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420A 10.0+ AFR reading

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Inkdlyfe

Proven Member
438
7
Feb 23, 2016
Summer feild, Florida
Lately my car been running really really Rich all of a sudden. Nothing has been changed about the car besides going back to 93 gas instead of E85, I dont see or hear any vacc leakes and the only check engine light I have now is for the ect sensor which was bad before this rich issue happen. Basically I can cruse at 14.5 range on the afr but the second i give it gas it goes to 11.5 then creeps to 10.0+ range and normally when I get under boost i see 12.5 but now if i calmly accelerate i see 12 range not even pushing it. I dont seem to have any boost leaks and exhaust leaks ether but not 100% sure. Also pulled all my plugs they all seem about the same ware ..
 
The ECU needs to know the engine coolant temp. If that is not working correctly the car may be stuck in warm-up mode. Also, these AFR readings are coming from a wideband o2?
 
Broken coolant temp sensor, and the ECU defaults to -40 degrees. It will be a ton of fuel it will try to add. I'm actually surprised you were able to get the car started and running with a broken coolant sensor. Most cars I've experienced will not want to stay running for more than a few seconds.

Also +1 to what Sjd6795 said, if you don't have a flex fuel sensor or any way to tune it back to 93 octane it will be rich as well.
 
The car was never tuned on e85. My buddy just said to run it so I did and it runs amazing on it but it was tuned on 93 . Never e85 . So no it was never changed tuned wise only put e85 and rode out so maybe the ECU got use to the e85 and I finally got the e85 outta the system maybe ? Ans yeah the sensor been broken for a month or more and I drive it about 50 miles a day
 
The ECU needs to know the engine coolant temp. If that is not working correctly the car may be stuck in warm-up mode. Also, these AFR readings are coming from a wideband o2?

Yes from the wide band o2 afr aem gauge
 
So even tho it was tuned on 93 should I go back to e8 . Could that be the reason for this ? I mean I filled up every day before work on e85 cuz it only took 20$ to fill up and never had any issues at all on e85 just got told I shouldnt run it w out 2 pumps in the tank? And w out a tune ? But it ran perfect on e85 w only a 255 pump and 93 tune
 
You can not simply just switch to E85. It doesn't matter if you have 1,2 or 5 fuel pumps. How many pumps you need will be determined by your fuel flow requirements. From your other threads I know your running a portfueler setup. You have no control over the factory EFI system. All you can do is add additional fuel to compensate for the extra airflow in boost.

My only guess as to why your car even ran with E85 is because the coolant temp sensor is broken.

Fix the parts of your car that are broken and report back.
 
Well I fixed the sensor... still acting up only thing that changed is my idle is alittle better.. still running rich
 
I'm going to look more into it today see if putting e85 changes anything
 
Anyone know where to get fic8 base map? Imma try and redo my fic8 I think it's in the aem, I put my fic6 in (has a bad internal map) and it dont run rich 10.0 under boost leans out cuz no load is being read. But it dont run rich like the 8 does.
 
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