Vacuum line stalling engine when connected to nvld

Aniline said:

. . . Does anyone know why when I connect the 2 vacuum lines 1 from plenum the other on to of throttle body the engine cuts off on idle. Do these lines go to a vacuum pump Defective? . . . .

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Aniline said:

Does anyone know why when I connect the 2 vacuum lines 1 from plenum the other on to of throttle body the engine cuts off on idle.
Do these lines go to a vacuum pump? Defective?

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AllanC said:

As ImperialCrown stated we need to know specific make, model, year and engine configuarion, 4 cylinger, V6, V8, and some images of the vacuum lines in question to make a reasonable, accurate diagnosis.

Now if you wanted a "wild guess" I would say one of the suspect vacuum lines might be connected to the EGR valve. Fully activated EGR (exhaust gas recirculation) will stall an engine and stop it from idling. But again just a guess. Give more detailed information as requested.

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Aniline said:

Sorry I forgot it's the base model, non turbo 2003, it seems it goes to a vacuum pump, in a real awkward place below the breaker booster, I'm hoping it's not the pump. I did an engine swap, on a car that was not running.
I also came across a relay,/fuse yellow and orange in color, 3, pins that fell off and I cannot find where that plugs into, wondering if that had something to do with it

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DODGEBOYS.NET said:

the "pump" he is talking about is the NVLD pump and it's below the master

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AllanC said:

Ufortunately some of the drawings in a factory service manual are mislabeled. In post #6 presented by ImperialCrown the trapezoid symbol that is labeled 2.7L would make you think that symbol represents the engine. It should be labeled as the vapor canister. See attached image.

View attachment 89124



The device that provides pumping action and applies a vacuum to the fuel tank and evaporative system is the purge solenoid that is mounted under the power brake booster. The NVLD device vents over pressure, cleansed air to the atmosphere and seals the tank under a vacuum. It is located along with the vapor canister at the fuel tank.

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Aniline said:

Does this control the vacuum pressure

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AllanC said:

As ImperialCrown stated we need to know specific make, model, year and engine configuarion, 4 cylinger, V6, V8, and some images of the vacuum lines in question to make a reasonable, accurate diagnosis.

Now if you wanted a "wild guess" I would say one of the suspect vacuum lines might be connected to the EGR valve. Fully activated EGR (exhaust gas recirculation) will stall an engine and stop it from idling. But again just a guess. Give more detailed information as requested.

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AllanC said:

It is difficult to envision the dislodged. vacuum hoses on your vehicle without an image. If you can take a picture and post that would be helpful. Otherwise find the underhood vacuum diagram and connect lines as shown.

From a view into the engine compartment all you will see is the purge valve under the brake booster. There will be a vacuum hose from the purge valve that connects to a line under the body that runs to the vapor canister mounted on the fuel tank. The purge valve will have another port with a vacuum line that attaches somewhere on the intake plenum.

Follow the larger hose from the brake booster to the intake system. At the intake is there an open port with no vacuum hose attached? If YES this port with missing hose should have to be connected to the purge valve.

This connected vacuum line should agree with the underhood diagram. If the engine stalls at idle with this configuration, it is possible that the purge valve is stuck open. With a stuck open valve the engine is drawing in rich fuel vapors and the overly rich air-fuel ratio is causing engine stall. Just a guess on my part.

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