Closed loop - poor fuel mileage

[earthling]

Its worth a quick once over of the entire exhaust. Any leak in the exhaust will throw off the O2 sensor. The primary impact of which is that the sensor would read the AFR as lean. (causing enrichment and poor mileage).

 

[THEPASMAN]

I’m my case it involved the AEM sensor. There was a bad batch of them that made it to market it took over a year to resolve with the vendor and about 800 miles on the sled some of those were with the sensor unplugged cuz I couldn’t handle looking at 14.5 on the screen. Sled runs super strong now so I don’t think there was any permanent damage. Tune went in in Jan22 and it was the following Jan that it was resolved. With lots of conversation in between The sensor never did quite and would function properly at times. It was very frustrating and impossible to dial in the clutching. I believe it was the module that was the problem not the sensor as I changed both to fix it. If it was a resent purchase I’d be on the vendor to make it right sooner than later.
Good luck

 

[justinator]

I believe u can only read boost on the hr meter with the stock guage? Need dash flash to get afr

If you have the flasher and the app you can select in the app if you want hr meter to read boost or afr. If you have dash flash you can monitor both at same time.

 

[Richard Hodgins]

Does the closed loop turn off and default to the tune when the O2 sensor takes a crap?
Can the O2 sensor just give false readings, and if so is there a possibility for damage if it leans things out when it’s already lean and reading false values

It should throw a code if the 02 is bad and then the tune will default to the base tune so MaxSpool 17 in my case. I dont think it could ever lean out totally.

 

[Richard Hodgins]

I’m my case it involved the AEM sensor. There was a bad batch of them that made it to market it took over a year to resolve with the vendor and about 800 miles on the sled some of those were with the sensor unplugged cuz I couldn’t handle looking at 14.5 on the screen. Sled runs super strong now so I don’t think there was any permanent damage. Tune went in in Jan22 and it was the following Jan that it was resolved. With lots of conversation in between The sensor never did quite and would function properly at times. It was very frustrating and impossible to dial in the clutching. I believe it was the module that was the problem not the sensor as I changed both to fix it. If it was a resent purchase I’d be on the vendor to make it right sooner than later.
Good luck

And you werent getting any codes? I'm wondering if that's what's happening, its a bad 02. I dont have the AEM module.

 

[THEPASMAN]

Mine showed running lean most of the time with no codes. If you unplug sensor it will revert back to original tune without CL. And I would think your fuel mileage will be back to normal. I’d either replace module or get dash flash to monitor afr

Other than that it would be a problem with the tune

Is this a new install ?

 

[THEPASMAN]

I believe it was a module issue as I swapped out o2 sensors with no change

 

[Doc Harley]

I believe AEM sells the module and some universal wiring relatively inexpensive, it would just need to be pinned correctly.

 

[THEPASMAN]

And you werent getting any codes? I'm wondering if that's what's happening, its a bad 02. I dont have the AEM module.

Just reread old posts from last winter there weee other guys having the the same issue with ECU Masters https://ty4stroke.com/forums/sidewinder-trail-talk.119/

 

[02ViperMody44]

Last year my O2 sensor went, on Hurricane tune, and it began running super rich. My mileage went way down. Lucky to get 10mpg. There were NO CODES present, but when looking at the afr reading on the factory gauge, the numbers were all over the board. Nothing steady. Replaced the o2 sensor and back in business.

 

[Crossfire12]

My mother always told me the more you monkey, the more you can.

 

[Doowithblue]

I was under the impression that if 02 sensor fails it defaults to 300 ss tune in which case mileage isnt really horrible?

 

[Doc Harley]

My mother always told me the more you monkey, the more you can.

I Incorporated The kiss principles
Keep. it. simple. stupid.
Works on everything in life.

 

[snowdust]

I was under the impression that if 02 sensor fails it defaults to 300 ss tune in which case mileage isnt really horrible?

If the sensor is not reading it will go back to the default tune. If the sensor is reading but not accurate, there would be no programmatic way the tune would know without another source to go off of.

 

[fxnytrortxkid]

Closed loop won’t work untill at or over 18mph, if sensor goes bad it will mess with reading, you unplug the sensor then it reverts to the stock maps.