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airflow meter help

8K views 9 replies 5 participants last post by  iX guy 
#1 ·
does anyone know the symptoms of a bad airflow meter? how the car would start and idle. when its going bad. i believe i have a bad airflow meter. thanks :dunno: i have a 1986 325es 152000 miles
 
#2 ·
there usually is a flat spot off idle due to wear. Get a Bentley manual and test it. Also check and clean all electrical contacts. What are your symptoms? There are a lot of things that can cause problems. Also check your throttle body where the vacum fittings attach, if loose it is an air leak, clean the fittings with brake clean and either locktite or high temp sealer.

ovalbar
 
#3 ·
thanks ive been trying to get this thing to run for the last week. it was running great then just died one day on my way home replaced fuel pump and relay and have been cleaning all sensor connectors. it will start sometimes and run great but as of late will only start when giving it gas and will only run that way as soon as you take your foot off the pedal it stalls very hard to start. and i only have a fell strands of hair left to pull out. :cry: :dunno: thanks for any help in advance
 
#4 ·
You're luck, yours still starts. I had this problem with the air flow meter. It got out of balance some how and the car wouldn't turn over. I thought it was the fuel pump or a problem in the fuel line, but when I got the car looked at it turned out to be the air flow meter.
 
#5 ·
With the few strands left, check the ohm value reading of the air flow meter as you move it through the range, and check this against the info in Bentley. Also check the boots for air leaks. check and clean the idle motor. Check and clean the rpm sensor on the front of the crank. Clean the pins on the round connector below the intake manifold. There are 3 relays to check. There are many systems that affect the idle, so check them all. What are you cleaning the terminals with?
 
#6 ·
ive been cleaning all conectors with scotch bright pad and a razor to get corrosion off. i did do a check of my crank sensor and noticed it was not in the ohms range listed in my manuel. i was only getting 500 ohms. manuel says 800-1000 ohms and if not replace sensor. well im going to pull both sensors an check them out of car then decide what to do next both these sensors are about 100 bucks each so i want to be sure before buying new ones.
 
#10 · (Edited)
has the engine just a spot from what you can say it doesnt run smoothly or does the engine run with up's and down's (say like +/- 200rpm). and the engine stops in the end ?
if its difficult to start and it wont run idle after 1-2min and you have checked all connectors, hoses, resistances (on the airflow meter, tps, idle air stabiliser valve) then you should check the fuel pressure. i had the symptoms described above and it came out that the fuel pressure regulator was faulty. the fuel pump was making a loud noise and when we mounted a fuel pressure gauge it showed that the fuel pressure was going up and down from 2 to 6 bar. a new one costed here ~75$ but i needed the car to run a i got a used one for 7$ :)

sorry if its hard to understand - havent written technical english in a long time
 
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