''Scratchy'' engine, lumpy idle
Discussion
My friend recently ran dry his '95 fiat cinquecento (petrol). He's now noticed a lumpy idle when it warms up and the engine sounds 'scratchy' at the lower rev range. It is also a bit jerky when he accelerates in 2nd gear (possibly not only 2nd).
My uneducated guess is it is an issue with the fuel injectors from when he ran it dry, but i have no idea really, that just sounds like a plausible explanation. Does anyone know what the real problem is?
My uneducated guess is it is an issue with the fuel injectors from when he ran it dry, but i have no idea really, that just sounds like a plausible explanation. Does anyone know what the real problem is?
dan19evans said:
if he ra it dry of petrol, theres a good chance its sucked up all the crap out the bottom of the fuel tank, which could have blocked up the fuel filter or the injectors
Where exactly is the pickup point of a fuel tank? At the bottom maybe? I thought the same untill the pistonhead possie corrected me.
GingerWizard said:
dan19evans said:
if he ra it dry of petrol, theres a good chance its sucked up all the crap out the bottom of the fuel tank, which could have blocked up the fuel filter or the injectors
Where exactly is the pickup point of a fuel tank? At the bottom maybe? I thought the same untill the pistonhead possie corrected me.
Ash1 said:
Yeah thats a myth. The petrol tank is known to be the cleanest part of any car because of the cleaning properties of petrol, and due to the fact that there is no crap in it to begin with because its filtered so much before it reaches the car.
That rather depends on whether your fuel tank is metal and rusting from the inside out...Edited by itiejim on Sunday 13th June 22:40
Ash1 said:
Yeah thats a myth. The petrol tank is known to be the cleanest part of any car because of the cleaning properties of petrol, and due to the fact that there is no crap in it to begin with because its filtered so much before it reaches the car.
Clearly you've not cleaned out many old petrol tanks. They can get a lot of crap in them, especially old metal tanks. Fuel has water in it, and moisture can also condense out of the air in a partially full tank, both of which will sink to the *bottom* of the tank.GingerWizard said:
dan19evans said:
if he ra it dry of petrol, theres a good chance its sucked up all the crap out the bottom of the fuel tank, which could have blocked up the fuel filter or the injectors
Where exactly is the pickup point of a fuel tank? At the bottom maybe?This is one of those things that's now regularly touted as an "urban legend" that actually has a basis in truth. That said most modern cars use plastic tanks so rust in the tank is not normally a problem these days.
Running the tank dry is a good way of damaging the injection pump, they rely on fuel passing through the motor to cool and lubricate it.
Edited by Mr2Mike on Tuesday 15th June 09:50
Mr2Mike said:
Ash1 said:
Yeah thats a myth. The petrol tank is known to be the cleanest part of any car because of the cleaning properties of petrol, and due to the fact that there is no crap in it to begin with because its filtered so much before it reaches the car.
Clearly you've not cleaned out many old petrol tanks. They can get a lot of crap in them, especially old metal tanks. Fuel has water in it, and moisture can also condense out of the air in a partially full tank, both of which will sink to the *bottom* of the tank.Ash1 said:
How much air is there inside? Surely its sealed and has a valve at the opening?
When it's empty it's full of air. When it's 1/2 full of petrol it's 1/2 full of air. If you just removed the petrol it would create such a low pressure that either the tank would collapse, or the fuel pump wouldn't be able to "pull" hard enough to get the fuel out.Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff