03 Silverado 1500hd 6.0 Mods Won't Now barely idles

[oldnoob]

Hey everyone, I'm new to the forum and really to modifying vehicles. I've always done all my own repairs without issues, but the last 2 weekends has me really stumped so I figured I'd hop on and ask the gurus to see if I'm even on the right track.

The vehicle is a 2003 1500HD 6.0 LQ4 with return style fuel system. With the original intent of just changing the cam I ended up doing a bunch more. Here is everything I just did.

BTR Truck Norris cam. New valve seals and springs.
TBSS Intake with the 90mm TB-Gold blade using the Xlink 50lb injectors from Glenns
1-3/4 Long tube headers full 3" to x pipe and 2 mufflers
QFS 340LPH fuel pump
C5 58psi reg/filter

Initially I had the C5 reg/filter mounted next to the rail, but had concerns as any slight side load would cause it to leak on the output side. All I did to the stock tune was modify the Flow Rate vs KPA from 25 to 50lb injector, and it seemed to idle correctly with a little idle lope.

Last weekend I moved the C5 reg/filter down to where the stock fuel filter was close to the tank. In doing this I switch to a 6AN version of the C5 reg. When I went to start it I noticed it didn't nearly as smooth at idle. I noticed the B2 O2 was .450mV constant so I changed out the O2 and now it is behaving like B1.

Is it possible that locating it to the rear would cause the rail pressure to be that much lower? It's all 3/8 from the filter forward. I checked all the plugs and they were all darker brown, but on one side it was white like it was washed clean? I checked and made sure all the gaps were 0.045".

I don't have my wideband installed yet. Now that it is relocated I'm getting P0300 periodically and noticed that knock is occuring.

If anyone could give me a suggestion it would be much appreciated. The second one all I did different was change from 50lb/hr to 45lb/hr hoping to trick it to add more fuel.Stock20031500HD-45lbhr.hpt

24-04-27 16-58-46.hpllatest.hpl

[ns158sl]

Looks like an exhaust leak on bank 1.

What is

50lb injectors from Glenns

[oldnoob]

Sorry it was a package that included the tbss intake manifold with the fuel rails and
GM/Delphi 50lb/hr at 58 psi Injectors (Part number 12613412).

https://www.glennsautoperformance.co...ails-injectors

I did heard a ticking noise on the drivers side only. I couldn't tell if it was internal or an exhaust leak. I'll check that in the morning.

[gtstorey]

Typically “return” style fuel system means vacuum regulated and c5 means constant pressure. Which are you trying to do?

[oldnoob]

Typically “return” style fuel system means vacuum regulated and c5 means constant pressure. Which are you trying to do?

I'm just trying to run the constant 58psi. I was just trying to describe the system since the 03 Silverado was a change over year where some had a 3/8 supply and 5/16 return line, and some only had the 3/8 supply midyear and all 04+. Since mine had the return I had to use the C5 regulator/filter

[TheMechanic]

If it is a 412 GM injector then your data is wrong.
Here is a non referenced to your data.
You have a bit of tuning to do. You may want to start over with the correct injector data.
Stock20031500HD-50lb_412.hpt

[oldnoob]

I spent a bunch of time and found my exhaust leaks (about 1/4" section of butt joint that I missed welding, and the gasket was also leaking). I got a smoke machine to be sure and kept at it until I didn't see any more leaks.

I reverted to the stock tune with the injector data TheMechanic provided. B1 LTFT still goes up, so I'm not sure what I'm missing. I also swapped B1 and B2 o2 sensors just for a sanity check.

Here is my latest log. Any advice on what I should try next?

aftermanifoldleakfixedgasket.hpl2003HD 412inj.hpt

[ns158sl]

After driving it around the trims look like they are working. Right after startup there is something weird going on. It is triggering the knock sensors and driving the trims up. Can you hear it misfiring?

[oldnoob]

Yes at idle it sounds like it is misfiring pretty bad anything above that seems to be better. I've only drove it around my lot a little. Tomorrow I'm hooking the smoke machine up to the intake tract and looking for other issues. I picked up a fuel injection system diagnostics set and am going to look at the fuel pressure actually being seen at the rail. I swear it idled correctly when I had the fuel pressure regulator up by the intake. When I relocated it down to the frame rail I had to install new hose. Is it possible that debris from the cutting of the nylon hose could have caused an injector to clog and look similar?

I will verify the fuel pressure tomorrow, and look for any intake tract leaks. I would have thought if it was an intake leak or fuel pressure that both banks would have had the ltft issues. I'm just a newbie trying to make sense of it all.

Thanks again, I appreciate all the help

[ns158sl]

Id try to figure out what hole is missing. Temp gun at the manifold/header, kill a cylinder with VCM controls, or unplug a coil or injector one at time.