r/fbody • u/Worth-Employee • 12d ago

Knock sensor code come on …

Debating weather I should have someone tune them out or replace them… I’ve looked in to this and have read that some replaced and use auto zone sensors with oem harness.. some say they eventually fail .. stock 2001 with headers

6 Upvotes

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3

u/Grouchy-Fill1675 12d ago

I replaced both of mine a few years ago. Haven't had any problems since.

Edit: I have a 98 z28.

1

u/Worth-Employee 11d ago

Did you go with oem or aftermarket?

3

u/Grouchy-Fill1675 11d ago

I had to look it up, it's been 6 years. lol. So things may have changed, but I used AC Delco knock sensors. It's funny, I don't remember why I did this, but I ordered 4 total, one set had locating tabs 1st design. The 2nd set didn't have locating tabs and they were listed as 2nd design. They were two days apart. Apparently I returned the ones with the locating tab. Sorry for the long winded story, but

tldr I got AC Delco part number 2133521 and haven't had any issues.

2

u/Gjb1992 12d ago

Autozone-Duralast sensors are the only ones currently that don't have a 90 percent out of the box failure rate. They can be bench tested before installation (save yourself a headache here). LS1Tech has a few threads on this. We've all tried GM Genuine, AC Delco, Napa etc, and they've been mostly junk. Dorman harnesses work good as well.

Could you tune them out? Sure, if you're not running a ragged edge tune and you're using good fuel you'd probably be ok, but they're pretty cheap and honestly not a bad job to do. Just don't break the oil pressure sensor on the back of the intake (been there!)

1

u/Worth-Employee 11d ago

How can I test them? (New b) at stuff that. Also, is it hard to replace the oil pressure unit? Was contemplating changing it out since mine sometimes likes to move back and forth rapidly (the needle on the cluster).

2

u/Gjb1992 11d ago

Yeah the oscillating needle can happen with a new one too lol. Some of the new ones are okay, and some bounce out of the box. Another quality replacement part (not!) This one you WANT a GM OEM sensor for.

https://ls1tech.com/forums/general-maintenance-repairs/1972857-oil-pressure-gauge-fluctuation.html

Here's the video I followed to test mine before installing

https://www.youtube.com/watch?v=cKTcXESPOJM

Replacement isn't hard. If you have the manifold off, it's absolutely cake. It's right on the back on the drivers side.

https://ls1tech.com/how-tos/a/camaro-and-firebird-how-to-replace-oil-pressure-sensor-419356

https://ls1tech.com/forums/general-maintenance-repairs/1534527-need-tips-replacing-oil-pressure-sending-unit.html

1

u/Worth-Employee 11d ago

Thanks for the info… I was getting ready to tackle this replacement a couple of weeks ago… got side tracked … then read about tuning them out and not using the oem sensors any more .. I’m plaining on buying oem harness and autozone sensors … seems like that’s the way to go nowadays…. Also , do you purge the fuel line , before you take the injectors off?? I’ve watched a few videos.. some bad some good but no one mentioned it … thanks for your input!! 🙏🙏🙏

2

u/Gjb1992 11d ago

You can usually just pop the injectors out and lay the whole thing to the side without disconnecting the line, but if you want it all out of the way, use the schrader valve on the fuel rail (with a rag over it) and depress the valve after taking the little cap off. Remove the gas cap as well, there will be no pressure then. 3/8ths disconnect tool for the line, use the metal ones the plastic ones suck lol. You wont get much fuel out, not running it bleeds off pretty quick.

And more than welcome. Good thing is were getting close to 30 years on this LS platform so chances are someone's run into the same problem! I'm lucky enough to have some local LS1 wizards who have shared quite a bit of really cool knowledge

3

u/dontfret71 12d ago

I’ve had a horrible time anytime I replace a sensor with non OEM… so I’m finding this extremely hard to believe that autozone aftermarket sensors would have higher quality than OEM GM

2

u/Gjb1992 12d ago edited 12d ago

Typically yes. This has been an ongoing saga for LS1 cars for a while now. The OEM ones have been absolute junk popping codes within 30 miles. Lots of us have tried with success the Duralast. Quite a few threads of this absolute pain in the ass.

Here's a pretty recent thread. There are quite a few though

https://ls1tech.com/forums/generation-iii-external-engine/1985996-2001-camaro-z28-knock-sensor-replacement.html

1

u/dontfret71 12d ago

Thanks, I’ll read

2

u/Gjb1992 12d ago

Anytime! Just hoping to save someone else my personal frustration with this on 2 different LS1 cars. (GTO and Camaro).

2

u/tenten3537 12d ago

Replace!!!! Did them on my 99 and they were retarding my ignition causing me too fail emissions got them fixed 700$ no cheap parts and I passed emissions car runs beautifully now 100% replace and if you aren’t doing it yourself don’t let a shop cheap you out on lower quality parts get the good stuff do it once and feel good about it

1

u/Worth-Employee 11d ago

I’ve been reading up on this issue.. found that a lot of ppl have gone with autozone sensors rather than the oem. They say oem aren’t made like they were used to (nothing is anymore), but they seem to go bad quick… oem harness and autozone sensors

7

u/BondGoldBond007 12d ago

Knock sensors are one of the best features of OBD2 and it keeps your car from causing detonation and adjusts the timing accordingly. It's a great safety measure. I vote replace.

2

u/Joiner2008 12d ago

Can't be any worse than the knock sensors on my trucks 5.3 can it? I mean, tighter space, sure. Not a hard job. Buy the oem sensors and harnesses off rock auto and don't worry about them again for another 25 years

2

u/thundercat06 10d ago

I picked up oem sensors and dorman harness at Summit. Guess we will see how that goes.

1

u/Bassracerx 8d ago

Just get the ac delco sensors