04 zf6 fuel knock

[mamumtsllc]

Hey guys. Got a 04.5 lly 3500 with the zf6 manual trans. Came in for fuel knock/miss and excessive black smoke. So ran cylinder cut out and found #6 had the knock. Kill the cylinder it goes away. Balance rate was a +8. Every other cylinder was +/- 3-4. So figured there's the problem. Changed #6 injector, cranked it up and exactly the same. So I thought maybe #5 which is directly across. So we put #6 injector in #5 hole. No change. Pulled ficm off good running truck. No change. Put #5 injector in #3 since that's the next cylinder in firing order thinking maybe??? No change.

So I'm back to the forums where you can actually get real help. No blow by. But im lost. Looking for ideas or any other wild ghosts to chase. Thanks


Sent from my SM-G991U using Tapatalk

 

[2004LB7]

Are you using the Tech 2 or another tool? Some others can read the injector numbers wrong. EfiLive has been known for this issue.

Some speculate that the number is actually the firing number and not cylinder number. So #6 firing would be #5 cylinder

 

[mamumtsllc]

Are you using the Tech 2 or another tool? Some others can read the injector numbers wrong. EfiLive has been known for this issue.

Some speculate that the number is actually the firing number and not cylinder number. So #6 firing would be #5 cylinder

View attachment 116358

Using a snap on Solus scan tool. I believe it actually kills the cylinder number that you select from my experience. But I will definitely pay closer attention to that tomorrow. Sounds like it's coming from the driver side.

Sent from my SM-G991U using Tapatalk

 

[Chevy1925]

On a customers vehicle, you should be running a compression test next. You assume injector when it could very well be something else. Also you never posted main injection rate for the balance rates. Without it, you only have half the story.

 

[mamumtsllc]

On a customers vehicle, you should be running a compression test next. You assume injector when it could very well be something else. Also you never posted main injection rate for the balance rates. Without it, you only have half the story.

Compression test is next in line. But let me just throw this out there to make sure I'm not missing anything. No blow by. Zero. So that tells me the cylinder walls and rings are still intact rite? No noise in intake or exhaust to give me a feeling that it has a bent, burnt or broke valve. I'm more than willing to run the test but I feel that I'm not going to find a low cylinder. Am I missing something else?

Sent from my SM-G991U using Tapatalk

 

[mamumtsllc]

Bringing this back up from the dead. Looks like o own the truck now. I ran compression test before and want to say it was in the 350 psi range but I cannot gurantee that. So I plan to get it running to pull balance rates again and then Check compression. I've seen guys say check it hot vs cold. Which gives me the best reading? Or do both?

Thanks.

Sent from my SM-N986U1 using Tapatalk

 

[2004LB7]

I'd do both if you can. Spec is for hot

 

[mamumtsllc]

I got a new set of batteries for this rig last week. Plan to pull it bavk up to the shop. Thinking ahead could it have a broke crank? Causing the fuel knock and black smoke? Other than those it runs smooth and does my make any noises.

I'm going to probably do a little digging but then try to move it along. Wife and kids are wanting a pontoon. So that money would do me more good towards a boat.

Sent from my SM-N986U1 using Tapatalk

 

[clrussell]

Thoughts

Have you ice picked the connectors? Any injector circuit codes?

 

[mamumtsllc]

Thoughts

Have you ice picked the connectors? Any injector circuit codes?

No codes. Have not ice picked anything though.

Sent from my SM-N986U1 using Tapatalk

 

[mamumtsllc]

Bringing this back up. Just thinking tonight the batteries have always been dead when I worked on it. Could one of the batteries be shorted out cause a voltage issue either with ecm or ficm? Still no codes that I've come across. But just curious.

Thanks

Sent from my SM-N986U1 using Tapatalk

 

[2004LB7]

Definitely. Easiest test is to have them charged up then disconnect both over night and measure the voltage of each battery the next day. The shorted one will typically be around high 10s to low 11s while the good battery will be 12.5 to 12.8 volts