316 carb still not sorted

[wayneE30]

ok martin ive checked pipe 5 and there is a tiny bit of suction.


as i said before the engine is running at around 2000 to 3000 rpm with either carb on now im starting to think ive done somthing wrong the only new difference is i changed the rubber gasket for the one that came off the newer carb

[wayneE30]

anyone??????

[320Touring]

anyone??????

dude, chill-folks have given you plenty of advice, so work through it methodically, and if you want to keep it up near teh top just BTTT the old thread, dont start a new one mate.

its all gonna work out eventually cos there's only a certain number of things its gonna be.......

[wayneE30]

dont worry mate im as cool as penguins p1ss just trying to bttt

[Martinaston]

I keep missing you on here Wayne
You say you get a bit of suction but is that with the engine hot or cold ?
Try both and let me know.

Also flap in the top of the venturi is the choke flap and should be almost horizontal when the engine is cold and then gradually open as the engine warms up.

So check the suction at 5 when you first start up, put the pipe back and then check again when the choke flap opens. (if it does)

[wayneE30]

I keep missing you on here Wayne
You say you get a bit of suction but is that with the engine hot or cold ?
Try both and let me know.

Also flap in the top of the venturi is the choke flap and should be almost horizontal when the engine is cold and then gradually open as the engine warms up.

So check the suction at 5 when you first start up, put the pipe back and then check again when the choke flap opens. (if it does)

sorry mate should of said thats when its hot. when its cold theres no suction at all mate

[wayneE30]

although i will say theres hardly any suction at all

[Martinaston]

When the engine is warm the suction at 5 should be the same as at 2.
If it's not then you have a problem at 6, the thermal valve is not opening corrrectly.

That will be a judgment call on your part as to weather you replace it or not.

If it's not operating properly it will then cause a problem with the secondry throttle diaphragm assembly (1) and it's what controls the full throttle action.
You may be able to notice this when accelerating and you push the throttle more than two thirds of the way.
Accelerate slowly because when you do it too fast as is normal in an auto (even more so when the gearbox is worn) you will encounter the problem from the start and think it is something else.

Another way to check is to look down the secondry venturi (the one without the choke flap) and see if the butterfly at the bottom is opening when on more then half throttle.
that way is not as reliable though because you do not have the air filter housing in place and the engine is not under load

I could have been to banbury and back by now

[wayneE30]

I could have been to banbury and back by now

that would of been better


so replace the therma valve then how much would it cost do u know????

[Martinaston]

Check the suction at 2 and 5 when warm to see if there equal as it may be a problem with the secondry throttle diaphragm assembly (1). and not the thermo valve.

There's no point replacing thing's unless your sure there knackerd, otherwise you end up spending more money and when you add it up you realise you could have bought a new car

[wayneE30]

ok will do that in the morning mate and let you know cheers mate

[Martinaston]

Now for the silly question i should have asked at the start

Have you changed the fuel filter ? Clear plastic one below manifold (about Ԛ£1.30)

[wayneE30]

yes mate brand new one when i got the car

[wayneE30]

ok martin we have suction at 2 but none at 5 i waited till the engine was at 1/2 temp and nothing

[Martinaston]

If your sure it's not working then have a look here (the second number six) that should be about Ԛ£10 in real money, thats the part number on the right.

http://www.realoem.com/bmw/showparts.do ... g=11&fg=35

Did you try driving it on less than two thirds throttle ? Or having a look down the venturi?

[wayneE30]

[wayneE30]

i never looked down the venturi because you said

that way is not as reliable though because you do not have the air filter housing in place and the engine is not under load

and i never took it for a drive because im too scared id have to walk back

[Martinaston]

you may still have other problems if the carb is worn

[wayneE30]

what like mate

[Martinaston]

Does the choke flap open as the engine warms up ?

This is controlled by the ECU and that gets its signal from another temerature sensor

Number 4 in that like from my other post

[wayneE30]

i dont know mate will have to go and have a look and get back to you on that one

[wayneE30]

but i do now have two carbs and at least 1 of them works

[wayneE30]

Does the choke flap open as the engine warms up ?

This is controlled by the ECU and that gets its signal from another temerature sensor

Number 4 in that like from my other post

not realy mate it just flaps about and does nothing it moves when you swich the ignition on but does nothing after that

[Martinaston]

As long as it is moving when you turn the ignition on and off you know that it works.
What we don't know is weather its being set to the correct position for the right engine temperature.
It should turn from the horizontal as the engine reaches working temperature.
You may not notice it as much because of the warm weather.

Also do you own a mutimeter ?

[wayneE30]

Also do you own a mutimeter ?

no mate sorry

[Martinaston]

Can you borrow one ?

[wayneE30]

i doubt it mate am i gonna need to invest in one

[Martinaston]

Hopefully not
The temp sensor is either 8 or 9 but i'm not sure which one is for the ECU and the other is for the temp guage.





Disconnect one at a time and see if the temp guage drops if it does you know its the other one that works the choke.

When you know what one is for the choke with the engine cold again pull the connector on and off and see if the choke moves.

[wayneE30]

[wayneE30]

ok 8 is the engine temp for the gauge inside the car
9 i have no idea

[Martinaston]

If 9 is for the choke then it may not do anything unless the engine is stone cold.

Have a look for a third sensor thats screwed into the manifold.

If there's not one there then i'd say replace the thermal valve (6) and if that don't cure your problems you will then have to buy a multimeter to check the temperature sender or just get a new sensor as well but you may be wasting your money.

[wayneE30]

ok mate i will have a look and let you know

[wayneE30]

nope no more sensors

[Martinaston]

Right before you start buying new bits warm the engine up then pull the pipe at 2 and plug it in to 5 so you bypass the thermal valve and go for a drive.

Does it cure the problem ?

[Richy325iTouring]

have you check or changed the relay under the black box on n/s front wing