Volvo RWD 140-160 Forum

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Vacuum system leak 140-160 75

I have a Vacuum system leak on my 164e which i cannot locate.

Auto runs rich. Engine volume drops when air temp sensor is connected. Engine runs well when air temp sensor is off line.

All FI components, sensors have been replaced. ECU is reman.

Auto will not run after 10 minutes of idle or five blocks of driving.

Engine shuts down. Will operate well after cool down period.

Questions:

Is the Vacuum Pump only for the Brakes or the entire system?

What type of leak detector can i use to pin point the problem.

Are vaccum rebuilt kits available for this vechicle?








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    Re: Vacuum system leak 140-160 75

    To: L.K. Tucker: In the past, when I have posted questions and included my E mail address, I have received copies of the replies to my original question which were posted by others. However, in this case, I was responding to the original posting by Bill so I assume he got my reply, same as he would have received all others. But in order for me to read your follow up question about who gets replies, I went back to the original thread. Dont know whether or not that is responsive to the question you are asking. Perhaps the Brickbopard webmaster can tell us how this is supposed to work.








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    Re: Vacuum system leak 140-160 75

    /// These years were bears for air leaks. Use a spray can of carb cleaner to spray around the intake manifold while the engine is running. The worst case is that it is on the bottom of the manifold head joint (hard to get to). The fact that it runs until it heats up is the reverse of my experience for air leaks. They normally run poorly until the parts heat up and expand.

    Failure on heat up points to a possible electrical problem. I mean you may have more than one problem. If you do not immediately find the air leak---move to eliminate a resistance caused failure in the primary electrical circuit. That is the battery, either or both battery clamps, and the red positive system wire. In my 73 it goes to a distribution block behind the battery. The problem, however, will be in the cables amd their end clamps. In really high resistance you can feel the heat generated if you immediately go to the battery on failure.

    There can be a resistance caused problem in any plug in the system.








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      Re: Vacuum system leak 140-160 75

      The air temp sensor is not critical to operation. It supplements and refines other signals and inputs to the ECU. Therefore, you may have an electrical problem associated with this sensor. Try using an ohm meter and take a reading, with the engine cold, of the air sensor directly at the sensor and then at the ECU connector. The readings should be nearly identical unless there is excess resistance in the wires leading from the sensor to the ECU connector. If the resistance is much higher from the ECU end, suspect a b5d ground at the bundle of wires screwed to the manifold or badly frayed wires. Then take out the sensor, drop it in pretty warm water for a minute or so( just the sensor part not the electrical connection) and repeat the measurements from both ends. The resistance should be much lower.......but the same at both ends. If I remember correctly, the reading should be about 500 ohms cold and perhaps 150-200 ohms warm. Not absolutely certain of these numbers.

      As far as a vacuum leak goes, try using a long piece of plastic tubing. Run the car, put one end in your ear and move the other end around everywhere there are gaskets including the injectors, injector holders, manifold gasket, all the hoses and their connectors and the one way valve on the hose between the manifold and the brake booster. If there is a leak, you should hear a sucking or whistling sound. Good luck








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        Re: Vacuum system leak 140-160 75

        /// When you post a reply to one of the replies in the thread does the orgional post also get the E-mail? Did the origional post get acopy of Ira's reply to me?







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