Anyone with any altitude knowledge enter!
Thread Starter
TECH Apprentice
Joined: Jun 2002
Posts: 301
Likes: 0
From: Fayetteville, NC
Anyone with any altitude knowledge enter! I had my SS tuned in Las vegas, which is 2200 FtMSL. I just moved to Florida and since I have been here it has been running like ***. There I had no knock or any other problems. And it was tuned on 91 octane. Here I have 93 octane, and it runs bad, It puffs smoke when I try to get on it, I have KR everywhere and when I cruise at say 85 on the interstate my converter will not stay locked up. It will lock for a few minutes, unlock and rev about 400 RPM, for a couple miles and lock back up. Any Ideas???
Yup.
When I lived in Amarillo (3700', typical DA of 5000+ ft), I was able to run a lot of timing on the 91 octane there. Going to lower altitudes, I had to take out timing to get things to stop pinging. So what you're experiencing is normal, IMO. Get it retuned ASAP.
As for the converter, if it's running bad enough, misfires will keep it from locking up. Again, you need a retune. There are some LS1 tuners in Florida (Norris Motorsports comes to mind).
-Andrew
When I lived in Amarillo (3700', typical DA of 5000+ ft), I was able to run a lot of timing on the 91 octane there. Going to lower altitudes, I had to take out timing to get things to stop pinging. So what you're experiencing is normal, IMO. Get it retuned ASAP.
As for the converter, if it's running bad enough, misfires will keep it from locking up. Again, you need a retune. There are some LS1 tuners in Florida (Norris Motorsports comes to mind).
-Andrew
Thread Starter
TECH Apprentice
Joined: Jun 2002
Posts: 301
Likes: 0
From: Fayetteville, NC
Well, i am only running stock timing and I thought that the oxygen sensors would keep the part throttle stuff inline? This is where I get my converter unlocking. Damn, I will try and add a lil fuel with the IFR tables tomorrow and see how that helps out.
Teching In
Joined: Dec 2001
Posts: 387
Likes: 0
From: Southern IN, USA
The system will compensate for changing pressures, and the level of oxygen in the air differences are negligible. You probablly are seeing results from different formulations of fuel.
Any smoke from exhaust at WOT is bad (unless you are flooring granny's Oldsmobile for the first time in 20 years...). Are you throwing any codes - it seems you have bigger probs than altitude!
Any smoke from exhaust at WOT is bad (unless you are flooring granny's Oldsmobile for the first time in 20 years...). Are you throwing any codes - it seems you have bigger probs than altitude!
Most likely, you will have to get the car retuned.
Although the car is setup to compensate for changes in ambient pressure, these compensations, especially with a cam, and exhaust are weak at best.
You will most likley have to get your fueling straightened out first. O2 sensors do compensate properly for fuel on a near stock car, but modified exhausts / MAF / etc... throw off the LTerm correction. So when moderately modified, it is best to keep your LTerm corrections to a minimum. Coming from a custom tune at a high elevation your fueling is most likely scewed slightly.
Once you have the fueling straightened out (if it requires it) then you will have to look at your timing. You have a H/C and depending on your compression the stock timing tables may be a little much. Especially being a 2000 your stock WOT timing is 28 deg. I have had to set several H/C packages to 24 deg overal timing due to > 11:1 compressions.
IMO, don't sweat the smoke until you get your problems straightened out. If you are seeing loads of knock retard (due to your poor fueling and perhaps over aggressive timing) then it is not uncommon to see smoke when you get on it. The PCM purposely overcompensates timing when it sees Load knock (anything over 4 deg is ALWAYS load knock). The less-than-optimal timing often causes misfires (which is causing your converter to lock and unlock) and will push some smoke out due to incomplete combustion.
Don't get in a sweat just yet. Get the car retuned, and see where you are then.
Good Luck
Although the car is setup to compensate for changes in ambient pressure, these compensations, especially with a cam, and exhaust are weak at best.
You will most likley have to get your fueling straightened out first. O2 sensors do compensate properly for fuel on a near stock car, but modified exhausts / MAF / etc... throw off the LTerm correction. So when moderately modified, it is best to keep your LTerm corrections to a minimum. Coming from a custom tune at a high elevation your fueling is most likely scewed slightly.
Once you have the fueling straightened out (if it requires it) then you will have to look at your timing. You have a H/C and depending on your compression the stock timing tables may be a little much. Especially being a 2000 your stock WOT timing is 28 deg. I have had to set several H/C packages to 24 deg overal timing due to > 11:1 compressions.
IMO, don't sweat the smoke until you get your problems straightened out. If you are seeing loads of knock retard (due to your poor fueling and perhaps over aggressive timing) then it is not uncommon to see smoke when you get on it. The PCM purposely overcompensates timing when it sees Load knock (anything over 4 deg is ALWAYS load knock). The less-than-optimal timing often causes misfires (which is causing your converter to lock and unlock) and will push some smoke out due to incomplete combustion.
Don't get in a sweat just yet. Get the car retuned, and see where you are then.
Good Luck
