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Vacuum line stalling engine when connected to nvld

3477 Views 48 Replies 5 Participants Last post by  Bob Lincoln
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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Welcome to Allpar. Year? N/A or turbo?

Can you post an image? Where do these hoses go to?
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I'm not seeing a vacuum pump on that model. Is there an underhood vacuum label that you can use to identify the part?
May look something like this:

I would not run without an EGR valve if it is equipped for one.
The fuses & relays should all be in the PDC, unless someone added an in-line fuse for an accessory?
The PDC lid should identify the fuse/relay positions.
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It may not need a purge valve. I've had purge valves stuck open because a piece of charcoal from the charcoal canister got sucked up into it. Can you blow through the valve?
If the canister is loaded with raw fuel, it can allow for a rich mixture. Do you smell a strong odor of fuel?
Either condition may or may not cause a stall. Always diagnose first.
The canister is in the back on the fuel tank.
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There is no purge valve on the throttle body.
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A service manual for this car would help & maybe pay for itself:
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If you block the end of the hose with your finger, does it stall? Or only when plugged in to the purge valve?
If the charcoal canister is flooded with liquid gasoline, it may stall the engine by being too rich. It is supposed to store fuel vapor only.
If you install the hose onto the valve slowly, allowing it to stumble & recover, but not stall out, can the hose be installed all the way with the engine still running?
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There is only one purge valve. It is the one under the brake booster.
(an undercar image looking up at it):

The NVLD is at the rear of the car on the fuel tank next to the canister.
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Someone added that fuse into the wiring. It doesn't look like something the factory would use.
Did you just buy this car or know any of its past history?
The factory does not use '3-pin fuses laying on top of the valve cover to the ign coil', if it is a fuse.
The 'wedge' adapter that the 'fuse' is plugged into is more reminiscent of a bulb.
I suggest not replacing parts until you can better diagnose this stalling.
OEM parts are an important consideration.

Apparently the previous owner did some modifications with extra wiring? Where does this in-line fuse wire go? Was the car running with the purge hoses intact when you got the car?

We might need more details about why the engine was swapped and if this is the correct engine for the car? Was this donor engine running before the swap?
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