AEM Pro's! Strange leaning out issue ?

[slowgsr]

So, the car is a 6 bolt. 2.0L

FIC 2150s
Q45 TB
S372
AEM IAT/3.5bar

Im having a strange issue. I was at the track doing some pulls and the car was running good, I was dialing in boost and AFR's. So after a pull, I head back to the pits and notice my idle is slightly leaner, and running kind of 'lumpy'.

The AFR at idle is suddently 14.5-15.0. Thats too lean for my 2150s on gas, they idle perfectly around 13.0-13.5 which is where I always have my idle.

I can't figure it out, its lean all over the map, and where the pulsewidth values are lower, it runs 'lumpy'.

So I drive back home from the track (45min), and its gradually getting worse, by the time im almost home, afr idle is 17.0:1, and the car barley wants to idle.

I've checked everything mechanically as far as fuel system goes, and its not an ignition problem.

So, I did a quick log. I start the car.. starts up pefectly fine, idles around 13.0, then it sits and idles fine, and as soon as I 'blip' the throttle, the RPM's come back down and my idle is suddently 14.5-15.0. Then the car runs rough. It dosen't return to 13.0, it just slowly gets leaner and leaner over time.

The log shows the PW at idle 13.0 when I first start the car to be around 1470-1505, then after I blip the throttle and the idle comes back down and the afr's sit 14.5-15.0 my PW is suddenly 1415-1435.

Because of this pulsewidth values changing its leading to believe theres some sort of comp table that got corrupted, or suddenly decided to kick in for whatever reason? Its never done this. I tried a .cal from a few days prior and same issue.

Im thinking the root cause is in my .cal and not an issue with the car.

It was strange, when I was inspecting under the hood, I noticed a couple of the wires that go into the injector pigtails were 'loose' as In I tugged and they came out, meaning from factory (FIC) they were not clipped into the connector properly. The issue is not as bad as a dead cylinder, or an injector not firing. There all firing, the loose wires were on injectors 1 and 4. I just removed the plug and properly clipped in the pin.

If someone could give me suggestions, or care to take a look at my .cal or log, it would be awesome. This is such a pita. I finally started dialing in higher boost levels.

 

[turboglenn]

one problem i've seen others have with the AEM is the "auto-tune" ressetting and turning it's elf on and if the calibration from the wideband isn't correct it wil go super lean instead of super rich and the more you drive the more it adjusts the AFR's based on closed loop feedback from the wideband, so check that the auto tune is turned off

some more info about your setup or host your calibration file up some here that i can look it over and i'll try adn give you more help. Teh auto tune usually tends to re-set when the battery is disconnected or goes dead

 

[slowgsr]

You must be logged in to view this image or video.

As you can see the top is AFR, see how once I blip the throttle it changes fairly drastically? RPM is the same, and theres no other major changes.

 

[92tsiawdguy]

That auto tune shit is a joke. It could also be that your wideband sensor is going bad or needs an open air recalibration.

 

[slowgsr]

My 02 sensor is brand new, I replace them yearly. Its a AEM unit, and also guys, I do have the 02 feedback adjustment turned ON. I will turn it off, and see if I still have the same problem.

Guys, thanks a lot. Im thankful for the fast feedback.

Last x2 years, I never used the 02 feedback, this year for some reason I decided I might give it a shot based on my friend had good results with the autotune features in MS on his turbo neon.

Glenn, I cannot upload my .cal file here. It says invalid file, its a AEM EMS cal. I can quickly email you the file if you can provide me with your email, you can PM me your email too.

 

[turboglenn]

just diable the auto tune, keep your wideband hooked up and tune it yourself and it will stay

but if you disconnect the battery for some reason they will tend to turn the auto tuneback on (seen it on 3 AEM powered cars i've worked on now) and if the calibration of the wideband input (the numbers you input to the EMS unit for each AFR) is not re-done then it reads a voltage it has no idea what it represents and even thoughg the stock or base auto tune map is for like freaking 7.8:1 or some crap it just won't know what the volatge mens and just start changing the tune

do you have a backup of your previous cal file before it went lean? if so open and compare the numbers in the cells for the fueling and see if the ECU is changing it on it's own

just always make sure annytime you hookup the laptop, kill or disconnect a battery that you double check those 2 things./

 

[diambo4life]

Battery voltage. Check that. Had a similar issue on an AEM EVO 8 I was tuning. It was on 1600cc's and when the voltage would drop significantly especially at idle, it would behave that way. His car was using a hybrid boost comp map though with no closed loop feedback. Just an idea. .

 

[slowgsr]

Thanks.

Batt voltage is good, logs show a steady 13.0. I will disable the auto tune 02 feedback tonight after work and load up a older .cal from before when I disconnected the battery (wednesday). I will then make sure the voltage afr table is correct.



Seems the 02 feedback enable was the problem im thinking. I turned it off, and PW no longer drops and says where it should. I let the car fully warm up and no issues. Im keeping my fingers crossed that was the problem.

It was the worste at idle, and now its back to how it always was, so im happy.

 

[slowgsr]

Figured out the problem!!!

Special thanks goes out to TONY1 from T1Race Home

The problem turned out being the combination of my FIC2150s and my Profuels mark 5 fuel, It contains mtbe and was causing the flow to decrease as the face of the valve swells.

Awesome!!! The only down side is what to do with all this extra fuel I have thats $4/L. Too bad no E85 up here . Ill have to switch to C16.

 

[alex1090]

If you have the pump to support it and injectors that big, just switch to Q16 rather than C16. Lot more power to be made with Q

 

[C_Keagy]

Cant run Q on the Fic 2150's