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Wandering afr

wetwea33

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#41
The map sensor wire is an input, feeding information to the fuel controller. The controller should not be pulling any power on that wire.

Sound like they may have just had a poor connection on the map sensor signal wire. This wire is critical to fueling the engine appropriately.
I understand this but I'm saying in the instance that the power is cut from the 10v (pulling the fuse to switch fuels) and the rest of the system is still hooked up the box will try to pull power from the 5v input and can mess with the map sensor voltage. My tuner let me know as I was interested in wiring in a switch to switch between fuels and said he's had people that have had issues with this.

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OP
PunkST

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Thread Starter #42
I can watch it on my way home. Eveything seems to be tight again. I did find a couple loose clamps when i did the starter.
 


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#43
I understand this but I'm saying in the instance that the power is cut from the 10v (pulling the fuse to switch fuels) and the rest of the system is still hooked up the box will try to pull power from the 5v input and can mess with the map sensor voltage. My tuner let me know as I was interested in wiring in a switch to switch between fuels and said he's had people that have had issues with this.

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This is interesting, and would be a poor design. Why not just switch the ground then? Lol.
 


wetwea33

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#48
Also to add, I am working on something that will allow the fuel controller to see more boost and add more fuel. Ie; one fuel map and done.

More details to follow.
I originally wanted to just wire the switch into the ground but no body seemed to be doing it and I couldint get a clear answer as to why. It is a poor design. I didnt think this was possible with aic1. Is there some way to get it to go off Lamda instead of afr?

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OP
PunkST

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Thread Starter #49
Have you thoroughly checked for leaks?
Watch Comm. EQ Ratio, and see if it also changes with the actual AFR.
Watched the eq tonight and it stayed dead on 14.70 when the actual afr started wandering like it does. Car was at 140 degrees coolant temp and it wandered till almost 160 degrees. Past that the actual afr went back to " normal"
 


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#50
Watched the eq tonight and it stayed dead on 14.70 when the actual afr started wandering like it does. Car was at 140 degrees coolant temp and it wandered till almost 160 degrees. Past that the actual afr went back to " normal"
Wait, so this issue is only present before the engine is fully warmed up?
 


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PunkST

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Thread Starter #51
Maybe. Once warm the car stays around 14.70-14.41 ish. Idk if thats too much of a variance. It can be a bit tough to gauge steady cruise witj an even pedal load given the roads around here being trash and bumpy. But the larger range does only seem to noticably happen when its almost warmed up.
 


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#52
I actually get the same exact phenomenon. I watched afr today, and even after full warm, it was wandering between 13.5-15.5 back and forth. Commanded stayed on 14.7 the whole time. But after a few minutes it cleared up and didn't happen again.
 


TyphoonFiST

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#53
Possibly due to winter Time formulated Gas? Maybe? Just throwing it out there.

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#54
Possibly due to winter Time formulated Gas? Maybe? Just throwing it out there.

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Quite possible. Or may be related to ethanol content in some fuels. I honestly don't think it's anything to worry about though. +/-1 point isn't huge at light loads.
 


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PunkST

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Thread Starter #55
I wonder if the car is testing short term trims for the fuel?
 


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PunkST

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Thread Starter #57
Hmmm. Let me take a look at my trims tonight. ( watch my car be all weird... Lol)
 


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PunkST

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Thread Starter #58
Stft was at zero while the afr did the wander.
 


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#59
What about at idle?
If your commanded was at 14.7 and actual was wandering, then STFT should have also been wandering in that same manner as afr. But when it hits and settles to 14.7, it should be close to zero STFT.
 


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PunkST

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Thread Starter #60
Didnt get a chance to look at it at idle once it was warm. My drive is all country roads. I can check it today.
 


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