Tonyrodz's Tahoe Build Thread

[HiHoeSilver]

The 1st scans were just at idle. Unfortunately I wasn't able to get pics of the fuel trims on the short ride today. I did see a high of 10 on the short term trims--I think on bank 1. Driver's side? Do you know how to reset the trims with the Tech 2? I'm guessing it would be under the "Special Functions" menu?

Close to 0 at idle, and +10% under load? You may have a fuel delivery problem, my friend.

 

[Tonyrodz]

Close to 0 at idle, and +10% under load? You may have a fuel delivery problem, my friend.

I gotta check the fuel pressure. Wouldn't it be on both banks then? Showing a problem just on bank 1. Pump is whining or making any funny noises.

 

[HiHoeSilver]

I gotta check the fuel pressure. Wouldn't it be on both banks then? Showing a problem just on bank 1. Pump is whining or making any funny noises.

Again, I might not have gone back far enough for all the deets. You wont get a rich/lean code until that long term hits +/-25, so its really only halfway there.

The pump would typically affect both banks similarly. Maybe a line/rail/injector problem? More data, more data!

 

[Scottydoggs]

this is kinda why i put a dual wide band in my camaro. with its big cam the long term fuel trims on both banks at idle are -14 -15. once moving they drop to -5 or lower. wb on both banks reads the AFR at 14.6 to 15.3 back and forth at idle, so its not really rich if your trusting the wb. figured it would be nice to see if one side was lean or rich being a boosted set up.

 

[iamdub]

Again, I might not have gone back far enough for all the deets. You wont get a rich code until that long term hits +/-25, so its really only halfway there.

The pump would typically affect both banks similarly. Maybe a line/rail/injector problem? More data, more data!

 

[Tonyrodz]

Tested the fuel press at the rail. Looked ok to me.
Key on, engine off.
After 5 mins.
At 2500 rpms.
At idle.

At 4000 rpms
Shut off and still holding pressure after 5 mins.

 

[Tonyrodz]

Random pics of the Tech 2 while it was running.

 

[Tonyrodz]

More random.

 

[Tonyrodz]

Tech 2 readings.

 

[Tonyrodz]

Sorry for the random pics, but hopefully there's info in here that might shed some light on my issue--I don't know how to interpret it.

 

[Fless]

Did you find the menu to reset the long term fuel trims? I would recommend that, but I'm not seeing anything amiss. It goes into closed loop and the short term fuel trims are dead on, well within the desired management window.

Only 1 misfire in 4 cycles of misfire data on a couple of cylinders, nothing to worry about. If you collect more cycles, do the misfire counts go up?

 

[Tonyrodz]

Did you find the menu to reset the long term fuel trims? I would recommend that, but I'm not seeing anything amiss. It goes into closed loop and the short term fuel trims are dead on, well within the desired management window.

Only 1 misfire in 4 cycles of misfire data on a couple of cylinders, nothing to worry about. If you collect more cycles, do the misfire counts go up?

No, they don't go up. I looked all over the menus to reset fuel trims but couldn't find it. Can they be reset on the NBS? Or is it just the NNBS?

 

[HiHoeSilver]

No, they don't go up. I looked all over the menus to reset fuel trims but couldn't find it. Can they be reset on the NBS? Or is it just the NNBS?

You can reset them. I don't have a tech 2, *hangs head in shame, but have had them reset on mine before.

 

[Fless]

I think the LTFTs reset if the battery is disconnected. Might have to touch the two battery CABLE ends together while it's disconnected.

 

[HiHoeSilver]

I'm with @Fless here. Reset them and then see what they do. The long terms adjust based on what the shorts are doing. Your shorts show no reason for the longs to have moved that far. Maybe just old data and we're barking up the wrong tree.

 

[Fless]

I'm with @Fless here. Reset them and then see what they do. The long terms adjust based on what the shorts are doing. Your shorts show no reason for the longs to have moved that far. Maybe just old data and we're barking up the wrong tree.

Woof woof.

 

[Tonyrodz]

Some vids of the Tech 2 while the Tahoe is running.

 

[HiHoeSilver]

I think the LTFTs reset if the battery is disconnected. Might have to touch the two battery CABLE ends together while it's disconnected.

Hmmm. Maybe that's true. Iirc, it didn't work for me and needed my buddy with a bidirectional tool (not T2) to do it.

 

[Fless]

To reset the long term fuel trims, connect the Tech 2 and enter your vehicle information, and go into the Powertrain menu. Of course you'll want to be in the Diagnostics menu.

> Special Functions
> Fuel System
> Fuel Trim Reset. It collects some data for a few seconds.
On the next screen the fuel trims are shown, and a soft menu item "Reset" at the bottom of the screen should appear. In order to select it, press the corresponding soft key (just below the screen) once -- or you might need to do it a second time -- and the LTFTs should reset to zero. (Since the engine is not running, the STFTs are static at 0.)

 

[HiHoeSilver]

To reset the long term fuel trims, connect the Tech 2 and enter your vehicle information, and go into the Powertrain menu.
> Special Functions
> Fuel System
> Fuel Trim Reset. It collects some data for a few seconds.
On the next screen the fuel trims are shown, and a soft menu item "Reset" at the bottom of the screen should appear. In order to select it, press the soft key (just below the screen) once -- or you might need to do it a second time -- and the LTFTs should reset to zero. (Since the engine is not running, the STFTs are static at 0.)


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