940 poor fuel economy

Hadrian

Hi all. I have a non-turbo 940 that is using 14L/100. When I got the car it had 6 fault codes, I replaced some sensors and the ecu showed no codes. A few weeks later I got "MAF hot wire" code. I had previously replaced the MAF with a cheap no-name one.
It idles a little rough when cold but otherwise runs fine. Should I pay for a genuine Bosch MAF? I really don't want to spend $500 🥴

Major Ledfoot

Hadrian Should I pay for a genuine Bosch MAF? I really don't want to spend $500

Which is three full tanks of fuel....
You can get a good used genuine Bosch 016 air mass meter for far less than $500.
Because 17 MPG is ridiculous for these cars, you may also need to look at other things - e.g. new codes; brakes binding; a fuel leak, etc.
Fuel leaks from old fuel hoses aren't uncommon with 30+ year old high pressure hoses. Sometimes they don't even clue you in with a stink of fuel.
EDIT - seems you're not alone. Although this discusses a turbo, there's a few other things worth checking.
https://turbobricks.com/index.php?threads/poor-mileage-lh2-4-on-740t-what-wouldnt-set-codes.370779/

dmc

Getting a good second hand one will be simplier. someone here will have one or try the usuals (Voldat, Berrys) for a second hand unit. If it fixes the problem you know what to expect when the replacement eventually dies. the good/Bosch ones usually last 20 years.

ramrod

How did you determine 14l/100km, is it a sedan or wagon and what is the rear tyre size?

Hadrian

ramrod it's a wagon with standard tyre size. I measure the fuel used against the trip meter.

Anthony

A new MAF (Bosch if available) is always worth it, so you have a properly running car for the years ahead especially from cold start.

Hows the exhaust system muffler/cat for blocking up a bit, is it sounding wheezy or throaty?

They are heavy cars with a cruise diff ratio so In stop start driving use a bit.

Hadrian

Anthony it doesn't have a muffler currently so it's hard to tell if the cat is blocked, will have to look into it