Running rich on fuel

Fri Sep 11, 2015 9:28 am

Hi,

Currently the car is running 60 miles on £30 fuel which is quite rich. Also there is a heavy smell of fuel from the exhaust when parking it in the garage. I have carried out the following and have had no success:

Car: e30 325i sport 1989 m20 engine

Replaced the following:

1. Blue coolant temp sensor
2. all spark plugs
3. distributor cap and rotar arm
4. Check the c191 loom - all ok

Is there anything else I can check please or replace??

Please advise

Fri Sep 11, 2015 9:48 am

Obvious thing is are you sure it's not just a simple leak? Have you stopped on the road with the engine running and carefully checked for drips and damp patches?
If the problem is with the fuelling, then your symptoms don't necessarily mean the engine is running rich. A weak mixture will also use excess fuel and make the exhaust smell of fuel, as will a complete cylinder which is receiving fuel but not igniting it.
Take out the spark plugs and examine the colour of the tips. Pics. would be good.

Fri Sep 11, 2015 10:40 am

Thanks Brian, I will check for leaks tonight and get some photos of the spark plugs.

Fri Sep 11, 2015 11:25 am

check the fuel pressure regulator (FPR), this can be quickly done by pulling the vacuum line off it to see if there is liquid fuel there (there is not supposed to be any) and /or fuel pressure tester to check fuel pressure

Fri Sep 11, 2015 12:40 pm

Brianmoooore wrote:Obvious thing is are you sure it's not just a simple leak? Have you stopped on the road with the engine running and carefully checked for drips and damp patches?
If the problem is with the fuelling, then your symptoms don't necessarily mean the engine is running rich. A weak mixture will also use excess fuel and make the exhaust smell of fuel, as will a complete cylinder which is receiving fuel but not igniting it.
Take out the spark plugs and examine the colour of the tips. Pics. would be good.

It's very likely this. I had a similar fuel smell and could not find a leak, having put the 3.5bar pressure regulator on for the ECU swap and oh god do I have a leak now that there's enough pressure to get out the crack!

It is likely a cracked hose somewhere, the rubber hoses do not fair well with the ethanol content of new fuels, especially if they have been replaced with anything less than an R9 grade of hose.
The leak will likely be very small and hard to find.

Sat Sep 12, 2015 12:27 am

Thanks guys, will jack up the car over the weekend and investigate.

Planning to change the fuel filter as well, Bosch or Mann fuel filter ..... What would you guys recommend?

Will keep everyone updated with the progress

Thanks

Tue Sep 29, 2015 9:52 am

Guys,

I have carried out the following:

Oil change
coolant change
fuel filter change
valve adjustment
air filter change
oil filter change

The car sounds and drives much better, but the fuel consumption is still bad. I have checked the vacumn pipe from the FPR and no sign of fuel.

I am weak in identifying the fuel pipes around the car, please can someone advise the total number of pipes that make up the fuel system to check so I don't miss any out.

I assume this will be checked when the car is running.

Again thanks for the advise