316 1986 hunting very badly. can anyone help??!!

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user1830
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Fri Sep 10, 2010 7:32 pm

hi,
my 1986 316 is hunting. i took it into the garage assuming that all that was needed was the carb cleaned and it to be re-plumbed as there were rubber hoses hanging off it.

the mechanic said the base gasket was leaking air into the carb and making the mixture weak which makes sense. he replaced it.

now the car idles worse and cuts out. it was so bad i couldnt drive it away. can anyone shed some light on this please??!!
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e30mtec
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Fri Sep 10, 2010 7:38 pm

id look at te idle control valve..clean it up with carb cleaner
inspect all the vacuum hoses.mainly the main air intake one..if thats split..they cause all sorts
while ur there check the air intake rubber hose where it meets the throttle body ..underneath to the right slightly will be a small hose coming off it..into another hose...i had this problem and it turned out to be that..check the airflow meter is still plugged in.options are endless mate..its a sod of a job to sort out but when u fix it u will prob find its something stupid..good luck
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e30mtec
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Fri Sep 10, 2010 7:40 pm

get the engine running and take the oil filler cap off..let me know what happens..idles change or not?
user1830
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Fri Sep 10, 2010 7:43 pm

the hoses have been replaced and wired correctly according to the diagram..it has all been cleaned, or thats what i've been told and i have no reason to disbelieve my mechanic.
user1830
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Fri Sep 10, 2010 7:44 pm

i dont have the car... i couldnt drive it away from the garage it was running so rough
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e30mtec
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Fri Sep 10, 2010 8:06 pm

id look into the idle control valve then..take it off and clean it up with carb cleaner..usually loads of build up on them..if that doent work im stuck aswell lol
user1830
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Fri Sep 10, 2010 8:15 pm

cheers ill try that.. if you do get any other ideas please let me know 8)
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e30mtec
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Fri Sep 10, 2010 8:21 pm

will do pal..best of luck m8
Banjo1981
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Fri Sep 10, 2010 8:27 pm

It's a carb'd engine so I'm not sure it'll have an ICV...

Has the mixture been reset? If it's been leaking air for a while it may be that the mixtures all messed up. Failing that I would replace all of the vacuum hoses as they may have perished.
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e30mtec
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Fri Sep 10, 2010 9:32 pm

are they carbed? i thought they were just like a 318 4pot just smaller bored?..my bad if it is
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Brianmoooore
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Fri Sep 10, 2010 10:09 pm

A 316 is a carb. 1.8 (M10).
No idle control valve on these - the idle is controlled by a small actuator mounted on the carb. If it's not running right, either there's still another air leak, a jet in the carb is blocked, or adjustments were made to the carb when the previous fault existed to try to correct the running that now need to be reversed.
Trouble is, there aren't many of us around these days that know how to tune carbs!
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30316
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Fri Sep 10, 2010 10:34 pm

86 316 would be a carb engined M10. If I remenber correctly earlier ones were Solex carb and the later were Pierberg 2BE carb which is ecu controlled. I don't think you can adjust anything on the ecu controlled carb. The insulator between the manifold and carb does become porous over time so it would cause idle problems.

Your best bet is to get a carb gasket kit from dealers and clean the carb out which may help. Also check numerous small hoses on the carb to see if any are leaking. Similarly check the plugs/sockets on the carb to see they all make good electrical contact.

As most people do not understand the complex ecu controlled carb they ditch it and replace it with a Webber convertion kit which gets rid of the ecu.

All the above will not apply if it is already been converted with Webber in your case.
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E30k
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Sat Sep 11, 2010 1:36 pm

first join the club every one i know who had a 316 had this fault all the above i have tried i even got a manual on the carb and kit as well i got it going ok but not 100% perfect the main problem is as others have said no one really knows how to fix or understand how the carb works i even went to bmw to buy a new carb they had one but at £1100 it was a bit extreme you could get a ok 318i or do a engine swap cheaper if you want i can send all the info i have on this carb to you
user1830
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Sat Sep 11, 2010 3:20 pm

yes please that would be helpful.
all the plumbing has been replaced and the base gasket on the carb which was leaking air. the previous owner has replaced the sensors but had obviously been trying to fix the problem and had bodged most of it with springs and other strange items. once this had all been put back to the way it should be and the carb cleaned it was running like a bag of nails.
user1830
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Sun Sep 12, 2010 10:32 am

*bump*
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Brianmoooore
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Sun Sep 12, 2010 4:05 pm

Like I said above, either the carb adjustments are way out, or there's a blockage in it.
It's been a very long time since I set up Webbers!
user1830
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Wed Sep 15, 2010 9:43 pm

would the thermo switch have anything to do with it?
JJ26
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Wed Sep 15, 2010 9:57 pm

Sounds like you need to turn the idle mixture screw in a quarter turn, dont ask me where it is though cos every carb looks different...... ok not sure if this is the carb you got but found some usefull info for you.

http://www.bmwtechinfo.com/repair/main/421en/index.htm
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JJ26
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Wed Sep 15, 2010 10:36 pm

This Haynes manual showes some info aswell which might be helpfull.

http://www.e30.eu/tech/E30ManualHaynescomplete.pdf
G/90 316i M40 tickety tic!
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user1830
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Thu Sep 16, 2010 6:15 am

brilliant. thanks guys :cool:
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