I've taken a look at many of the threads around vacuum leaks but still not clear on an answer to my question, which i feel i should already know...but this past weekend didn't work out well so Monday should be no different.

What will happen if I gently drive the car about 6 miles in the city to the mechanic with a disconnected vacuum hose going to the LDP unit? I'm assuming engine codes will be thrown, but will it run ok and not put too much wear and tear on it? LDP already wasn't working, so obviously not worried about that.

Some background...

I attempted to replace the leak diagnostic pump on my '05 S (6 speed) and ran into trouble. The plastic bit the vacuum hose attaches to on the old LDP broke right off in the hose while trying to disconnect. Wouldn't have been a big deal because i was replacing it anyway... but, someone decided to use a ton of threadlock at the factory on the charcoal canister bolts, which have to be removed to get the pump out. One bolt came out fine, one did not at all. It feels like the metal bolt and nut are just spinning in the plastic sleeve. The nut isn't accessible... Anyway, after strugglnig for a couple hours my buddy and I gave up and decided to drop the car off at the mechanic tonight to let them have a go at it.

Thanks,
-Rob

 

It's OK to drive with a vacuum leak. The leak as well as the air volume/ pressure in the intake manifold will be accounted for by the MAP sensor, which means the ECU will continue to read the correct amount of air and supply the correct amount of fuel so as long as the air fuel ratio is correct you are OK.

The EVAP monitor will fail if it runs; it will run when the engine is cold and the fuel level is between a 1/4 and 3/4 tank. This is the only code you will get.

The lack of vacuum on the rail mounted fuel pressure regulator will increase fuel pressure at idle, but the fuel trims will go negative to compensate for the increased pressure. In my opinion you can drive the car normally without any damage.

Hope this helps!

 

It did, thanks! Mini drove perfectly fine to the shop...now waiting to here if they had better luck getting the stuck bolt out then I did.

-Rob