Fuel Trims Crazy???

[01ssreda4]

Quickly looking at it, trims seem normal at idle, upon light acceleration they go pretty negative meaning you are running rich so its pulling fuel. Something else seems off.

 

[swathdiver]

Could an exhaust leak above the O2 sensors cause this? Do the O2 sensors seem lazy?

BlackBear asked for another data log on 93 octane be sent for evaluation. I just filled up with E85 so it'll take a bit to get the tank back to 100% gasoline.

 

[Scottydoggs]

exhaust leaks are never good. pre o2 even worse. can mess up the trims for sure.

you got snapped off manifold bolts? like we all do at some point...thanks gm.

 

[Rocket Man]

Following. I'm only beginning to learn about fuel trims myself so I can't be of much help. I always send a log file to Justin and ask for help.

 

[swathdiver]

Finally got the correct adapter so the Tech2 can connect to my laptop and interact with the TIS2000 software. Here is the same run as above with all the data recorded available as viewed from the TIS2000 software:

No broken exhaust bolts that I know of. All the heads of the bolts for the exhaust manifolds are in place and the six studs and nuts connecting the y-pipe are good as well. I would like to run my hands around the Y-pipe connection to just triple check for myself, everyone else who's been down there and done it says no leaks.

 

[Rocket Man]

Finally got the correct adapter so the Tech2 can connect to my laptop and interact with the TIS2000 software. Here is the same run as above with all the data recorded available as viewed from the TIS2000 software:

No broken exhaust bolts that I know of. All the heads of the bolts for the exhaust manifolds are in place and the six studs and nuts connecting the y-pipe are good as well. I would like to run my hands around the Y-pipe connection to just triple check for myself, everyone else who's been down there and done it says no leaks.

Did you set up a laptop with Windows XP so you can use the TIS2000? I can't load it on mine.

 

[swathdiver]

Did you set up a laptop with Windows XP so you can use the TIS2000? I can't load it on mine.

We have an old HP laptop (DV8000) that I bought new for my wife back in 2006. Still works and a year or so ago I was forced to put Windows 7 on it. Tried to also put it on my PC, Windows 10, but that didn't work. Laptop did not have serial port so I bought this: https://www.amazon.com/gp/product/B0000VYJRY/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 which allows the Tech2 to talk to the laptop. Plug and play, just had to change the com port in the TIS2000 software.

 

[Rocket Man]

We have an old HP laptop (DV8000) that I bought new for my wife back in 2006. Still works and a year or so ago I was forced to put Windows 7 on it. Tried to also put it on my PC, Windows 10, but that didn't work. Laptop did not have serial port so I bought this: https://www.amazon.com/gp/product/B0000VYJRY/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 which allows the Tech2 to talk to the laptop. Plug and play, just had to change the com port in the TIS2000 software.

I can't get setup to work so I think my installation disc is bad. It just hangs both my computers up; the desktop which has Win 7 64 bit and my laptop with Win 7 32 bit.

 

[swathdiver]

While I cannot remember any details, it did take some fussing for it to install on the laptop.

 

[Teeroy78]

Ok, the new Magnaflow Y-Pipe is installed (new cats) and fuel trims were reset and engine was burning 93 octane fuel. Mileage still poor, no misfires, runs great. What does the data suggest?

Sorry James, I don’t know what the data mean yet. However that sure sounds nice!