LBZ injector knock cold

lbz pwr

New member
Nov 23, 2011
1
0
0
Hi guys, so I have a 07 LBZ 145k miles. When I start it cold it has a loud injector knock on pass side, Balance rates are 0.2-2.1 except for #3 it's 4.8-5.2. The knock goes away after 3 minutes of idling and when it warms up its 0.4-1.2 any ideas why it's loud cold and perfect warmed up?
 

Brent@LDS

Vendor
Vendor/Sponsor
Aug 23, 2011
651
1
18
Wisconsin
Sounds like the injector is sticking while its cold and not being lubricated properly until the fuel warms up.
 

henery97

Member
Apr 4, 2011
206
0
16
Nebraska
Could possibly be a bad glow plug on that hole...I had a bad one that didn't set a code, but I had a dead miss on cold start, balance rate was at 15.0. Maybe check compression on that hole too. Could have a bent rod as well, not likely though. Worth checking though before you replace the injectors
 

bbolden516

New member
Jan 21, 2017
26
0
0
Derby Kansas
x2 on what henery97 said, injectors are pretty easy to move on these newer trucks you could move it to another easy to get to injector and see if the problem follows, also while you have the lines apart, if you go that route put some clean 2 stroke in there it will help with lube issues if that is the case, just my 2 cents worth. Good luck and let us know what fixes it.
 

Ridin'GMC

I like red
May 20, 2010
614
5
18
MA
Sounds like the injector is sticking while its cold and not being lubricated properly until the fuel warms up.

Mine does the same thing. None of the additives I tried works when it hits below 20 degrees. Considering at 177k miles, it's probably time to replace because of the sticking injectors and probably a bad pilot.