[leJUNd]

First I apologize in advance for posting a thread that does not concern e90 in e90 section but I really didn't know where else to go and this section draws a lot of traffic so I was hoping someone could help...

My gf has a 03 325i and she raised a concern about an unusual noise. Over 55mph under load, there is a slight vibration noise... the way she describes it dinging sound...glass cup vibrating sound...
It goes away when she takes the foot off the gas and comes back when she steps on the gas again. I really don't notice it when I drive it but she definitely hears it. I suspect it's pinging.

Now... she's been putting 87octane the whole life of the car, so obviously I think refueling with higher octane and seeing if that makes any difference would be the first thing to do... but if it's not the fuel, what could it be? timing? spark plugs? what would be the next step in correcting this? should she be concerned? again it's very very slight noise... I really don't hear it but she does. Any information regarding the topic would be much appreciated.

Thanks

[Johnny D]

I had an issue in another vehicle to what I feel may be similar. Turned out to be a clogged up catalytic converter. Under load merging on the highway it sounded like like pinging or metal rattling. Start there.

Next I would check the plugs and coils. Followed by injectors.

[flinchy]

I have to ask, in a decently powered car, not even just the fact its fairly expensive.. where even the manual states its better to use high octane fuel.. AND the fact you get more power out of it

WHY has she been using low octane fuel??????

Regardless of what caused the issue, i strongly suggest using the highest octane fuel available (98 RON max realiatically, though mine loves 100), disregarding anything else youll get more mileage and it has better additives for engine cleaning..

[leJUNd]

Originally Posted by flinchy

I have to ask, in a decently powered car, not even just the fact its fairly expensive.. where even the manual states its better to use high octane fuel.. AND the fact you get more power out of it

WHY has she been using low octane fuel??????

Regardless of what caused the issue, i strongly suggest using the highest octane fuel available (98 RON max realiatically, though mine loves 100), disregarding anything else youll get more mileage and it has better additives for engine cleaning..

She didn't
Her dad also told her, it didn't matter...

[mAdTYzz]

Sorry to be offtopic with this question but i don't wan't to start a new thread for this. So i live in sweden and as you know we have 95 and 98 petrol. i put in 95 octane petrol just because the fact that 2 times when i refueled with 98 from shell(not a random bensin station) the car felt like it had no power, And also the mileage was very poor. all in all the car felt unconfortable with 98 octane petrol, anyone has an ideea why that would be?

on topic: couldn't it be lifter noise what she hears?

[Ethanderall]

If she's a typical girl and drives like Miss Daisey, then there's a good chance that carbon build up on the piston crown or valves is causing detonation.

[flinchy]

Originally Posted by mAdTYzz

Sorry to be offtopic with this question but i don't wan't to start a new thread for this. So i live in sweden and as you know we have 95 and 98 petrol. i put in 95 octane petrol just because the fact that 2 times when i refueled with 98 from shell(not a random bensin station) the car felt like it had no power, And also the mileage was very poor. all in all the car felt unconfortable with 98 octane petrol, anyone has an ideea why that would be?

on topic: couldn't it be lifter noise what she hears?

Old fuel - stations that dont refresh the fuel often , old stuff goes stale

Or refinery could have had a bad batch etc. 98 is only worse if it's a bad batch, it has the same amount of energy in it as 95, just more resistance to detonation