BMW Werkz banner

1 - 7 of 7 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter #1
I have a 1984 533i that is not holding idel. Once warn the engine goes into the strange cycle where it revs up to 1700 rpm and then back down to 1000 rpm and just keep going, back and forth as if it's searching for a corect idel rate. I can't afford to have a mechanic work on it. I know how to fix things, but this puzzels me to no end. any pointers from you BMW guys? I think it's vacuume related.
 

·
Registered
Joined
·
165 Posts
start with cleaning the idle slide valve.(attached to the breather hose coming off the V/C) spray a little carb cleaner, let it dry and then give it a shot of WD40.
 

·
Millions of them.
Joined
·
14,879 Posts
my dad's eagle was doing this... and it was a bad ECU . i dont know that anybody complained of BMW ECUs, but there is always a first
 

·
Registered
Joined
·
497 Posts
could be several things. What makes you think it's vacuum related? Did something occur to make you think so? It could certainly be vacuum related. I would check over all of your vacuum hoses and connections along with all of the intake ducting. As mentioned, I would also try cleaing your Idle air control valve. While it is idling and doing the surging, try tapping on the IAC with the handle of a good sized screwdriver. Sometimes those guys will stick and after a couple whacks, they will settle down. There is always a chance you could have an ECU problem and there could be other issues. Go with the easiest and obvious first.
 

·
Registered
Joined
·
82 Posts
I do not believe that this is an ECU problem. It is your idle control valve or a vaccum line that goes to it. Check the vaccum lines that go to that valve. If they are in good shape, take out the valve and spray carb cleaner in it and shake it well. you should hear a ball moving back and forth. This is good. spray a little WD-40 in it and shake it up. Re-install it. Also there is a screw in the valve that you can use to adjust the idle. If this does not work, you will need a new valve. They are not cheap!
 

·
Registered
Joined
·
29 Posts
I just saw this same exact problem on an E30 with an M20 and I suggested it was the Idle Control Valve, but that didn't help on this car, and it ended up being the ECU
 

·
Registered
Joined
·
2 Posts
If you need an idle valve,you may also find the idle conrl unit defective, Just cut it all out and install the factory euro idle control system for under 150.00. that will eliminate theentire foolishness of electronics controlling the idle. Then you will havenice simple mechanical devices contolling the idle,justa s BMW AG intended. I have done this on several at my shop and sold numerous others over the years
 
1 - 7 of 7 Posts
Top