5.3l overheating problem
You either have a vacum leak on bank 1 or a bad o2, bad inj........
Stock 5.3l Envoy will run in the 14:1 AFR at WOT, because of PE delay. Its a simple fix in the tune though. You will more then likely need a custom tune to get it running right. Some one who can tell you what you are having problems with and fix it and get it running correctly. As far as the over heating you ahve a weird situation there that a friend of mine shares. He has a 5.3l in a S-10, he just got it running so we have not had time to explore the problem yet. I will keep you posted when we find something out.
Stock 5.3l Envoy will run in the 14:1 AFR at WOT, because of PE delay. Its a simple fix in the tune though. You will more then likely need a custom tune to get it running right. Some one who can tell you what you are having problems with and fix it and get it running correctly. As far as the over heating you ahve a weird situation there that a friend of mine shares. He has a 5.3l in a S-10, he just got it running so we have not had time to explore the problem yet. I will keep you posted when we find something out.
Most likely is a bad O2 sensor, a vacuum leak on one of the injectors (bad o-ring on the manifold side of the injector perhaps) could cause it too. Injector is possible as well, but I think you'd feel that in your acceleration and idle.
Swap the O2 sensors, see if it follows it.
FWIW I had a bad O2 giving me essentially the same reading. Still didn't cause any temperature problems. If it's not maxing the fuel trims, its likely finding it's way back to expected values with the added fuel (or the O2 is bad and it's running rich now), either one shouldn't cause massive overheating.
Swap the O2 sensors, see if it follows it.
FWIW I had a bad O2 giving me essentially the same reading. Still didn't cause any temperature problems. If it's not maxing the fuel trims, its likely finding it's way back to expected values with the added fuel (or the O2 is bad and it's running rich now), either one shouldn't cause massive overheating.
Thread Starter
Teching In
Joined: Feb 2008
Posts: 33
Likes: 0
From: Pottstown, PA
Checked for air leaks today. that didn't turn up anything. I am going to try the o2 swap tomorrow. If that doesn't have any effect I might try swapping injectors from side to side and see if that does anything. But It runs smooth like glass, so I don't think I have a major injector problem. But I am with you I don't think this problem is causing the heat problem....
That this continues to be a problem suggests bringing out the "trick bag"
- Take an IR thermometer and take a look at each of the cyls at the exhaust header to look for hot spots and bank-to-bank temp variation
- Spray carb cleaner around the intake to look for vacuum leaks. (You should be throwing DTCs if that was a problem.
- Verify the routing of your serp belt
- Assuming you're still at the 100% H20 stage, dump the cooling system, replace the heater "circuit" with a simple "U," raise the front end of the car and fill the system through the upper radiator hose (Disconnect at the radiator, hold it up and fill until water flows through the (open) rad cap.
Rev it up and watch the O2 voltage. If one of the sensors is not switching, it is bad. I would guess the side with 0% is bad. This would cause overheating issues if you are off by 18-20% like the other side says. If that is the case, you should get it retuned. Sounds like your inj. constant is off.
Thread Starter
Teching In
Joined: Feb 2008
Posts: 33
Likes: 0
From: Pottstown, PA
How long does it take for the long term fuel trim to "reset" after making changes? I swapped o2's around, checked for vacuum leaks. Should I see the change in long term fuel trim right away or does the computer need to relearn over some time?
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