horist

For those not familiar...

about 1.5 months ago I ran the car at the track for the first time... ran a whopping 13.3@102mph ... checked atap and as soon as I go WOT (TPS 4.5 volts) I get instant 4* KR and only 12 degrees of timing... I copied the high octane to low octane tables and then ran 12.3 w/only 22-24 degrees of timing....

So I pulled my intake the following week thinking maybe I crushed the wires for the knock sensors... nope, put 2 brand new Knock sensors in and tried it out... quickly same problem came back.

Few things I've noticed, if I give the car ANY gas cruising w/converter locked up the KR shoots up to 8 degrees then decreases, once it does this i can do the same thing (give it gas) and it stays at 0KR

Anytime I go WOT 4* instant even on 100 octane so it's not real knock, definetly a problem w/the system somewhere.

I am going to pull the intake again this weekend and trace all the wires.

The car is setting P0327 Knock sensor circuit low input code

Is this say 90% likely a wiring issue? Can anything else play havoc w/the knock system? (I read one post where a guy put a MAFT on his car, and had this problem, then took it off and it went away... i'm not running a MAFT but if my stock (screen and all) MAF is going south could this be a symptom?)

I'm going to try putting in my spare PCM (though I don't have an ls1 edit license for it so the car's going to run like crap) this weekend to see if it's PCM related (I hope not)... i'm just at wits end trying to diagnose this... I don't know how the knock system works exactly (how integrated it is w/other systems in the car) so want to check to see if there's anything else I should check that could be related!

Thanks!

horist

let me see that buuuuump... that bump da bump bump bump!

NoGo

iTrader: (2)

That sounds alot like a wiring problem or the ever ellusive PCM problem. You may have to run/replace the wires all the way from your PCM (check your PCM pins) to the knock sensors.

Good Luck

ChrisB

I would try buying a new knock sensor and re-running the wire from the pcm harness pin to the knock sensr first off.

EVIL

i have seen this happen when the knock sensor wire gets pinched under the intake. i personally did it on one car, no code, but it got knock.

i tuned a blower car and it was seeing 4.8 as sson as it was at WOT and i knew it wasnt real knock, and sure enough, the intake came off and there it was cut.


if you changed the sensors out already and are sure they arent getting cut or pinched (i would use some tape to hold them in place under the intake), then start checking the grounds on the back of the head then move on to the pcm and find the pin for the knock sensor.

JeremyF

iTrader: (23)

I believe it is real knock. I have seen many cars have this very problem. If I were you I would do 3 things: first I would decrease the PE threshold by 10-15%. second increase the accell enrich by a few % and then finally if none of this works I would retard the timing in the SPECIFIC area, it just may be as plain as there is too much cyl head pressure and therefore too much timing at that specific area. If you have turned the thing into a much more efficient breathing machine the instant rush of air needs to be calibrated for. The PCM does a very good job of calculating air and fuel flow but I feel it needs to be tweeked.

Jeremy Formato

98TAauto

iTrader: (2)

just a FYI, but with my heads/cam under any slight throttle with the verter locked ill see 4-8degrees of KR off and on.. Ive seen a few other cam cars do the same also. I just thought of it as normal. None set SES lights though... Good luck

BTW, i also found pullin timing in those specific areas like said above reduced knock also. But weather effects that alot also. In hotter weather the car is gonna knock worse

blk~2000~Z28

I do not know if this pertains to you but my 2000 Z28 kept throwing low input codes on a Knock sensor and I had 2 dealerships swear to me that it COULD be the high octane fuel I was using. This was the only explination they could give me considering I had a work order stating one of the dealerships had replaced the "culprit" Knock sensor. Although I had no way of proving that they indeed had. Their explination was that the sensors needed some input from the motor to set the timing, and if there was no input that it would throw the low input code(input being Knocks I guess?). Again they told me the reason it was not receiving input was because I was using '93 octane on a bone stock car and that switching to lower octane should alliviate this. I do not think though that my problem is related to your KR problem, it MAYBE though related to your low input problem.

Personally though I think both dealerships were full of ****, but then again I do not do warranty work on LS# engines for a living now do I!

HumpinSS

iTrader: (1)

Going to lower octane will do nothing but make the problem worse

Kobwo

A HIGHER octane helps control detonation more. I agree w/HumpinSS that LOWER makes it worse. Racing fuel isn't more volitile it actually helps control the increase in energy of high performance systems to prevent detonation. That dealer is full of S$!^.

horist

well i *think* i've got my issue isolated to the PCM...

I returned my LS1 Edited PCM to stock (put the stock tune back in it from last year when I first got LS1 Edit), and the issue still was there (set the P0327 DTC w/in 2 blocks)... i then put my spare PCM in (never touched w/LS1 Edit, flashed by dealer to stock tune) and it ran strong (though a 224 cam on a 112 LSA in an A4 idling at 550RPM doesn't work very well...) w/no SES for P0327 (just EVERY other SES hehe)... kept swapping PCMs back and forth and every time i'd put the modified PCM in (even w/stock tune) the P0327 would come on really soon after driving...

Drove for 100 miles on the spare non-modified PCM and it's fine... so I'm going to have the dealership reflash my other PCM to stock and try one more time... if it still have the problem then something's gotta be fubared w/my PCM

horist

GRRR not the PCM... replacement PCM set the code tonight...

so I'm looking at the wiring harness this weekend :/

purevilss

For the longest time, i was getting 4* KR at WOT and could not stop it. I found it being pulled by the IAT chart. When I zero'd out all the cells, no more KR. Just a thought!

horist

well all... I am pretty confident I have the problem licked!

Pulled my intake manifold off AGAIn today (mainly cause I had to put some 42lb injectors in) ... I wanted to inspect the Knock sensor wiring harness... went to pull it out (disconnected the connector behind drivers side head and the connections on both sensors) and it wouldn't give! WTF

So I disconnected the Cam Position sensor thinking maybe it was in the way... still nothing... gave it a little tug, was stuck between the block and the lifter valley cover!!!!!!

Took lifter valley cover off, and removed wireing harness...

What i found:
Dark Blue wire, copper wires exposed

Dark Blue wire is the wire that goes to the PCM for Front Knock Sensor... I was getting codes for JUST my front knock sensor!!!!

I'm about 30 mins from havin the car back together now, then I'll load my new tune in for the new injectors and we'll see what happens