olebenz

Hello, working on a 2008 C300 3.0 Flex. Car had been sitting for a few weeks. Sunroof drains clogged up and damaged the CAN bus blocks on the floor. Those have all been replaced and they got the car running for a short time. Car ran great. Drove around for about 5 minutes no issues. Parked it and it would not idle anymore and started sputtering and stalled out. It hasn't ran since. Haven't scanned codes yet but will when a new scanner arrives. Old one quit. Car cranks over and sputters. Throttle input does nothing. Can hear the fuel pump and can smell fuel. Car has around 130,000 miles. Have a crankshaft sensor on order just cause. Anybody have any ideas. Obviously the code scanner will be needed. Figured I'd ask. Thanks in advance for all that reply.

cvx5832

Sounds like it's choking on bad gas. You sure about what's in the tank?

olebenz

Not exactly sure on the fuel age or quality. Only has a quarter tank. What's weird to me is it drove perfectly fine for 5 minutes then as soon as it was parked idling like trash and stalled. Not saying the gas isn't trash and what was in the lines was good

cvx5832

There's also phase separation from fuels with ethanol and age. "Age" dependent on humidity, ethanol % and temperature. If it is bad gas, not sure how to drain the lines, though.

olebenz

That is correct. Hmm. Might try some stabilizer and some fresh fuel and see what happens. The sputtering and stalling was awful and even sounded like a backfire through the intake making me think crank sensor.

JettaRed

iTrader: (1)

Flex Fuel cars have a fuel quality sensor. Since you were flood damaged, check this thread.

2014 C350 Fuel Quality Sensor (Flex Fuel Sensor) P0178 - Solved - MBWorld.org Forums

olebenz

Well put about five fresh gallons of fuel in it and it really wanted to run but never would. Just sputtering. Found barely any pressure at the rail. Looks like fuel pump isn't making enough pressure but is pumping. Ordered a new assembly. Also pulled a spark plug and it was very dark and looked worn out. Replaced them all with Bosch DP per OEM, same issue. Hopefully the new pump solves the pressure issue. I can hear the fuel pump but only barely. Its just so odd it ran fine for a short time. Perhaps it ran off of what was in the lines and then once the pressure was gone that was it. We shall see. I haven't checked that flex sensor yet after finding low pressure.

olebenz

Just became aware that they have a main fuel pump as well as a transfer pump/filter on the left side of the vehicle. I ordered the primary pump due to low pressure. But now I was wondering if the other needs to be replaced as well. Is it a common thing to replace the transfer/filter pump and if so, I'm having a rough time finding the correct part online. I'm going to assume that the car will run if the filter/transfer pump (left) has failed so long as the primary pump is working and vehicle has sufficient fuel?