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OnlineHelp, Mechanic
Category: Car
Satisfied Customers: 3423
Experience:  Mechanic
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low yesterday and the engine warning light came..petrol..fault light

Customer Question

2004 1.8 Auto, have the car 6 months, fuel was low yesterday and the engine warning light came on just before I got to the petrol station. Filled the tank and hoped the light would not come back on, but it did. I was getting about 30 mpg but since the fault light the car is reading 40 mpg. Has dirt/water affected a sensor and should I be worried?
Submitted: 9 years ago via
Category: Car
Expert:  OnlineHelp replied 9 years ago.
You will need to check your fuel pressure. It sounds like you may have clogged the filter/line of the fuel system causing less fuel to reach your engine. You have to realize that all the residue that is in the tank is floating on the top, so when you run low that is what the pump starts pumping. It maybe just as small as the filter, however it maybe even the fuel pump itself. A fuel pressure test will tell you where you are standing.
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Customer: replied 9 years ago.
Thanks, XXXXX XXXXX car seems to be performing well. There are no flats or problems with acceleration. Fuel economy seems to have improved but I have travelled less than 20 miles so it is hard to judge at this moment. While I may have sucked up "bad quality fuel", I don’t think the engine is been starved of petrol as performance seems regular. Is there a sensor on the fuel line or could an oxygen sensor have been affected by dirty fuel? I know, if I go to my local Nissan garage they will tell me that a sensor is faulty and it will cost €300 plus to replace. (have the t-shirt from previous car). What’s the likelihood of the light going off after a few days driving?
I will accept after next reply
Expert:  OnlineHelp replied 9 years ago.
It could very well be your oxygen sensor picking up the bad gas that was being burnt. Here is what you can do, disconnect the battery for 5min and then reconnect it. The will reset the ECU and the light will turn off. Drive it and see if the light comes on, if it does i would go and have a OBDII diagnostic done on it. This would show what sensor has gone bad (if it is bad).
Customer: replied 9 years ago.
Hi thanks for that information. I will try it later today. Is there any point in trying a fuel additive/engine cleaner?
Customer: replied 9 years ago.
Thanks again
Expert:  OnlineHelp replied 9 years ago.
Yes, there is a point to it. Seafoam is a very good fuel cleaner and it works. You can also run a motor flush to clean out the passages.