new head gaskets, now runs rough and smokes

IdahoMike

Member
Jul 12, 2020
52
5
8
I replaced the Bent connecting rod, the piston, all the rod bearings, and rod bolts. Reused the rings that were on the original piston as the end gap was still on the low side of the book tolerance. That was at about 163k.
I thought you were talking about push rods not connectors, thats major surgery, have to pull the engine for that one...
 

IdahoMike

Member
Jul 12, 2020
52
5
8
Well, I got it all together, fired it up and it threw a code which it did not do before, P0208, injector #8. I already pulled twice and cleaned it. any secret agent way to test the wires going to it?
I cleared the code and started it but this time no code still running rough, definitely one cylinder is not firing. I tried to attach a video but it will not let me for what ever reason..
 
Last edited:

jlawles2

Well-known member
Jan 28, 2010
1,058
39
48
Danbury, TX
I was referring to the push rods. If you set the lash to tight at the bottom of the lobe stroke (basically partially opening the valve) then at top of lobe stroke, the spring goes into coil bind which leads to failure of a push rod.

My connecting rod issue was hydro lock due to stupidity. I do not know how much too short it was, but it was just enough that the piston became friends with the crank.
 

IdahoMike

Member
Jul 12, 2020
52
5
8
How could you be "180 out" if you did not change the cam chain??? pulling the heads has nothing to do with timing
Thanks Mogman, you are correct. My thinking was if I was on #4 TDC and made the adjustment at the #1 cylinder thinking it was on the #1 but I was not, I guess that would be 360.
 

IdahoMike

Member
Jul 12, 2020
52
5
8
If you can get a video that might help us figure it out. Where about in Idaho are you? I am in the Treasure Valley and might be able to come look in person with my scan tools if you are in that general area.

I tend to agree that it is unlikely an injector went out, unless they were damaged/contaminated during the work. If you were careful and clean, that is probably not the problem. Having the valve lash way off could do what you are seeing.
I took a video yesterday but having problems attaching it to this thread...:(
 

IdahoMike

Member
Jul 12, 2020
52
5
8
If you can get a video that might help us figure it out. Where about in Idaho are you? I am in the Treasure Valley and might be able to come look in person with my scan tools if you are in that general area.

I tend to agree that it is unlikely an injector went out, unless they were damaged/contaminated during the work. If you were careful and clean, that is probably not the problem. Having the valve lash way off could do what you are seeing.
Mornin Dave, what are the chances of you swinging by sunday, I'm out of town today and tomorrow?
 

DAVe3283

Heavy & Slow
Sep 3, 2009
3,727
296
83
Boise, ID, USA
Update on this: Mike had disassembled the injectors to clean them. Disabling injectors #1 and #3 (also tested by unplugging #3) would cause a loud knock.

Balance rates were all -4 except #4 and #8 which were +12.

Mike found a shim sitting on the workbench, so he pulled the injectors back apart and found #2 was missing the shim, causing the injector to leak fuel constantly. Put that back and it runs fine.

Never done much with the LBZ, but I find it strange that disabling #1 & #3 caused a knock, the bad balance rates were on #4 & #8, but the actual problem was #2. In my experience with LB7s things track a bit more consistently. That said, having an injector leaking that much fuel was probably throwing the ECU (and us) for a loop.
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,611
1,868
113
Mid Michigan
Where's that "doh" smiley when I need it? Oh well, at least he got help from someone who knows what they're doing. :)
 

IdahoMike

Member
Jul 12, 2020
52
5
8
Update on this: Mike had disassembled the injectors to clean them. Disabling injectors #1 and #3 (also tested by unplugging #3) would cause a loud knock.

Balance rates were all -4 except #4 and #8 which were +12.

Mike found a shim sitting on the workbench, so he pulled the injectors back apart and found #2 was missing the shim, causing the injector to leak fuel constantly. Put that back and it runs fine.

