Question about BMW 318

1 Answer

I need the vacuum line diagram for 1991 bmw 318is

Posted by on

  • Harold Kimbrough Jul 13, 2010

    very good info,thank you



1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 20 achievements.


    An expert that got 10 achievements.


    An expert that got 5 achievements.

  • Master
  • 2,272 Answers

RED: Intake Boot to Idle Air Control Input
GREEN: Idle Air Control Output to
Throttle Body Vacuum Port
BLUE: Engine Vent to
Throttle Body Vacuum Port
YELLOW: Fuel Pressure Regulator to
Throttle Body Vacuum Port

i need the vacuum line - ad0567d.jpg

Posted on Jul 12, 2010

  • raj somaiya
    raj somaiya Jul 12, 2010

    The vacuum line you speak of is for the fuel pressure regulator
    the other end hooks to a fitting on the side of the throttle body to get vacuum. hose
    on the end is connected to the front vacuum port just above the throttle body
    and under the air plenum's.There are three hoses in total.

    There are two on the top, one goes towards the fuse box above the
    steering column, the other goes straight up. Then there is one on the bottom
    that goes straight down.

    With the solenoid not activated, the airflow passes thru from the horizontal
    one at the top to the bottom one pointing down.

    the vacuum line for the secondary air was connected to the oil
    seperator by way of the fuel rail. 

    intake manifold is designed with a vacuum actuated flap that divides the
    interior. The flap will open and close depending on engine speed and throttle
    position. The two positions form a long path and a short path for the air to
    flow before it is drawn into the intake runners for each cylinder. By changing
    the effective length of the intake manifold, the intake pulses of air will
    resonate at differing frequencies. By varying the resonant frequencies as the
    engine speed varies, a greater ram effect can be achieved.

    For the
    flap to actuate, two conditions must be met. The throttle must be at full open,
    with the full throttle switch closed, and the engine speed must be less than
    4120 rpm or greater than 6720 rpm. If these conditions are not met, the flap
    will not actuate. When these conditions are met, the resonance flap control
    unit will signal an electric vacuum switch to open allowing vacuum to operate
    the flap. A tolerance of 60 rpm in each direction for the engine speed
    switching points prevents constant motion of the flap if the engine is operated
    at exactly either of those speeds.

    On cold
    engine start-up, the resonance flap control unit does a self-check. The flap
    will be actuated and can be watched as the linkage moves. The electric vacuum
    valve has battery voltage applied to one terminal and the other terminal goes
    to the control unit. The control unit will ground the terminal allowing the
    circuit to be completed.

    resonance flap control unit is located under the relays in the electronics box
    mounted in the engine compartment. The electric vacuum valve is located under
    the intake manifold next to the oil trap. The flap actuator is attached to the
    intake manifold at the top and has a link connecting to the flap inside the

    The vacuum source for the system is a vacuum
    reservoir mounted below the intake runner for cylinder 5. The vacuum tank is
    necessary since there would not be enough manifold vacuum to operate the flap
    at wide throttle positions. A check valve prevents loss of vacuum from the tank
    while the manifold vacuum is low or when the engine is not running. The tank
    provides enough vacuum for 6 operations of the flap without manifold vacuum.

    Thanks. Keep updated for any more query. You can rate this
    solution and show your appreciation.





1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
New users get to try the service completely Free afterwhich it costs $6 per call and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

1995 bmw 318is

should work since both OBD 1

Jul 10, 2013 | Cars & Trucks

1 Answer


this is a good sized job to tackle if you are very good only attempt this first remove the cosmetic plates on the engine then go to the trunk and disconnect the battery then back in the engine compartment you will remove the injector harness then the fuel rail then the intake manifold then you will have access to the starter motor before re assembling you need to purchase new intake manifold gaskets this is the perfect time to install new injectors, Vacuum lines, fuel filter job takes me about an hour to do.

Feb 04, 2010 | 1994 BMW 3 Series

2 Answers

Accelerate Problem BMW 1992 318i

a bad camshaft position sensor or a vacuum leak. Most likely sensor. Is your check engine light on? you can test sensors with an ohmmeter to determine if a sensor is good or not. It wouldn't be bad to check and make sure your coil packs aren't bad by checking each plug for spark. You can lay one plug and wire at a time one engine so end probe of plug is fairly next to metal. Have someone crank while you watch for spark.

Oct 01, 2009 | 1996 BMW 318

1 Answer

1991 bmw 318is 4 door 16 valve motor, runs hot and radiator cold

you may have bad waterpump,the impeller on pump may be borken, just because it doesnt leak doesnt mean its good.also could have exhaust entering cooling system (bad headgasket) if pump is good have a block test done.

Sep 29, 2009 | BMW 318 Cars & Trucks

1 Answer

How to install a 1992 BMW 318is - Pex Rear Brake

it may be just needing new rear brake shoes, sounds like they have reached the lining wear sensor...

Aug 02, 2009 | BMW 318 Cars & Trucks

1 Answer

95 BMW 318is fuse box

hello, for your vehicle the fuses for the front power windows are 14 and 19. Both fuses should be 30amp fuses.

Mar 24, 2009 | 1996 BMW 318

2 Answers

My bmw 318is instrument cluster doesnt work

Common problem on BMW's apparently...there are on-line repair services but they are NOT cheap...100-300 bucks. Tough to fix yourself...unles you are a highly skilled techie!

Mar 24, 2009 | 1996 BMW 318

1 Answer

1991 318is BMW Heater want heat.

could be heating control valve ( not cheap ) or could be air in the system.

Oct 02, 2017 | 1992 BMW 3 Series

5 Answers

I Need 1995 bmw 318is drive belt diagram

All belts are easy to work out how to put back on, never needed a diagram in my life, 1. Did you take the belt off? 2. If so and you don't remember how to put it back your and idiot for not drawing a diagram for yourself first. 3. Just go to workshop and get them to put it on. Every person that pops up a bonnet thinks they are mechanic. These are the people don't have clue what they are doing brake and destroys things then come and disturb me while i'm working to ask me how to fix it. These **** are on drugs why the **** would I tell them how to do it something when doing that is my bread and butter. Didn't go to trade school for 4 years to tell other **** how to do it. & THIS TRADE IS THE HARDEST TRADE NEVER STOP LEARNING NO MECHANIC KNOWS EVERYTHING AND WAY UNDERPAID.

Jul 19, 2008 | 1996 BMW 318

Not finding what you are looking for?
Cars & Trucks Logo

Related Topics:

1,091 people viewed this question

Ask a Question

Usually answered in minutes!

Top BMW Experts

Frankie B

Level 2 Expert

65 Answers

Fred Sops

Level 2 Expert

272 Answers


Level 2 Expert

254 Answers

Are you a BMW Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides