So my car has been running great since getting it tuned this summer (above 80f) and now temps here in Portland have dropped to 30 degrees. That being said my car has begun to run like sh*t doesn't want to turn over easy at all takes multiple attempts and now sputters or just runs rough in the low RPM's. Could this be that when my car was tuned they didn't do any adjustments for cold weather? Or does this sound like something else?

Thanks in advance any info would be greatly appreciated.

Setup:
AEM: 1052
Fuel: E85
Supercharger: Vortech V2
Injectors: I.D 1000's
Exhaust: T1R 70R with test pipe

 

With a temp swing that large, there is a significant change in air density, so without some form of programmed 02 feedback to keep your afr on target, you will be running a lot leaner right now, which could explain your poor idle and partial throttle. I would contact your tuner and mention your issue and possible culprit.

 

E85 will be hard to start the colder the weather gets. There is a reason some gas stations switch to E70 so starting will be easier. It's running rough probably due to fuel and temp issues. What does car run like when fully warm? What are your afr's at cruising and idle?

 

Exactly, what's it run like when warmed up? Starting and after-start fueling is where E85 takes work when cold.

 

can you possibly get another tune for cold weather?

 

Thanks for the reply's. I have noticed it get slightly better as the car warms up but again we are dealing with an extreme weather change and my partial throttle still feels realy shitty at times. I have noticed my idle AFR's went from 14.5-15-6ish to upwards of 16.6 to high 17's even 18 flat lining my Aem guage. I have contacted my tuner English Racing and will be dropped the car off in the next few days. I was also wondering if a sensor may have went out??

 

There is no reason why you would need two tunes for cooler weather - the AEM has intake and coolant temperature compensation tables which allow the ECU to compensate for fueling requirements at varying temperatures. However, it is difficult to fine tune these tables unless you are tuning in the specific environmental conditions you are experiencing now. This is the reason why a tune done in the summer will result in poor starting and idling performance in the winter (or in reverse). Your tuner should be able to make changes to the starting and warm up enrichment tables to make both starting and warm up better.

That being said, there are two major considerations that will effect his ability to do this: 1) winter blend E85 can vary 15% or more in ethanol content compared to a summer blend. The solution for this is a fuel compensation sensor (like this one) - unfortunately, this requires a Series 2 AEM EMS. Your ECU is unfortunately not capable of FlexFuel tuning. This is a major reason we do not recommend using the Series 1 AEM EMS for E85 (in addition, engine reliability is in question if ethanol content changes so dramatically). The second issue is that due to the volumetric requirements between gasoline and ethanol (ethanol requires roughly 33% more volume), fine tuning very low pulse width operation (starting, idling, etc) will be more challenging.

 

Agreed, however, any tuner who has done a few E85 tunes can ballpark the cold weather stuff pretty easily. Once winter comes, fine tuning should make it spot on.




He's got the opposite problem as this would result in a rich condition by itself (or trims correcting a rich condition).

 

Thanks again for everyone's support and must say I have been purchasing from SoS for this build and always super helpful on the phone and receive parts very quickly. Nice to see them participate in these forums. So with it sputtering in the lower RPM's/partial throttle probably not a sensor and more just needing some tweaks to my tune?

 

Yes, this is the most likely cause of the degraded driveability, especially if it is temperature related. Temperature sensors rarely go bad (as they are not a moving mechanical device). However it it should be and would be easy to do a quick scan of all sensors that are a a part of fuel calculations to verify everything is operational. Note that this is not something to be upset with your tuner about - even very experienced tuners will not be able to tune exactly for environmental conditions that are drastically different than the environment that the car was tuned in. Tuners should educate customers that a repeat visit when the season changes should be expected and is normal. Thanks for the feedback, we appreciate it!