Never done much with the LBZ, but I find it strange that disabling #1 & #3 caused a knock, the bad balance rates were on #4 & #8, but the actual problem was #2. In my experience with LB7s things track a bit more consistently. That said, having an injector leaking that much fuel was probably throwing the ECU (and us) for a loop.
Dave, I cannot thank you enough for taking time out of your day to help out a stranger. Without your help It would have taken me longer to pinpoint the problem.
I also want thank all of you that extended what knowledge you have in helping out with the process of elimination.
So, lesson learned, I took apart the injector tip to spray test each of them and clean them up, I did not see the shim that rolled out which looks like a little 1/4" washer 1/8" thick actually 1.33 mm depending on the shim as they are all different, this shim goes into the injector body first then the spring then the small barrel tube that fits over that, now there also is a tiny little puck type shim that fits on top of the injector needle, it is tiny maybe 1/6" diameter you loose it good luck finding it. I ended up taking out each injector and checking for the shim, of course it was the very last one I checked.
All of this and 900 bux later, but to me was well worth it as I learned a lot about my motor. All because of a coolant leak from behind the motor, which by the way is still leaking. That will be another chapter.
 

LBZ

Super Moderator
Staff member
Jul 2, 2007
9,903
149
63
46
B.C.
Update on this: Mike had disassembled the injectors to clean them. Disabling injectors #1 and #3 (also tested by unplugging #3) would cause a loud knock.

Balance rates were all -4 except #4 and #8 which were +12.

Mike found a shim sitting on the workbench, so he pulled the injectors back apart and found #2 was missing the shim, causing the injector to leak fuel constantly. Put that back and it runs fine.

Never done much with the LBZ, but I find it strange that disabling #1 & #3 caused a knock, the bad balance rates were on #4 & #8, but the actual problem was #2. In my experience with LB7s things track a bit more consistently. That said, having an injector leaking that much fuel was probably throwing the ECU (and us) for a loop.
Possibly due to the firing order is why 1&3 made it knock. 3 and then 1 come before 2 so that would be 3 holes that never fired before 7 then 8 & 4.

Good find though.
 
  • Like
Reactions: dndj

IdahoMike

Member
Jul 12, 2020
52
5
8
Well, I figured I had everything back to normal till I started driving and noticed the black smoke pouring out when I take off from a stop, the more I accelerate the more it blows. The air cleaner is fairly new, I cleaned all the injectors and put them back together with no left over parts and in proper order with shims and springs. Any ideas or things to check??
 

2004LB7

Well-known member
Dec 15, 2010
6,982
2,145
113
Norcal
did you forget a rag in the intake?

there is a lot of reasons for black smoke. it really means not enough air for the fuel. you might need to run some logs of airflow, boost, mm3, fuel pressure, etc to see what's on.

it could also mean mechanical issues such as one or more leaking injectors. leaking EGR, turbo vanes, etc

it might be a good idea to return the tuning to stock until you get all of the issues resolved so we can rule out tuning being the reason
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,611
1,868
113
Mid Michigan
I think you screwed up your injectors when you tore them apart.

IIRC, "Injectors Direct" was one of the places that had a very poor reputation for injector quality in the first place.
 
  • Like
Reactions: 08lmm72mm

IdahoMike

Member
Jul 12, 2020
52
5
8
did you forget a rag in the intake?

there is a lot of reasons for black smoke. it really means not enough air for the fuel. you might need to run some logs of airflow, boost, mm3, fuel pressure, etc to see what's on.

it could also mean mechanical issues such as one or more leaking injectors. leaking EGR, turbo vanes, etc

it might be a good idea to return the tuning to stock until you get all of the issues resolved so we can rule out tuning being the reason
HA, HA, no rags... I'm thinking a boost issue, gonna check all the fittings and gaskets
 

2004LB7

Well-known member
Dec 15, 2010
6,982
2,145
113
Norcal
I think you screwed up your injectors when you tore them apart.

IIRC, "Injectors Direct" was one of the places that had a very poor reputation for injector quality in the first place.
I'd probably put money on this one too. if I recall correctly wasn't injectors direct the same as the pensacola company that has ruined more injectors then Bosch in the LB7 has? something just doesn't sit well with me on this
 

IdahoMike

Member
Jul 12, 2020
52
5
8
So, I did some google researching and found that I may have a boost issue. Popped the hood and started checking all my clamps that had to do with air, low and behold the hard plastic fitting on the hot side (pasngr side) below the airbox was not fit properly so I refit the coupling with the funky ring that holds it together, I'm now in business again, runs like it did before, perfect, But I still have the coolant coming from the bellhousing at the bottom, a constant drip. I guess there are 2 plugs on the back side of the block that could be leaking, that sux, I'd have to drop the tranny to get to them unless there may be something else just can't see behind there from up above and with a camera probe can't see well enough.... arg...