03 Sierra Prostreet Paperweight
01-08-2017, 11:38 AM
#11
Well... took it for a mile drive, and now I am seeing extreme misfires like it was before. I am talking counts over 100. Pretty much dead cylinders. I can post logs and tune if anyone is interested in seeing. Pre-drive, ran great in driveway. Post-drive, barely wants to idle in garage. Was a simple cruise around my block and back. This is very similar to the issue the truck had prior to the complete fuel system revamp. Only doesnt explain why it ran great up until I drove it...
01-08-2017, 05:38 PM
#15
The "new FP" log is pre drive once I dialed in FP to 58psi. The other 2 logs are after the drive now that it has misfiring everywhere.
Tune (E-fans and Evap removal, all else should be stock).
I havent pulled the plugs yet today, but I changed them back in May (the truck has been sitting since May, just got transported to TX 2 weeks ago).
I plan to pull a few plugs and check them out. Stock injectors looked clean when I put the rails on. I have 60# injectors waiting for the turbo install, I just havent installed them because I didnt get the injector tables with them like some of the better vendors send with them. They are Siemens Deka 60#, and require the harness adapters.
Thoughts?
Tune (E-fans and Evap removal, all else should be stock).
I havent pulled the plugs yet today, but I changed them back in May (the truck has been sitting since May, just got transported to TX 2 weeks ago).
I plan to pull a few plugs and check them out. Stock injectors looked clean when I put the rails on. I have 60# injectors waiting for the turbo install, I just havent installed them because I didnt get the injector tables with them like some of the better vendors send with them. They are Siemens Deka 60#, and require the harness adapters.
Thoughts?
01-13-2017, 05:47 PM
#16
Couple quick notes:
Cylinder 7 is the only cylinder that hasnt misfired through all of this. Cly 2 is a close second with only a couple. All other cylinders are basically misfiring at will.
Noticed my ignition voltage was lower on my scan today, like dipping into the 12's. An hour after shutting the engine down, the Alt was still hot as hell. An hour after that, still hot. So the alt is coming out for an HO. Now that I have e-fans, probably better to upgrade it anyways.
All that being said, the alt going out will not fix the misfiring issues. Pulled a couple plugs, just had a fuel smell and slightly wet, what I expected. No other signs of anything. Still at square 1. Going to pull the new fuel filters tomorrow if I have time to check them out.
Cylinder 7 is the only cylinder that hasnt misfired through all of this. Cly 2 is a close second with only a couple. All other cylinders are basically misfiring at will.
Noticed my ignition voltage was lower on my scan today, like dipping into the 12's. An hour after shutting the engine down, the Alt was still hot as hell. An hour after that, still hot. So the alt is coming out for an HO. Now that I have e-fans, probably better to upgrade it anyways.
All that being said, the alt going out will not fix the misfiring issues. Pulled a couple plugs, just had a fuel smell and slightly wet, what I expected. No other signs of anything. Still at square 1. Going to pull the new fuel filters tomorrow if I have time to check them out.
01-20-2017, 03:33 PM
#17
Decided to order an LM7 takeout from LKQ for the truck. Figured I can install everything on the stand, mount it to 80e, and drop it all in at once. Might need to buy new headstuds, since the ones I purchase were 3 length.
I did install the new Alt, still having misfires as expected. Far less than the 1st log posted, but steady misfires. I am going to add a 4ga ground to the block and triple check the frame ground as well for cheap assurance. Still trying to find the issue with 4.8 because Im keeping it to build for another project that I have down the road. Ordered a spark checker as well, as i lost my old one when moving.
I did install the new Alt, still having misfires as expected. Far less than the 1st log posted, but steady misfires. I am going to add a 4ga ground to the block and triple check the frame ground as well for cheap assurance. Still trying to find the issue with 4.8 because Im keeping it to build for another project that I have down the road. Ordered a spark checker as well, as i lost my old one when moving.
Last edited by xxch0dyxx; 01-20-2017 at 03:39 PM.
01-21-2017, 08:54 AM
#19
130k on the clock, they had pics of the donor vehicle as well. 6mo or 6k warranty, whichever comes first. The 6.0's are ridiculous the prices they want for anything under 200k... 1500 is the lowest I could find. Ill wait until I buy a built block over spending that for JY grab.
Was 600 picked up, no core charge. Going to have a buddy grab it for me Monday. Triple Edge Performance is going to replace all the gaskets, check bearings, cam, studs, and possibly throw some ported 317s on. Then freight it to me with my 4L80e/TC so I can drop it all in at the same time.
In the mean time, I am still chasing the 4.8 ghost. Checked/added another 4ga ground last night, didnt help. Ordered a crank sensor to try as well.
Was 600 picked up, no core charge. Going to have a buddy grab it for me Monday. Triple Edge Performance is going to replace all the gaskets, check bearings, cam, studs, and possibly throw some ported 317s on. Then freight it to me with my 4L80e/TC so I can drop it all in at the same time.
In the mean time, I am still chasing the 4.8 ghost. Checked/added another 4ga ground last night, didnt help. Ordered a crank sensor to try as well.
