What does the Leak Detection Pump (LDP) V144 do?

[GetBoosted84]

I just found a boost leak on my car. It was coming from the T under the intake manifold that attaches to the EVAP Canister Purge Regulator valve (N80), the Leak Detection Pump (V144), and a port below the intake manifold.

I tried to just put new clamps on the plastic T but that didn't work out so well. It just continued to leak. Because of this I opted for the easier solution and I pulled the T out and plugged the line running to the intake manifold port and left the other two open (Evap and LDP). The car runs fine, builds boost a little bit quicker, and I am getting no CELs so I'm assuming I am in the clear but I wanted to make sure.

I did a search but I'm not pulling up any information on the LDP or what it does.

Recap:
* What is the leak detection pump?
* What is its purpose?

For reference. The T I am referring to is located between 19 and 18:

* Please note the above diagram is for an ATW engine I believe. In my Bentley manual, that intersection is marked as 16 and 15 from page C 21-2

Thanks!

[Rhinop21]

I believe it detects leaks, im not exactly sure though ;)

[GetBoosted84]

I believe it detects leaks, im not exactly sure though ;)

lol, I was thinking that but then I wasn't sure because it's name is so damn obvious that it couldn't be that simple.

I know it detects leaks... what kind of leaks I have no clue. I'm assuming vacuum leaks although that's just my 2 cents and I have nothing to back that up.

[GetBoosted84]

Ok, so the not having a code thing didn't last long. Got a EVAP low flow code today so I am going to reconnect it with some better clamps and a new Tee. Still not sure if the LDP is required though.

[fernando]

a leak detection pump detects vaccum leaks in your EVAP system

[GetBoosted84]

Ahh, that makes sense. Guess it's required then :-(

[k0mpresd]

i wouldnt say required. your current ecu likes it there though. ;) hahaha.

[GetBoosted84]

True true...

k0mpresd, what's the word on the PES tune hack btw?

[B5A4Kevin]

The LDP detects leaks in the evap system. however it does not detect vacuum leaks. fuel vapor builds in the tank and is sent to the charcoal canister for storage. under certain operating conditions, the canister is emptied via the n80 valve into the intake system so it can be burned rather than releasing raw fuel into the atmosphere. the leak detection pump is a checks the integrity of the system to ensure that the gas cap is tight, there are no cracked or broken hoses/lines (large/small evap leak faults), and that n80 isn't stuck open. i forget if it pressurizes the system or creates vacuum, but it does 1 of them, until a flap closes. then it counts how long until the flap re-opens due to re-equalized pressure. if it takes no time at all, large leak. takes longer = small or very small leak. does not re-open - no leaks. In terms of necessity, its not required for the engine to run properly, but it will set a mil, you most likely wont pass any emissions testing if applicable to your state (i love FL), and if you have an evap leak it will be detrimental to the environment.

[GetBoosted84]

Awesome. Thanks for the input guys. I'm going to re-install the tee splitter. I would prefer to keep that part of the car working.

[urban96]

If im getting code: 17884 - EVAP Leak Detection Pump: Malfunction / Insufficient Vacuum

What would that mean? I have a leak somewhere between N80 and LDP?

[walky_talky20]

It would most likely mean that the LDP is no longer getting it's vacuum source. I believe that would be #19 in the above diagram.

[cervantes559]

your car finally ran the evap monitor that's why your cel light came on it has to run to monitor like 2 times I it sees the same problem turns on cel
LDP is part of your evap system purpose to detect any leaks in your evap system..