check engine light

[yaajclan]

Anyone with a flex fuel yukon having problem with check engine light. After filling up my tank with E85, my check engine light came on as well as error codes for the traction control and the stabilatrack. Now the car keeps jerking when going into 2nd gear. I took the yukon back to the dealer and they told me that there is a wrong mixture of fuel in my tank. I have not put regular unleaded in the car for a good 6 months, but the tech guy keeps telling me that it is reading a wrong fuel mixture and that is causing the computer to throw out error codes. Is anyone else having problems?

 

[PaulC]

As you consume the current tank of fuel, refuel with unleaded regular and dilute the E85, see if that eliminates the problem. Given ethanol's affinity for water, I would also wonder if water-contaminated ethanol may be the source of your problem.

 

[yaajclan]

Thanks for the input. I'll try that out. I asked the tech why would there be a wrong mixture, since the yukon is a flex fuel it should be able to take both no matter what. He told me that they don't mix well. If you are running regular, you should stick to it until it's time to refill and vise versa for E85. It still doesn't make any sense to me. Just wondering if anyone else is having problems.

 

[Poe1983]

This is a problem I would expect since these are some of the first flex-fuel engines that are made. I wouldn't expect these trucks to be problem free when it comes to this issue. Really, compare what you're paying for ethanol to 87 octane. I don't know where 87 stands in your state but here in So Cal it's the cheapest and works great in my Hoe. Crunch a couple of numbers and see what you're really going to save in the long run and ask yourself if it's worth it. I agree with PaulC. I'm assuming that the ethanol you're putting in might be contaminated.

 

[PaulC]

Thanks for the input. I'll try that out. I asked the tech why would there be a wrong mixture, since the yukon is a flex fuel it should be able to take both no matter what. He told me that they don't mix well. If you are running regular, you should stick to it until it's time to refill and vise versa for E85. It still doesn't make any sense to me. Just wondering if anyone else is having problems.

I have 21,000 miles on my '07 and have filled up with E85 just once, causing a mix of 1/3 regular unleaded / 2/3 E85. I then drove up long highway hills at 80 MPH for an extended period of time. Not one hiccup, not one indicator light.

As E85 is a mix of regular unleaded and ethanol, and the inclusion of more unleaded in the tank essentially dilutes the ethanol percentage, making it E60, E50, E30, etc., I'm not quite buying your tech's advice.