you find the bad one. I'm thinking you didn't buy from a reptual shop or had them pop tested before you installed them. Where did you buy these injectors from....

 

[Agnem]

X2 on what Gary said. Sounds like a leaker.

 

[Dsl_Dog_Treat]

X3 on a leaker.

 

[Diesel JD]

I thought they were Typ4's? If so I'm sure he would make it right by you providing you can isolate it. Hopefully it's just an injector and not a valve. Another possibility that you need to consider is an exhaust leak over there which can cause noises like that, and also make sure you don't have any injectors that might be loose in their bore.

 

[Sycostang67]

I did get them from russ(typ4). I thought if one was leaking though I would get a lot of smoke at idle. The timing was set to 0* as well. I guess I will crack them all when I get a chance this week. No exhaust leaks, I buttoned all that up a few months ago.

 

[HankHill]

my truck also has an injector knocking, same symptoms as you sysco, does it hurt anything to keep driving it the way it is? I've put about 3200 miles on my truck while this has been going on

 

[Black dawg]

can be real tuff to find the noise cracking lines. just pull them and test them.

 

[Diesel JD]

Probably the only thing it'll hurt is your wallet since our IDIs have the precup so it isn't squirting down on the piston directly, but it all depends on how bad it is, if it's sticking open you could even lock up the engine.

 

[HankHill]

Probably the only thing it'll hurt is your wallet since our IDIs have the precup so it isn't squirting down on the piston directly, but it all depends on how bad it is, if it's sticking open you could even lock up the engine.

yikes, I will try this injector loosing today, so basically what happens is by loosening the injector nut it sprays out rather than into the injector, cutting that injector off from firing? which then you might here a difference in sound because its not hanging open

 

[Sycostang67]

I hope it doesn't hurt anything. I have about 5k miles with mine doing it. I thought it was normal at first, especially after having the timing set since people said that would cause it to knock a bit, similar to a psd. My truck sure doesn't sound like any psd i've ever heard. Hopfully I can locate the offending injector by cracking the lines, I could use one of my old injectors to keep the truck running if I have to while I sort the bad one out with russ.

 

[Brianedwardss]

It's a bit time consuming on a turbo truck, but I had this same issue a few months ago. After cracking open the lines didn't get me any results, I took on old injector and swapped it one by one til I found the leaker. One by one I would swap 'em and fire up the truck. Mine was the back driver side one. But being N/A and no A/C currently installed it was a piece of cake to do this.

 

[phazertwo]

I have the same issue, let us know what you find!

PZ

 

[Agnem]

Anybody can sell an injector that goes bad. Despite all the effort to control quality, there really is no way to fully test an injector under all the conditions that will be encountered in a cylinder. A pop tester doesn't allow you to put combustion presure against the pintle, nor the heat that will be encountered. Injectors are built to spec, and from there you have to just cross your fingers that it's going to hold up. Just be glad it went bad early when some warranty can be had, rather than later when its out of warranty.

 

[Dsl_Dog_Treat]

Anybody can sell an injector that goes bad. Despite all the effort to control quality, there really is no way to fully test an injector under all the conditions that will be encountered in a cylinder. A pop tester doesn't allow you to put combustion presure against the pintle, nor the heat that will be encountered. Injectors are built to spec, and from there you have to just cross your fingers that it's going to hold up. Just be glad it went bad early when some warranty can be had, rather than later when its out of warranty.

Seen em first hand bad out of the box.