fuel consumption after spark plug change

[grey]

Sorry if this has been mentioned before, but could someone pls post what your trip computer is showing as the avg fuel consumption for a 4.8i?
I used to get 16 liters/100km, recently after the spark plug change service by the dealers, fuel consumption is averaging at 25liters /100km. Is this normal since the plugs ate new?

[ard]

Is your ACTUAL mileage reduced?

Did the dealer do any programming/updates?

[motordavid]

Agree with ard...
run a couple of full tanks, in your normal driving routes, do the arith, then see what your mpg is, assuming you 'knew' the usual 'average' before the plug change.

Imo, current plug technology combined with spot on engine monitor electronics, EFI et al, allows for a long time/lots of miles before a set of new plugs will offer any benefit.

Maybe the genius tech left something undone or screwed something up during the plug change.
GL, mD

[grey]

Thx guys, reading on the cluster is 25litres/100km ( highway)
Actual calculation is 20litres/100km
I have only done two full tanks after the service
Like u said I'm not sure if they tightened properly. It's a reputed dealer , not sure if they used 2nd hand plugs

[JCL]

If it does turn out to have higher consumption, as calculated over several tanks, it is more likely to be from a hose or plug left disconnected than from used plugs.

[grey]

I've made an appointment with another mechanic (ex BMW ), ill see if he finds anything

[grey]

I got my mechanic to check the spark plugs, ended up replacing them as per my request.
He insisted that BMW dealers definitely would have changed the plugs if they have charged for it but when we took them off today they looked like they came from another car. My car has only done 13000 km but due to the age I was requested by the dealers to keep log book service up to date ( they ripped me off ).
Anyway... Rpm needle doesn't drop intermittently and I'm monitoring fuel consumption , so far it's settled to where its meant to be. Regarding dodgy plugs, I have no way of proving what dealers did with the plugs. Later
I will post a pic of the plug which they have meant to be replaced a month ago.

[ChuckG]

grey,
If your mechanic will write on your receipt that he removed very used plugs and replaced them with new ones. He is considered to be an expert and his word should be respected. Write a letter to the general manager of the BMW dealer explaining the situation and include copies of both receipts. My guess is that you will get your money back. Don't write the letter to the service manager as he will tend to defend his mechanics. I have received money back from a general manager before.
Chuck

[grey]

Originally Posted by ChuckG

grey,
If your mechanic will write on your receipt that he removed very used plugs and replaced them with new ones. He is considered to be an expert and his word should be respected. Write a letter to the general manager of the BMW dealer explaining the situation and include copies of both receipts. My guess is that you will get your money back. Don't write the letter to the service manager as he will tend to defend his mechanics. I have received money back from a general manager before.
Chuck

Yes I was thinking along the same lines, but I have no way of proving the age of the plug that Came off my vehicle, I might even send one of the plugs to BMW Aus, this is a serious issue and customers are being ripped off. My mechanic showed a few other sample plugs for me to compare and judge. I'm not letting this slip away..

[ard]

Send it to BMW? They'll laugh. This is a garden variety rip off- happens every day in retail. BMWNA might care if you had PROOF. You have nothing. BMW will do nothing more than say "this is an issue you should take up with you BMW retailer".

Have a heart to heart with the GM- have the plugs to show him. No getting crazy, no yelling- just 'your service team let me down and YOU need to know'