Ali SC3

iTrader: (10)

I wasn't 100% sure where it was I thought I read they went to the ecu but I know they are grounded somewhere on the harness side, not at the plug/connector end of the wires. I generally just connect them back together and rely on the original shielding ground in the harness wherever it is, that the point is you don't have to know where it was as long as you connect it back together. grounding in new places on the block could pick up more noise or create a ground loop if that is not the original spot, but if you know they are grounded to the block/intake you would be ok for the most part doing that but generally speaking I avoid it.

without knowing exactly where I usually just connect them back to the original connection without trying to make a new path. good to know though if its off the intake though and not the ecu I guess its not that special of a ground.

CLRH2O

This is good info guys. Particularly the CL Discount... why didn't I know about that?!

As for Matsu****a - it appears that they were the OEM parts manufacturer for Toyota Lexus during the time these cars were in production.

And yes - I SERIOUSLY don't want to go through the whole top of the motor tear-down a second time due to missing something or messing something up. In fact, I'm so against it, I've already bought everything I need to do the entire top of motor seal and gasket rebuilt (valve sleeves, Plug and valve cover gaskets, ect ect ect.

Ali SC3 - the one thing I don't know for sure is if both sensors (or really, if it's possibly just the wiring) have gone bad. That's the trouble with these older ODB-I motors... there's so little information about what exactly is happening. Sure, it gives code 52, but that's not definitively the knock sensor. So my plan is buy EVERYTHING and just cover it all. This method is seriously taxing on the wallet compared to a surgical strike - but I'll have all new parts in all places as a result... And really, on a 22 year old car - probably good idea regardless

Ali SC3

iTrader: (10)

that is true you never really know with the obd1 ecu's. how does it run generally though? sometimes a bad ecu can trip the knock sensor codes.

CLRH2O

I had the ECU rebuilt about a year and half ago - although I've maybe driven the car a total of 10 days over that period time so I cant really say if it was a good rebuild with those really super special wizz-bang capacitors the one guy on here figured out you HAVE to use or it all goes sideways again or not.

Otherwise however - the car is stout and before the CEL comes up it's the same old bruiser when pushed hard

jomosc400

Sure would love to know what happened with this guys harness. Perhaps he could chime in with some good information for us still struggling to find a solution to the elusive unicorn known as the SC400 Knock Sensor Harness.

Sherl

What did you do?