Mat

Hey all.. just figured I'd throw up a couple images from one of my many HPTuners sessions. I'm pulling 4* KR at WOT and the car has been doing this for what seems to be the last two years. Being I have a 1998, and have done a pile of reading and searching I'm willing to be this is because I have the older crappy knocks in the car.

At any rate, I only see 24 degree's of timing at WOT which isn't a good thing as if I added the 4 back in it'd be 28 which is what I should see. My friend's 1999 TA doesn't do this at all. I've done VE tuning on the car too now and I'm no closer to where I want to be. Here's some attached scans... am I thinking along the right lines?





Thoughts?

dvanorder

When was your 98 built? My 98 has it just at WOT too; it was built 6/18/98. My understanding is it would already have the 99 sensors. Most of the 98 sensor false knock I've been reading about has been throughout the range, not just at WOT.

Since my tune is solid and fueling's not lean, I'm considering desensitizing the sensors. It's also possible there's a little exhaust noise coming back through the manifold but sure couldn't hear anything over the Stingers on the dyno

Crash Dummy

Try adding some more fuel @ 4000 Hows the fuel filter ?

Mat

Hmm.. not sure when mine was built.. where can I check that? The door sticker?

I agree, you'd think it'd be throughout the range..

As for the fuel filter I've never changed it or checked it. The car has about 47,000 miles on it right now.. maybe that's the culprit?

Crash Dummy

47,000 I would go to the filter first and change it, I change mine every 20,000

Mat

Hmm good call. What type is recommended or would you recommend? They're at the back in the hard line after the tank right? Any special changing procedure or link I could look at?

Thanks man.. I'll try that first and see where I end up...

Crash Dummy

Go with the factory AC unit they are known to be good

RedHardSupra

iTrader: (1)

put in 100 octane, see if it still does it

Another_User

Looks like false knock to me. My car had that problem. It would ever ride the low octane table, plus take away 4 degrees of timing. I tuned it out. No problems.

Crash Dummy

Show you AFR table that will help alot.

Grimes

iTrader: (3)

Just be prepared to get a lot of gas on you, lol. It's good to have some standard size flare nut wrenches so you don't take the chance of rounding off the fittings. Also, after I monkeyed around with mine a bit, the filter will have leeway towards the rear of the car - so just disconnect the front fitting and push the filter back for more room. Took me 15min and a gallon of gas to figure that out!

dvanorder

If you give the VIN to a dealer, they may look up the date for you over the phone (did it for me). There are some guys over in the Corvetteforum that will do it for Y bodies, I'll bet there are F body forums where you can get the same favor.

dvanorder

By tuning out, do you mean desensitizing the knock sensors, or did you do something else? On the dyno, my AFR was 11.8 at WOT.

Another_User

Desensitized the knock sensors through tuning with HPTuners. Very easy on 98s.

Sport Side

iTrader: (6)

Would you be able to go on to tell us which tables you changed? Which were the most effective in releaving the KR?

Thanks.

Another_User

Knock Sensor Global Gain vs. MAP vs. Cyl, table values changed to 4 from 65kpa up.

Sport Side

iTrader: (6)

Thanks.

dvanorder

Ditto!

Blown Interceptor

iTrader: (5)

Thanks for the info...I also have a 98 with some false knock. Tuners is on the way.

Mat

Ahh gotcha! Thanks for the info there!

As for the other recommendations (thanks RedHardSupra!) I usually run 94 octane in it and I don't have easy access to higher octane fuels around here (nearest drag strip is about an hour and a half away). I could always do some home-brew high octane by mixing Tolulene into the tank...

As for my AFR table.. will that tell you guys anything with the narrowbands only? I'll post it at any rate though!

Here we are:



Thanks for all the responses guys! I'm gonna pick up a new fuel filter today at any rate! Keep'em comin!