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sprinkles08, ASE Certified Technician
Category: Mercedes
Satisfied Customers: 22399
Experience:  ASE Master and Advanced level certified. Factory trained with 15 years dealership experience
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It quit on me on the way home. Had to keep full pedal all

Customer Question

It quit on me on the way home. Had to keep full pedal all the way . Had to gear down to keep up speed and to keep running sometimes. When I had to stop it would not even try to start. Had been hard to restart when warm for sometime. Have replaced fuel pump, tasted for fuel delivery through the fuel rail and injectors which is good. Has spark from the plugs.
JA: Have you ever replaced the fuel pump, or is this the original?
Customer: revisit original message
JA: What is the model/year of your Mercedes?
Customer: 2008 smart passion cabrio
JA: Are you fixing your Cabrio yourself? What have you tried so far?
Customer: yes. As in original message; replaced the fuel pump.Tested fuel delivery through the fuel rail and injectors and tested spark . All that is good.
JA: Anything else you want the mechanic to know before I connect you?
Customer: don't know of anything else
Submitted: 6 months ago.
Category: Mercedes
Expert:  sprinkles08 replied 6 months ago.

Hello and welcome to JustAnswer!

There are quite a few things that can cause a loss of power and no start condition. If it actually does have ample fuel pressure and normal spark then fuel quality or an exhaust restriction are most suspect.

You checked spark on every cylinder? What was the color and how large of a gap would it jump?

The first step in diagnosing the problem was to use a scan tool to check for fault codes. Did you check for codes?

Customer: replied 6 months ago.
I finally got a read out of the codes:
PO301 - cylinder 1 misfire, P2178 - system too rich off idle, PO447 - evaporative emission system vent control circuit open,
??? - evaporative emission system pressure switch high, PO451 - EES pressure sensor switch range/performance ?
Customer: replied 6 months ago.
Is there a $26 charge each trime we communicate on the same issue ?
Expert:  sprinkles08 replied 6 months ago.

You aren't charged per reply if that's what you were wondering.

Did you take a fuel sample?

What is the condition of the spark plugs?

Customer: replied 6 months ago.
The fuel is 93 octane as required. The spark plugs are new.
Customer: replied 6 months ago.
I tested spark also but only on 1 cylinder. It was yellowish and jumped about an inch gap from above the fuel rail.
Expert:  sprinkles08 replied 6 months ago.

What was the condition of the spark plugs when removed?

Have you taken a fuel sample?

Customer: replied 6 months ago.
Plugs were clean only been run maybe 50 miles. What am i to sample about the fuel. There is no water if that is the concern
Customer: replied 6 months ago.
Also removed the fuel rail and primed. It did not fire or try to crank. Also removed #1 cylinder plug and shot starting fluid with the same results.
Expert:  sprinkles08 replied 6 months ago.

It doesn't run on starting fluid?

Customer: replied 6 months ago.
I know that
Customer: replied 6 months ago.
What else can you tell me about the codes
Expert:  sprinkles08 replied 6 months ago.
If it doesn't run on starting fluid but has spark then you have an engine mechanical problem or an exhaust restriction.
Customer: replied 5 months ago.
what would be the exhaust restriction remedy ? I have not been able to see how to do anything with the exhaust system.
Expert:  sprinkles08 replied 5 months ago.

If the catalytic converter is restricted it will need to be replaced.