From one of the "Flexfuel Kit" manufacturers websites " Ethanol is less flammable than gasoline, so the ignition problems can occur more easily when using ethanol. In some vehicles, a slight stumbling during the first 5 minutes of driving is normal in cold weather conditions. If the spark plugs or ignition coils are defective or have reached full lifetime, small stumbling can occur with a cold engine. If the engine is warm there should not be any stumbling with gasoline or with ethanol. " I'd get rid of the "kit" and go back to normal gasoline and see what happens.
Rough idle when cold
- Thread starter OM605
- Start date
Well, my car is back on the road ! Turns out it was a combination of 2 dirty injectors and a bad MAF sensor, everything is fixed and the car starts perfectly when cold on E85 and gas. The flexfuel conversion kit has an ethanol sensor similar to those on GM flexfuel cars sold in the US. Fuel trims are always around 0 so the kit does what it's supposed to.
While i'm at it, it seems like there's a lot of misconception about ethanol around here. It's becoming very popular in France for the last 10 years and it does not cause any issues if the vehicle is properly converted. Used it for almost 400 000 kms on various vehicles (mainly 90s mercs) without any issues. It does not do any harm to the fuel supply system if the car is made to handle E10.
However it can harm fuel lines not made to handle ethanol in older vehicles and just like E10, not really working well with carbs. The biggest source of disasters is when a vehicle is not properly converted and running lean. I've seen holes in pistons, burt valves and melted cats because of people switching to E85 without any modification or at least without a scan tool and a proper understanding of how a gasoline engine's electronic injection system works and driving with a CEL.
Thanks to E85, my fuel bill is only 150€ each month at the most, it would be 400€ on gas. E85 is 0.60€/L while regular unleaded is 1.50€/L. Imagine paying $7 or $8 dollar per gallon. You would be tempted to do something drastic. It also makes the car more pleasant to drive and a bit more silent. Oil stays clear longer and no more carbon build up.
PS : Without a conversion kit, ECUs are usually not able to compensate enough. Very few cars can run 100% E85 stock, fuel trims will be maxed out far before that so a CEL will appear and the car will run lean. Some people do mix gas and E85 50/50 or other ratios rather than installing a conversion kit. Fuel filter has to be replaced one or two times after a conversion because ethanol will flush out all of the gunk really quickly. This is important on an older car.
While i'm at it, it seems like there's a lot of misconception about ethanol around here. It's becoming very popular in France for the last 10 years and it does not cause any issues if the vehicle is properly converted. Used it for almost 400 000 kms on various vehicles (mainly 90s mercs) without any issues. It does not do any harm to the fuel supply system if the car is made to handle E10.
However it can harm fuel lines not made to handle ethanol in older vehicles and just like E10, not really working well with carbs. The biggest source of disasters is when a vehicle is not properly converted and running lean. I've seen holes in pistons, burt valves and melted cats because of people switching to E85 without any modification or at least without a scan tool and a proper understanding of how a gasoline engine's electronic injection system works and driving with a CEL.
Thanks to E85, my fuel bill is only 150€ each month at the most, it would be 400€ on gas. E85 is 0.60€/L while regular unleaded is 1.50€/L. Imagine paying $7 or $8 dollar per gallon. You would be tempted to do something drastic. It also makes the car more pleasant to drive and a bit more silent. Oil stays clear longer and no more carbon build up.
PS : Without a conversion kit, ECUs are usually not able to compensate enough. Very few cars can run 100% E85 stock, fuel trims will be maxed out far before that so a CEL will appear and the car will run lean. Some people do mix gas and E85 50/50 or other ratios rather than installing a conversion kit. Fuel filter has to be replaced one or two times after a conversion because ethanol will flush out all of the gunk really quickly. This is important on an older car.
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I think I need to learn more about your conversion kit. Do you have a link?
If it’s got a sensor, I’m surprised. That’s a level of sophistication I wouldn’t have suspected. You need bigger injectors, too, as the required flow rate of E85 is about 70% MORE than your stock E10/gasoline injectors. How does the kit and sensor interface with your ECU?
If it’s got a sensor, I’m surprised. That’s a level of sophistication I wouldn’t have suspected. You need bigger injectors, too, as the required flow rate of E85 is about 70% MORE than your stock E10/gasoline injectors. How does the kit and sensor interface with your ECU?
The conversion kit is made by finnish company called Eflexfuel. E85 is very popular in Finland and Sweden too since the early 00s. The kit works by increasing the injectors opening time according to the signal sent by the ethanol sensor placed on the fuel line.
You can connect to it via a bluetooth app to check various data like real time injectors opening time, which is important since some cars don't have big enough injectors as well as real time ethanol content etc. In fact if the kit is working as it should no matter the ethanol content, the values in the ECU like fuel trims etc should be the same as a stock car.
About injectors : i can see in the app that my injectors never go above around 45% duty cycle under WOT at high rpm on E85 and maybe a bit less than 30% in the same situation when using gas. But Mercedes put the same big injectors on my little engine as they did on the way bigger models so i'm fine.
You can connect to it via a bluetooth app to check various data like real time injectors opening time, which is important since some cars don't have big enough injectors as well as real time ethanol content etc. In fact if the kit is working as it should no matter the ethanol content, the values in the ECU like fuel trims etc should be the same as a stock car.
About injectors : i can see in the app that my injectors never go above around 45% duty cycle under WOT at high rpm on E85 and maybe a bit less than 30% in the same situation when using gas. But Mercedes put the same big injectors on my little engine as they did on the way bigger models so i'm fine.
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Thank you. I appreciate it.
