false knock??

[grazi]

I'm trying to track down the cause of spark retard-15 degrees at times...
Noticed I'm getting up to 4 degrees of retard in neutral while lightly revving motor with long and short fuel trims right at 128 (Not running lean)Does that mean its a false knock or possibly a bad knock sensor?

[LTb1ow]

What kind of car? Mods done to it? Last tune up? Ect.

[WildBillyT]

Mod list?

[grazi]

94 TA 102,000 miles....A4. bone stock except SLP CAI...
Just did:
ECT sensor
IAC valve
EGR Valve
EGR solenoid valve and vacuum lines
O2 sensors.
Fuel filter
Cleaned MAF
Replaced PCV and CCV hoses
Havent done plugs/wires yet, probably due

[WildBillyT]

Have you checked the fuel pressure?

[grazi]

http://www.njfboa.org/WBT/run2.uni
Heres a Datamaster run

[grazi]

Yes fuel pressure 40 at idle and 45 at WOT going off memory

[S.J.SLEEPER]

I have heard in the past that lt1 knocks were sensitive and guys ran the lt4 knocks to solve the problem. But, I may be wrong, I really don't concentrate on retaining boat anchor information...lol

[LTb1ow]

I have heard in the past that lt1 knocks were sensitive and guys ran the lt4 knocks to solve the problem. But, I may be wrong, I really don't concentrate on retaining boat anchor information...lol

Meh.

If he had roller rockers or even long tube headers maybe. But stock sensor and module should be 100% fine.

[grazi]

Couldnt the stock sensor fail over time??

[grazi]

I just turned off the sun and ran car in dark. When I revved it I could see the spark plug wires arcing in a couple spots so I guess thats next on my list and what is causing my problems. Im going to buy NGK TR55 plugs . Anybody have suggestions on wire brand/size....How bout gapping of plugs.... .045?

[sweetbmxrider]

Msd's and yeah that's fine.

[grazi]

Cool thanks

[RamAir95TA]

Gapped at .050".

What octane fuel are you using? Might be a good idea to use some 100+ octane and see how that affects your knock readings. If it goes away then the knock is real. If it stays, the knock is false.

[sweetbmxrider]

.050 is stock and way big.

[grazi]

I'm gonna do .45 .. I think the NGk TR55's are pre gapped .59...Ram Air I'm using 93 now. After I do plugs and wires this week, I'll see how it runs but I'm pretty sure thats where my prob is coming from.

[RamAir95TA]

His car is stock...how is .050" too big? :confused: Makes no sense.

I ran mine gapped at .050" bolt-on only for 5 years running well into the 12s. Nothing wrong with .050".

[sweetbmxrider]

Stock coil is questionable at high rpm. Might as well help it out with narrowing the gap it has to jump.

[grazi]

Bolt on LT-1 run 12's?

[RamAir95TA]

Bolt on LT-1 run 12's?

Sure. There's even a handful in the 11s. Good parts, tuning, and suspension and 12s are easily attainable.

[z28camaro94]

had the same problem a couple of years ago when my dad owned the car.

did the plugs, wires, upgraded the opti while we were in there and did the lt4 knock sensor and module. the prob went away...cant specifically say which part did it for me but sounds like ur on the right path

[grazi]

Thats good 2 hear. Thanks. Stupid question-when you guys replace the knock sensor, if your fast enough, could you theoretically not drain coolant and just work fast and let some spill and replace what you spilt? I did that with my ECT sensor and only lost a little coolant.

[sweetbmxrider]

In theory, I would do that with a clean pan in the "drop" zone.

[grazi]

AKA just do it in the grass?

[sweetbmxrider]

In the "grass", ya.

[grazi]

...

[grazi]

Update: I just replaced the plugs with NGK TR55's gapped at .045. Replaced wires with MSD Street Fire.. Still having the same hesitation and bogging issue. Didnt hook up Datamaster yet but seems like computer is retarding timing real bad still....
If I disconnect the knock sensor and ECM stops pulling timing does that mean that I either have a faulty knock sensor or a real problem that is being picked up the KS? Would I be able to hear an audible knock before I potentially damage motor if there is a real problem.
Thanks for the help