383 TPI running 730 and $8D code

My question is:

When I'm accelerating heavy steadily(like 25-35%), I get knock counts due to the fact that I am leaning out on the wideband, but according to datalogs I am at 128.

What would be the best way to cover for this? It is below my current PE threshold(obviously). Should I cover it in the main VE table to bring it back to 14.6-14.7 on the wideband?

Just wondering if other people had this particular issue and what they did to solve it?

Only seems to become an issue over like 2400 rpm. All other tables tuned succesfully in the 120-128 range and I never get any flake outs or lean spots.

thanks
Jeremy

 

never had that problem.


...remember, knock counts does not mean there is engine detonation. Since the WB is reading lean and the state is steady, I would just add fuel via VE tables. See if the knock counts go down.

 

Exactly what I was asking :-)

The knock was occuring when I could verify I was lean. I would rather re test using a corrected(ie non lean) ve table and retrying rather than band aiding things or by pulling the itming, knowing I am lean.

later
Jeremy

 

Yeah, I'd start out adding fuel as well. Question is though, why is the NB reading generating 128 BLMs?

 

You might have BLM correction and never see that added fuel in closed loop. What are you goin to do if that happens? To me, the first step is to add the fuel and recheck knock counts. Run the entire test again to confirm the results. Then it's a real easy(tuning) decision at that point.

 

What are you trying to do with the car?.
Is it a Hotrod, or a go to work car?.

If it's a hotrod, then just run open loop, and taylor the VE to the AFRs that make it run best. That also might mean drastically lowering the TPS PE enable.

If your looking for MPG, then you'll want to run the least timing, to keep you out of detonation.

If you want good drivibility, you'll probably use more fuel then an econo queen would.

 

I'm trying to build a mileage/driver tune for it :-) If I was employed currently this one would be splitting driving duties with the squaturn :-)

I can change and play as I wish if I hit the dragstrip(july 9th) and/or road course.

Trying to make a nice safe conservative tune and work out as much knock as possible and still retain excellent manners and no lean out or knocking areas in the tune. This is the only thing really rubbing me raw on the whole tune thus far.

The WOT is about where I want it the low speed part throttle and idle are great. Just the midrangish medium to heavy non PE accel stuff giving me some fits right now.

If I get a chance and gas prices remain low(they just jumped here) I will add fuel according to datalogs and then repeat the test and see what happens

later
Jeremy

 

You missed, and generating *world peace*.

Rich with some extra timing, always generates what folks consider *excellent manners*. Which is just the opposite of MPG.

With what you've said, then pulling timing until drivibility suffers is what you need too do.

Just remember lean, means more timing, and that puts more heat into the chamber/ piston. And a the hotter the piston dome, the hotter the oil gets below it. Excesive oil temps., are a bad thing.

 

Have I told you its runs on hydrogen and water and roses come out my tailpipes :-) lol

Actually I'm getting some rpm drops when I was doing this and they correlate to almost the exact mph the TCC would lock.

Tracking TPS% vs. TCC lockup (appears to be TCC unlock prevent)and going to redo the entire scenario to make sure the TCC wasnt what locked up on me making it lean out and knock....

If it isnt one thing its another.

later
Jeremy

 

maybe the TC lockup is engaging rough. Bad motor/trans mount? I'm very sceptical on the accuracy of a P4 KS "system"....

......seems like 9/10 times it's actually false knocks. Even the 1 KS LT1's generate alot of false knock counts(usually @ the transition to WOT).

My personal view is that knock sensors are useless. I have seen many cars with false knock. Have seen cars with knock sensors detonating like a ****. Know that carburated engines does not need or use a KS. Usually if you get a bad tank of gas (or other problems) there will be detonation, with or without a KS. The best thing is to learn how to sense it yourself.

.....sorry for the rant..