Volkswagen Passat Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter #1
Hi, need some help before I spent another couple of 100 on my car....

My car is a 2006 Passat 3.6 with a BLV engine. It has around 140k miles on it but now idles very rough. Fault reading told me to change the high pressure fuel pump. Tested my (suspected) Fuel Rail Pressure today the way it is showed in the YouTube Video of RossTech. My Passat and shows the engine light. During the test it shows a pressure of around 128 Bar. It doesn't tell me the specified pressure it should measure do I don't know for sure if it's to high - can anyone confirm please?

After shutting the engine down the pressure drops to around 118 bar right away, then slowly rises up to around 128 again if I wait 10 minutes. Does that indicate a leak? If a fuel injector is bad, or a fuel injector gasket is blown, is there a way to tell? I noticed the lambda for both rails around 20 (and specification is -10 to +10, it says). Can you please advise?

I see a lot of different high pressure fuel pumps on Ebay that look the same as mine - can I use any of them all?

Any help is welcome!!
 

·
Registered
Joined
·
35 Posts
Do you have a code that says it's the hpfp?

Have you carbon cleaned your valves?

It's a $15 test to use the dgi valve cleaner and see if it changes the idle characteristics.

Sent from my SM-S975L using Tapatalk
 

·
Registered
Joined
·
113 Posts
I’m much more familiar with the 2.0T platform than 3.6L so I’m not sure on proper fuel rail pressure specs but I can say this:

1) pressure can remain high and even drop then rise some even after car has been turned off due to the fact that the pressure only bleeds off slowly and temperatures in the rail and fueling lines will cause some fluctations in pressure. In other words, what you are seeing with pressure remaining high after shutting car off is not necessarily irregular. And no you don’t have a leak, if you had a leak you wouldn’t have pressure building properly. You should really include the exact code you are getting from vcds not your interpretation off it.

2) The thing that IS irregular is just how high your pressure is if that is at idle... correct me if I’m wrong but you are saying that it is at 128bar at IDLE? Again I don’t know exact specs for 3.6 fuel rail but I can tell you without a doubt that is waaaay too high for idle. That’s what a modified/tuned 2.0T fuel rail hits at full throttle, for some perspective. I’d doubt if your idle pressure should be any more than 70bar at most, but spec could be as low as 40bar. I’m really not sure but I’d bet proper spec is somewhere in that range. Sure as hell not 128bar.

3) Pretty sure you can ignore the guy above comment on cleaning intake valves... that is a 2.0T issue and not nearly as much an issue on your 3.6L as far as I know. Plus it wouldn’t explain your crazy high idle fuel pressure.

4) If your idle fuel pressure really is that high your running really rough because you’re injecting way more fuel that you should at idle and running extremely rich, to the point there is hardly enough air with the mixture for even combustion. Have you noticed darker and/or stronger smelling exhaust since this issue began?
 

·
Registered
Joined
·
35 Posts
I’m much more familiar with the 2.0T platform than 3.6L....

3) Pretty sure you can ignore the guy above comment on cleaning intake valves... that is a 2.0T issue and not nearly as much an issue on your 3.6L as far as I know. Plus it wouldn’t explain your crazy high idle fuel pressure.

If the op doesn't include scans and codes how sure are you that his rail pressure readings are reliable?

if you don't know about the 3.6 then are you qualified to comment about it?

I have BOTH the 2.0t AND the 3.6L. They BOTH require carbon cleaning.




Sent from my SM-S975L using Tapatalk
 

·
Registered
Joined
·
113 Posts
If the op doesn't include scans and codes how sure are you that his rail pressure readings are reliable?
I'm not, my statements were assuming that his scans and reports on the rail pressure were reliable. If they aren't then that's on him. I gave what advice I could with what I was given.

if you don't know about the 3.6 then are you qualified to comment about it?

I have BOTH the 2.0t AND the 3.6L. They BOTH require carbon cleaning.

I still keep my ear to the ground on the other VW engine platforms even though I have much more specialized knowledge in the 2.0T arena. That being said, while I'm sure the 3.6L requires some valve cleaning at some point I know plenty of people who have them too and between that, as well as plenty of forum material, the consensus I've seen is that it isn't nearly as big an issue on them as it is on the 2.0T platforms. That's mostly irrelevant anyway though because about the only thing that the OP brought up that dirty valves would relate to is the rough idle but there were a few things OP brought up that go beyond dirty valves (if we are to assume that what we were told by OP is accurate - and, again, if it wasn't then that's on him, you do what you can with what you're given).
 
1 - 5 of 5 Posts
Top