avnger21

yes maybe i'm gonna get some crap about this sayin to SEARCH but i have done that and havent found my answer. My check engine light came on after washing my engine and its my knock sensor. so I wanna change it this weekend but have a few questions. How do I deal with the injectors to take the manifold off? do i need to pull every injector out or does the manifold come out with them still intact? is there anything I need to becareful not to mess up while doing this? and about the foam that it has under the manifold, is it better to just take them off or leave them on? any help will be greatly appreciated. thanks

Atomic

iTrader: (42)

Just unplug the electrical connections on the injectors, the whole manifold (rails, injectors, tb) lifts off as one. Dont think the foam really matters, I would leave it though.

mhotrodscooter

iTrader: (13)

You can pull the intake with the injectors in place.. I would change the knock sensor wiring harness to while ur there.. As for the foam under the intake that's up to you. I removed mine, but I don't wash my motor either.

SILVERADO11

This is good info, I ended up doing the job 3 times, first time i pulled the intake and installed one new knock sensor, still had a code, so i pulled it agean and installed the other new knock sensor thought for sure i had it fixed because i now had both new knock sensors, guess agean! i still had the code come back on after clearing it and driving it. I removed the intake for the third time (i was starting to get pretty damn good at it) this time and installed the new knock sensor harness and havent had a problem since.

avnger21

alright then thanks guys.... anything else I need to whatch out for? i read it is recommended to put sylicone around the sensors.., is this true? and obviously OEM sensors are much better than Autozone or other auto parts stores but has anyone used non-OEM sensors and had problems? I called the dealership and it comes up to about $212 for both sensors and harness but at the auto parts store i can get everything for about $100 less. is it worth saving the $$$ or is it common to have problems in the future by going the cheaper way?

mhotrodscooter

iTrader: (13)

You can put alittle around the boots to keep moisture out. I'd go with the OEM, cheaper is not always better. You may want to change intake gaskets as well, but it up to you..

Mrgoodwrench3

You should use AC Delco sensors and get a new jumper harness too. The torque is critical on the sensors. Spec is 15 ft lb.
Do not remove the fuel rail from the manifold. I would get some new intake gaskets
from GM. Make sure the rubber is green.

TX Tahoe Z71

iTrader: (28)

Try GM parts direct dot com. They are usually cheaper than the dealer. And don't overtighten the sensors, 15lbs only, and no thread-lock on them either. RTV around the rubber grommet is a good way to keep future moisture out.

JoeGibbSilverado

iTrader: (9)

i used "parts shack" sensors, got my intake gaskets there also, (felpro), and had my wife get a new harness through her work, the job looks overwhelming..but its very simple, 15 lbs as mentioned, i used silicone to seal the rubber also, also put some around the wire where it goes through the grommet, ive had zero issues

avnger21

so does anyone have a part# for the harness? GMpartsdirect.com has them for half the price as the dealer so I might go with them instead. anyone know how long it takes them to ship the parts?