I just recently replaced my injectors in my LB7 because of buying bad fuel. The fuel was full of Allgy and blew all 8 injectors. I replaced all of them. I noticed a Small slight knock. The next day the knock got worse as well as white smoke coming out my exhaust. The codes that pull up are 307. I also have blow by white smoke coming out my oil fill cap. Now I have a huge oil leak as well. Any ideas on what to do?

 

change fuel filter, check balance rates, desired and actual fuel pressure, compression check of each cylinder.

Code P0307 is misfire on cylinder #7. since you just replaced them all there is a possibility that one or more of the electrical connections on the injector is not tight or has come loose. this has happened to quite a few people who have just replaced injectors, digging back into it and finding loose wires on the injector studs.

i hate to say it but i think you need to take the upper valve covers off and inspect the connections. better than a headgasket if that is all it is.

 

Tore down left side of engine injectors looked like hell. The cup that injector 7 popped free the O rings wore out. How exactly do the heads work with the cups for the injectors?

 

The coolant that flows through the heads flows around the cups. The cups are pressed into the head and sealed with some special GM sealant, some say it is just green locktite, a copper crush washer is then put into the bottom of the cup and the injectors are then put in. All of the "O" rings need to be lubed to provent damage during installation.

If the cups come loose or are not sealed properly then coolant can get by and mix with the oil or go into the cylinder which seems to happen more often. Some times when removing the injectors while pulling up on them a cup can break free. Then you can get all sourts of problems after putting new ones in. Many as a point of insurance pull all of the cups too while doing an injector job and reseal them.

 

Good that's awesome to hear. And thats exactly what happened my truck was dumping that coolant out the cylinder for sure you could smell it out the exhaust. Now the only thing I'm worried about is I didn't realize it was drinking all my coolant so I managed to get it pretty hot as well so I'm not sure if there Is any other damage. how could that cup have moved though with everything being torqued down to spec?

 

Likely when you pulled the injectors the first time

 

Sounds like bad set of injectors and cups white smoke out of oil fill is blowby getting by the piston rings

 

It likely moved during injector removal without injector in the only thing that holds the cups in are a bead of loctite

 

Well tore it down and installed a new cup gaskets and a new injector and tested all others. and im still having an issue. When we took it out on the road to test her out i started out driving it easy and it got up to speed easily without a problem. But when i would STEP ON IT to get up going fast my truck would just die down and lose power. Im thinking i have another bad injector in it that they said tested okay. Im no expert at this but im getting good at pulling these injectors out . Any ideas on what would cause that please help??

 

Did you buy ebay remans? Thts a no no merchant auto bosh's or gm injectors only and highly suggest the cat fuel filter 2 micron kit