semvhu

Here's the story, I'll try to keep it short. Recently in my bone stock '94 coupe, my dad and I did a lot of work on the coolant system. When it came time to drain the coolant and re-fill it, I decided replacing the knock sensors would be a good idea. I'd read online about using those from an LT4 instead because they were of higher quality, so my dad and I go to the Chevy dealer and grab two for a '96 model. The dealer showed only one sensor was used for that year per engine instead of two like in the '94, and the same number was listed for the LT4 as the LT1.

Anyway, we get them, install them and refill the coolant, get everything ready and crank her up. She sounds kinda sick and immediately the check engine light comes on. I've no diagnostic tool, but we had a pretty good idea of what was wrong. I drove it to the highway, started going, and the thing was knocking and pinging like crazy, so I immediately turned around and limped back to the house.

The next day, my dad put the old ones back in and she ran like a champ. Now I'm pretty much out $60 :mad unless I can sell them to someone on here. ;)

Now's the meat of the matter. I've read quite a few posts on here about people saying put the LT4 knock sensor in LT1's. Maybe this has already extensively been covered and I just haven't noticed it because I'm new, but how much truth is there to this? Obviously, unless I did something wrong, a '96 LT4 knock sensor does not work with a '94 LT1. Will it work with a '95? Do the '96 LT4 and LT1 use the same sensor? Some food for thought.

I get online that week and look it up. Most of you probably already have realized my confusion. A good replacement is to use the LT4 knock MODULE for the LT1's, and I read many articles online where people had replaced their '94 knock module with a '96 LT4.

For any of you considering this, please research and know what you're doing. When I did it, I was going off of something I'd glanced at some months ago, not something I had researched and was supposed to be accurate.

Don't replace your '94 knock sensor with a '96! I know from experience, and you’ll just be out at least $50. :smash: :lol:

Goody

I only ask this, did you put any sealant on the new sensors and where you careful about torqing them to specs?

93LT1

So if you install the 96 knock sensor and module then everything should be fine? I wonder if this combo would work on a 93 ?
Hmm

semvhu

We put no sealant on them and we had no idea what the torque specs are. The bolt portion of the sensor had some sort of rubber-like ... stuff (I'm totally brain dead right now, must need some sleep) on the threads and we assumed that was good enough. My dad torqued them down with a ratchet; the old ones torqued back on work just fine, so I assume the amount of torque he put on the old ones should be good enough for the new ones.

The shop manual just says to take the old ones out and put the new ones in after draining the coolant. It says nothing about sealant and I noticed nowhere that it mentioned torque specifications, but that doesn't mean I couldn't have overlooked the torque specs.

Thanks for the good questions. Now a return question: SHOULD a '96 knock SENSOR work on a '94 LT1? After the problems I had with it, I assumed its sensitivity was just different than that of a '94 model.

Thanks!

semvhu

Sorry for missing your question, 93LT1. From what I've read, people replace only the knock module, not both. From my understanding (educated guessing after working in measurement systems a few years), the knock sensor is an accelerometer, and the knock module is the signal-conditioning circuitry. I'm guessing that if the '96 and '94 knock sensors are different, they just have different sensitivities, maybe with the '96 being more sensitive. The knock module sensitivities must be the same, but the '96 LT4 module must have a better filter on it to be able to pass true knock and block fake knocks, such as hard bumps in the road or a bouncing exhaust pipe.

Can anyone confirm this? These are just educated guesses; I'd look it up, but I'm pretty frickin' lazy right now. :smash:

Oh, and your question about it fitting on a '93: I've read that '94 - '96 are similar designs, but '93 didn't have the knock module like '94 - '96. Someone correct me if I'm wrong there.

MJ

no, not with a '94 PCM
not applicable to the '93

93LT1

Thanks Guys

R23HTC

I have '94 knock sensors and a LT-4 ('96) knock module installed in my PCM.

The LT-4 knock module isn't as sensitive as the earlier ones. It was designed that way because the roller rockers can cause false knock.