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533i runs rough when warmed up
Posted: Aug 06, 2006 8:34 PM
by jac4
I recently aquired a 1984 533i 5-speed. Having only owned 2002s this car really hauls!! The car was garaged for at least 3yrs. I tuned it up and have one drivability issue still. When first starting cold the car runs fine. When the temperature gauge gets to the halfway point it starts chugging at times especially when accelerationg hard. Almost like lack of gas. I changed the fuel filter to no avail. Should the electric fuel pump next to the fuel filter turn on when the ignition is on (like a tii) but not started? When the car starts the pump runs. Could it be the coolant temperature switch or one of the fuel pumps? Any help would be really appreciated. Thanks, Jac4
hard start
Posted: Aug 06, 2006 9:34 PM
by adams5r
trouble shooting mine right now
there is a second fuel pump in the tank. when it is supposed to run I dont know but i have symptoms like vapor lock occationally.
from my experience, i could only get the out of tank pump to run when the car is running.
Rumor is that the "in tank" pump was some sort of BMW after thought for us cars because they were experiencing problems in hot weather.
you probably wont get stranded anywhere, I drove 400 miles today. get a pump from a junk yard (that works) and see if it makes a difference. ($275 from BMW #$@+)
Adam
84 533 5 speed 225K - current
81 e 12 auto white
82 e 12 manual grey
93 e 34
89 e 34
Re: hard start
Posted: Aug 06, 2006 11:11 PM
by Shawn D.
adams5r wrote:there is a second fuel pump in the tank. when it is supposed to run I dont know.
It's on the same electrical circuit as the main fuel pump. Thus, it is supposed to run when the main pump is running.
adams5r wrote:Rumor is that the "in tank" pump was some sort of BMW after thought for us cars because they were experiencing problems in hot weather.
You can tell the voices in your head to stop telling you such nonsense -- it's on all E28s, worldwide.