Author Topic: Idle and A/F began wild oscillations  (Read 4020 times)

Offline smurfinator

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Idle and A/F began wild oscillations
« on: February 06, 2017, 02:17:32 pm »
Had gotten the car pretty well tuned.  Was fully warmed up for some time and idle suddenly began wildly oscillating and A/F gauge swings from .8 to 1.4.  Had not changed any parameters at all, just driving around the block getting the air out of the power steering.  Is this indicative of a mechanical failure somewhere, such as vacuum leak?  (looked, cannot find any).  Or what?

closed loop is off.  Idle timing control is off.

log file.  IU dunoo... :o

http://www.vems.hu/files/smurfinator/v3.3_u009651-2017.02.05-17.02.48.vemslog

config:
http://www.vems.hu/files/smurfinator/v3.3_u009651-A-2017.02.04-12.49.54.vemscfg


Thanks!
« Last Edit: February 06, 2017, 02:21:40 pm by smurfinator »
Audi ABZ 4.2 V8 in 1993 90 quattro
TTV 60-2 flywheel and cam sync
firmware: 1.2.20

Smurf blue (BMW Laguna Seca), hence the name!

Offline Sprocket

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Re: Idle and A/F began wild oscillations
« Reply #1 on: February 06, 2017, 03:13:18 pm »
I see TPS increase at the oscillations........... is this a manual input or some sort of throttle kicker motor?, or I see Aplha-N load compensation is enabled in idle settings which could cause this.


Use the tools menu

lock ignition value. Does it improve? no, then its not ignition causing the problem

Lock IAC value. Does it improve? no, then its not IAC causing the problem

Offline smurfinator

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Re: Idle and A/F began wild oscillations
« Reply #2 on: February 06, 2017, 06:06:13 pm »
Throttle blips are me to induce oscillation, although it does it anyway.  I think this is the wrong config because it doesn't have the above parameters disabled, but the ECU in the car does.  I will check that alpha N and lock value tests - thanks!




I see TPS increase at the oscillations........... is this a manual input or some sort of throttle kicker motor?, or I see Aplha-N load compensation is enabled in idle settings which could cause this.


Use the tools menu

lock ignition value. Does it improve? no, then its not ignition causing the problem

Lock IAC value. Does it improve? no, then its not IAC causing the problem
Audi ABZ 4.2 V8 in 1993 90 quattro
TTV 60-2 flywheel and cam sync
firmware: 1.2.20

Smurf blue (BMW Laguna Seca), hence the name!

Offline wersch

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Re: Idle and A/F began wild oscillations
« Reply #3 on: February 06, 2017, 06:50:13 pm »
The engine is running really rich in som areas, seems that the engine needs more adjustment?
Running lambda 0.8 with no load is way to rich.
You might also wanna try adjusting the ve table so it doesnt run leaner than 0.95 and see if the oscillations disapear.

Offline smurfinator

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Re: Idle and A/F began wild oscillations
« Reply #4 on: February 06, 2017, 06:57:36 pm »
It seems like the alpha N thing was the problem :)  Thanks!!

I had been messing with the VE table to try and stop the oscillation so it's rich in places.  I used a config tuned by a hero member/installer here (I forget who) on another member's car at the map does not work for mine at all - way off in places.  I am at 7000 feet altitude, however.  Anyway, I had inherited that 10% alpha N setting from him and I didn't know what it was for.  Now that it's stable i can get back to tuning... things like acceleration enrichment are not matching well, either.   And now I just discovered my brand new coolant tank is cracked (&^%$#@!@#$%%^&^&***^!!!!!!!).  So car is down for the count again.  This is my third tanks @50$$.  So angry with this car.
Audi ABZ 4.2 V8 in 1993 90 quattro
TTV 60-2 flywheel and cam sync
firmware: 1.2.20

Smurf blue (BMW Laguna Seca), hence the name!