Fuel pump and Compression test readings do they look ok?

[cypriot_boy_2k7]

Well my fuel pump is whining not very loud but you can hear it even in motion and it fluctuates in tone, also the car idles ok but sounds like a slight gasp for more fuel, the note changes on the pump when this happens.
Can running lean make your car have bad MPG? is there any test that can be carried out? apart from the ones in the wiki?

Done a compression test today these are the results:

CYLINDER 1
Thread is a bit oily for some reason



COMP


CYLINDER 2



COMP


CYLINDER 3



COMP


CYLINDER 4



COMP

[cypriot_boy_2k7]

has the zone gone dead

[rich318i]

pressure looks good but them plugs dont, u had a mahine put on it see it there is any fault codes?

[cypriot_boy_2k7]

pressure looks good but them plugs dont, u had a mahine put on it see it there is any fault codes?

nope not had it on any machine, i think that it hardly tells you anything anyway, or am i wrong

[rich318i]

if a sensor is not working it well, what enigne is it?

[cypriot_boy_2k7]

its the M40 316i

[rich318i]

u in se london m8? cos can recommend a garage

[lamby]

any mot station will check mixture,running week can cause bad mpg as a dozen other things,comp fine,as for plugs hard to say,best take it on a run and look again

[kam-325i]

Pressures are good.

get your emissions checked with a CO meter.

[cypriot_boy_2k7]

I have a co meter I will check it in the morning. Am I right in sayin that the compression test still don't rule out that maybe valves won't be seating properly?

[kam-325i]

if your valves are not seating properly, you wont get those high pressure readings you have.

If the vales are leaking, then the compression readings will be low. your lowest reading of 13.5 bar/195 Psi is a very good reading.

[cypriot_boy_2k7]

if your valves are not seating properly, you wont get those high pressure readings you have.

If the vales are leaking, then the compression readings will be low. your lowest reading of 13.5 bar/195 Psi is a very good reading.

I see what you mean, true but have I done the correct procedure.

All plugs out, dme relay out, fuel pump fuse out, ignition coil disconnected.
Open throttle fully and let it tick over between 4 or 5 times each cylinder?

[kam-325i]

thats correct.

[cypriot_boy_2k7]

Cheers kam, I'll do a co test tomorrow see what the outcome is

[DanThe]

If you have bad MPG it will be running rich, which is exactly what those plugs are telling me

[cypriot_boy_2k7]

If you have bad MPG it will be running rich, which is exactly what those plugs are telling me

If this sounds weird please tell me, I have read somewhere that the return line to the tank or in the tank could be corroded and not allowing fuel to be returned thus going to the easiest exit which is then the injectors, thus making it run rich?

[HJG-E30]

That compression is very good.

However I'd replace those plugs with standard NGK single electrode plugs

[cypriot_boy_2k7]

That compression is very good.

However I'd replace those plugs with standard NGK single electrode plugs

Do you have a link?

[Speedtouch]

The plugs look OK to me - light brown/tan deposits is good.

Driving in London is bound to have an adverse effect on mpg - it probably needs a decent run to clear out the carbon deposits.

What sort of mpg are you getting?

[cypriot_boy_2k7]

The plugs look OK to me - light brown/tan deposits is good.

Driving in London is bound to have an adverse effect on mpg - it probably needs a decent run to clear out the carbon deposits.

What sort of mpg are you getting?

I'm getting around 18mpg, but I think that's inaccurate as it only filled up 35 litres to full when it was showing empty, I'm going to fill it up wen it gets low again and work it out.