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Matt, Engineer
Category: Mercedes
Satisfied Customers: 20378
Experience:  Mechanical Engineer with 23 years experience in the auto industry, 8 yrs in formula 1 engine testing
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JA: . How can we help? Customer: I suspect I have

Customer Question

JA: Hello. How can we help?
Customer: I suspect I have bought bad fuel. Being in Nigeria where there are few experts, very difficult to tell
JA: Sometimes things that you think will be really complicated end up being easy to fix with a Mercedes. The Mercedes Mechanic I'm going to connect you with knows all the tricks and shortcuts. Tell me a bit more about what's going on so he can help you best.
Customer: ok
JA: Are you hoping to fix this yourself?
Customer: ok let me tell you the sequence of events
JA: Great! What have you tried so far? Is there anything else the Mercedes Mechanic should be aware of about your Mercedes?
Customer: I had a half tank of Gasoline and went to the gas station to fill up. Bought about 50 litres of Gasoline
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Mercedes Mechanic about your situation and then connect you two.
Submitted: 6 months ago.
Category: Mercedes
Expert:  Matt replied 6 months ago.
hican you tell me what model , year and engine size this is please?also how many miles are on the car and when it was last serviced I'm assuming that you don't have any check engine lights on and this issue only started after you filled up?does the car have a lack of power?
Customer: replied 6 months ago.
I am writing you from Nigeria in Africa.
Vehicle is 2013 Mercedes Benz GL550. Car was last Serviced in January in Ottawa, Canada with approximately 44,000km.
Car was shipped to Nigeria and mileage is currently 45,000km.
I had a half tank of good fuel as Car was running smoothly, I then filled up with about 50litres of Gasoline. I used up 15 litres after filling up. This problem started after filling up the tank. I suspect bad fuel as that was the only thing added to the equation although I dont have a way of checking.
In more detail, while driving, the yellow check engine light came on. I stopped, checked the gas tank cap and closed again properly. Left car for about 1 hr and started again. the light disappeared and engine was running fine. Left Car parked for another 3 hrs and started again. Car was running fine and then drove for about 3kilometres and the check engine light came up again.
In terms of power, it feels the car is running on 7 cylinders instead of 8. I say this because, if you rev up the engine, it revs up pretty well but you will notice it not as sharp as it should be. When the engine is idle, it shakes as though its now running on 6 cylinders, meaning the issue is more pronounced.
Please let me know what you think. Also, if we were to drain the tank, I will need your help to locate the tank and a quick summary of how to drain it. As you may be aware, we do not have such great hands on experts in this part of the world and I will have to supervise anything done on the car.
Expert:  Matt replied 6 months ago.
I'd agree that as the problem started directly after filling up then yes bad fuel is quite likely there's no drain tap on the tank and you may be able to get some out through the filler neck by siphoning it out by there's an anti-siphon valve in the filler neck that makes this difficult the best way is to remove the fuel line in the engine bay where its plumbed to the injector rail and then extend the pipe with some regular petrol hose to run into a vessel then locate the fuel pump relay in the engine bay fusebox and remove it, and use a jumper wire to bridge the power terminals so the pump runs all the time
Expert:  Matt replied 6 months ago.
the pump will then run continuously and empty the tank for you
Customer: replied 6 months ago.
Hi Matt,
Thanks for your response. I will agree that the procedure you suggested is the easiest. However, in this part of the country, I do not have the required expertise to locate the actual fuse and jumper the terminals safely without frying anything.
Please refer to the attached pictures of the fusebox in the engine bay perhaps pointing out which fuse and a detailed step by step procedure of what to do.
Alternatively as a second option, can we locate the fuel tank and directly drain the fuel. I understand this may be more tedious to do. Where is the fuel tank located in the car?
I recorded a video of the dash while running the engine to give more insight. I await your response. Thanks
Expert:  Matt replied 6 months ago.
Hello I've looked into this some more and the the fuel pump relay was replaced by a separate 'module' so no relay to jump this being the case you can manually run the pump by lifting the rear seat cushion to reveal the blanking plate and then remove that to reveal the fuel pump and then run 12V to the pump terminal