jdmsuper7

iTrader: (1)

I installed my S-AFC earlier this week and it ran fine for about 10 minutes and then threw a CEL which turned out to be code 5 which is for the knock sensor. The engine starts with no light but throws the CEL as soon as I put a load on it. I figured that I had somehow screwed up the splice and I dug into that today. I first checked the pin into the ECU and found no play in it. I re-soldered the splice and still got the light, I then removed the S-AFC wire and really beefed up the solder on the harness wire and still got the CEL. My question now is how does that sensor work? Could the actual knock sensor go bad?

The S-AFC reading on the knock (I don't know how realiable that is) is also really bizarre. The car starts out with zero knock reading but then the reading slowly increases as I drive, going from a steady 0 to a steady 20 or so in the space of 15 min. When I initially calibrated the S-AFC reading, it seemed like it was rather odd there too since it started in the 20s, and when I held the car at revs to calibrate it, it jumped into the 50s and stayed there even after i dropped the revs back down, which didn't sound right according the the manual. I'd like to think that the knock CEL is related to the S-AFC, but after disconnecting it and still getting the code, I'm not so sure.

Any input would be great, sorry for the book.

-Nick

S5 turbo swap w/harness, no emissions

sleejay

check your safc wire to the knock sensor wire.
also check the safc grounds and your ecu grounds.
did you use shitty wire taps, or did you strip and solder everything?

jdmsuper7

iTrader: (1)

Everything was stripped and soldered, the rest of the AFC functions work fine. I'm really curious as to what the knock sensor actual outputs, so I can find out if the sensor is bad or if I have a REALLY sneaky wiring issue that cropped up. I checked the grounds and such 1st thing.

ilike2eatricers

the SAFC has a knock counter not knock sensor and it is close to useless

Sleeper69

Ive never used an SAFC but if it is really reading knock from the sensor you should be able to see the knock reading go up while the car is running if you have an assistant rap on the intake manifold with a hammer.

You could also have a bad motor mount. FC's are notorious for having broken motor mounts. That could cause you to read plenty of false knock. I didn't even think the FC had a knock sensor though.

sleejay

yes it has a knock sensor, a horrible old one.
it only does anything low to mid rpm.

Aaron Cake

iTrader: (1)

The knock sensor has a shielded wire. Did you accidentally tie into the shield instead of the inner wire?

jdmsuper7

iTrader: (1)

I'm goin to look at that now, thanks Aaron

jdmsuper7

iTrader: (1)

Ok, I'm seeing the insulation and the actual wire and it seems I managed to sauder thte both of them together along with teh AFC wire. This may be a dumb question but would splicing the main wire to the insulation wire cause enough interference to throw the code? Also, how do I fix it? Am I gonna hvae to cut out the offending section and solder a new section in taking great care to only get the main wire? Or is there an easier way?