bmw 316 1987 engine problems

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zigmund
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Thu May 15, 2008 4:13 pm

Hi,

I have a 316 bmw from 1987 with 1800 carburettor engine. When cold the engine starts properly and the engine goes fine , but when warm the engine stops running at every red light and is difficult to start ( i have to push the gas pedal at maximum) I also have the impression that the idle speed is about 100 rpm to slow. This i have tried to adjust , but it didnt seem possible on the 2BE pierburg carburettor. Spark plugs ,distributor and fuel filter have been changed recently. Valves are ticking , i plan on adjusting them. Any suggestions ?

Zigmund.
SPADGE
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Thu May 15, 2008 4:15 pm

Sounds like the choke is sticking on or the carb is fecked to me
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smithy318i
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Thu May 15, 2008 4:19 pm

you can change the idle speed by adjusting the throttle linkage attached to the idle control unit.
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DHFiS
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Thu May 15, 2008 8:30 pm

Its amazing that Pierberg carb is still working at all after 21 years, they do not have a reputation for reliability. I'd change to the Weber conversion with manual choke.
78dude
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Thu May 15, 2008 10:28 pm

Sounds like there is an issue with the Automatic Chocke on the Carburettor.... Maybe its time to give the carb an service with a new overhall kit and also check out the vacume house and hoses?
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Brianmoooore
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Thu May 15, 2008 11:02 pm

I did a post on this not long ago! The idle speed is controlled electronically using a vacuum operated actuator, with a variable resistor providing a feedback loop. The printed track of the variable resistor has worn out, so the feedback loop is open, and the idle is not controlled.
Not repairable as such (I once spent many hours trying!), so either drill and fit a conventional throttle stop, or change the carb for a manual choke Weber.
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zigmund
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Fri May 16, 2008 5:11 pm

Brianmoooore wrote:I did a post on this not long ago! The idle speed is controlled electronically using a vacuum operated actuator, with a variable resistor providing a feedback loop. The printed track of the variable resistor has worn out, so the feedback loop is open, and the idle is not controlled.
Not repairable as such (I once spent many hours trying!), so either drill and fit a conventional throttle stop, or change the carb for a manual choke Weber.
Is it possible to tell me where this variable resistor is connected.
I read in the haynes manual that it was possible to increase idle speed by connecting a resistor to the ecu , but than it says "go to your bmw dealer" , so i was wondering maybe if u knew where exactly this resistor must come and how many ohm it must be. Also i read on the internet that u can try connecting the wires of the airco (wich off cours i dont have) , this way the ecu will increase rpm.
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Brianmoooore
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Fri May 16, 2008 10:14 pm

It's about ten years since I played with one of these, so the memory is a little hazy! I think it's a white tubular structure, but the wires going to it should be a giveaway!
Without the resistor there is no feedback loop, so the ECU cannot attempt to control the idle speed, whatever bodges you use to try to fool it. The throttle just closes completely at idle, and the engine stalls.
I remember that I could drive the car OK by using a 'heel and toe' technique, but my wife ended up refusing to drive it, until I fitted a manual stop.
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zigmund
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Sun May 18, 2008 1:56 pm

Brianmoooore wrote:It's about ten years since I played with one of these, so the memory is a little hazy! I think it's a white tubular structure, but the wires going to it should be a giveaway!
Without the resistor there is no feedback loop, so the ECU cannot attempt to control the idle speed, whatever bodges you use to try to fool it. The throttle just closes completely at idle, and the engine stalls.
I remember that I could drive the car OK by using a 'heel and toe' technique, but my wife ended up refusing to drive it, until I fitted a manual stop.
Hi , today i took off my air filter and immediatly found the problem , the choke valve was jammed. So i unjammed it and put a little oil on the sides , now car runs very nice. Thanks for replying !
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