I am taking the TPI setup off of my 86 305 and putting it on a 350 from a 78 Z28. I'll be upgrading the cam, rotating assembly, and a buddy of mive will burn a custom chip for it... but I am concerned about the knock sensor.
What does it do?
Where is it located?
How do I swap it?


Any help with these questions will be appreciated.

Thanks
Dan

 

THE OLDER BLOCK WILL HAVE A PROVISION FOR THE KNOCK SENSOR, YOU JUST NEED TO REMOVE ONE OF THE PLUGS ON THE PASSENGER SIDE OF THE BLOCK BEHIND THE MOTOR MOUNT PAD.

 

Thanks a lot for the help there.

Now will the sensor from my 305 work on the 350 or do I need to go to like Affro Zone and pick up a new one?

 

THAT SEEMS TO BE A TOPIC OF DEBATE... TPIS SAYS THAT THERE IS NO DIFFERENCE BETWEEN THE 305 AND 350 KNOCK SENSORS. SEVERAL PEOPLE ON THIS BOARD SAY THERE IS A DIFFERENCE. I AM CURRENTLY RUNNING MY 305 KNOCK SENSOR, AND HAVE GONE DOWN THE TRACK AT 12.4, WHICH WOULD MAYBE BE BETTER BY REPLACING IT, BUT I DON'T KNOW. FOR $20 THOUGH, YOU MAY AS WELL REPLACE IT DURING YOUR SWAP. I'LL PROBABLY DO MINE AFTER MY FIRST WEEKEND AT THE STRIP TO GATHER MY NEW BASELINE (GOING SOLID), AND THEN RUN IT AFTER THE KNOCK SENSOR.

 

I would like a definative answer to whether or not the 305 and 350 sensors are different or not...

BTW, you may, depending on exhaust headers need to mount the KS in the driver's side of the block. When I put the Hooker LTs on my Camaro, I needed to relocate it to the DS, comes from the factory on the PS down by the oil pan rail. BTW, my block is an 80 and there are not problems mounting anything, other than an oil pan!!!

 

according to affro zone as it was deservingly called the 305 knock sensor and the 350 knock sensor have 2 different part numbers so theres a difference somewhere

 

Yes there is a difference besides the part number.

The 305 and 350 knock sensor is sensitive to a unique frequency each engine produces during detonation. So, a 305 knock sensor will not necessarily work in a 350 engine since it's listening for a 305 detonation frequency. When the knock sensor finds a detonation frequency, I believe the ESC (Electronic Spark Control) module will retard your timing.

That's another part you'll need too. The ESC module.

Check Ed's post here:

https://www.thirdgen.org/techbb2/sho...ck+sensor+ohms

That's a really good explaination of what the knock sensor does.

 

COOL. I WILL HAVE HARD EVIDENCE THIS SPRING BECAUSE I'M GOING TO RUN WITH THE 305 KS, AND THEN THE 350 KS TO SEE IF I'LL PICK UP ANY TIME IMPROVEMENT. ALTHOUGH, I DON'T BELIEVE THAT I HAD MUCH OF A KNOCK COUNT WHEN I HAD A SCANNER HOOKED UP.

 

I always heard the eng bore determined the knock frequency, so a 305 and a 350 would be different.

The year makes a difference too. Late model knock sensors have 3.9k ohms resistance and the earlier models have ~100K ohms.
If you have an external ESC module under the hood, you'll need a 100K ohm.
The later models have a chip on the Memcal that replaces the underhood ESC module. They use the 3.9k ohm knock sensor.

Until your sastified you have the knock sensor system working right, you might wanna pull the plugs frequently and check them for signs of detonation.

I didn't think I was detonating. Never heard a single knock, but when I pulled the plugs and viewed them with a hand-held microscope, I was shocked!

If you are handy with a soldering iron, you can make a stand-alone knock sensor system for abt $60 ($30 for sensor and abt $30 for the parts).
I'm convinced that I saved my new eng by installing one.

 

Can you describe in detail how you accomplished this???

 

TAKEN FROM THE LINK ABOVE:


As for my car... all it was was my knock sensor. Tested my KS and it didn't have any resistance. I put my old 305 one in and it works fine. The knock retard I was getting b4 for no apparant reason is gone too! I guess the ECM retarded the timing b/c it knew that the KS wasn't working. Does this make sense to anyone?? Well, thats it.

BTW-The GM tech manual I used said the KS should have like 3000-5000 ohms resistance and should have 4-6 volts going to it from the ECM. Thats it, later.


THE OWNER OF THIS CAR HAS A 355 IN IT, AND HE SWAPPED IN HIS 305 KS.....

 

Here's the schematic. I used a regular L98 knock sensor screwed into the drivers side of the block. The pass side knock sensor is still connected to the ESC/ECM.
I have more pics of the project. If your interested, I can email them to ya.