Volkswagen Passat Forum banner
1 - 20 of 26 Posts

·
Registered
Joined
·
147 Posts
Discussion Starter · #5 ·
THanks! Makes sense air or vacuum leals!
When car starts it idles roughly. When it reaches closed loop it smooths out. As long as car has been driven and not cooled off below open loop it is fine. Always used High Test gas and only major problem locked up throttle body with some type of rubber pieces keeping throttle plate from opening or closing! I removed and cleaned and went threwVAG procedures for idleing and clearing codes
 

·
Registered
Joined
·
147 Posts
Discussion Starter · #6 ·
First start up idle not smooth on open loop! This is a 2.8 with 88,000 miles. After warm up smooth idle! No codes. Always used 91 or better octane since i am original owner. No hesitation in open loop runs fine Any other owners have this problem?
 

·
Moderator/Administrator
Joined
·
26,297 Posts
Let's try to keep this to one thread, please. Merged with other one you just posted. If you want to change the thread title, feel free.

How old are the plug wires?
How many miles on the plugs?
Is the throttle body clean?
When did you have that issue with the throttle body being locked up?
 
  • Like
Reactions: AndreasPassat

·
Registered
Joined
·
7,970 Posts
I removed and cleaned and went threwVAG procedures for idleing and clearing codes
Now I'm confused. Did you or did you NOT have any codes?
Just curious, how rough is rough idle? The V6's aren't super smooth at idle.
Maybe a short video?

And, what VAGguy said.
 

·
Registered
Joined
·
147 Posts
Discussion Starter · #9 ·
Let's try to keep this to one thread, please. Merged with other one you just posted. If you want to change the thread title, feel free.

How old are the plug wires?
How many miles on the plugs?
Is the throttle body clean?
When did you have that issue with the throttle body being locked up?
Wires original,plugs have 20 thousand miles on them,Last December removed and cleaned was gummed up with a rubber band black substance i assumed when fuel filter was changed something got digested in the fuel system.
 

·
Registered
Joined
·
147 Posts
Discussion Starter · #11 ·
Now I'm confused. Did you or did you NOT have any codes?
Just curious, how rough is rough idle? The V6's aren't super smooth at idle.
Maybe a short video?

And, what VAGguy said.
Here is what i have at start as key is turned to start a mild poping sound is heard,and then it starts quickly and runs rough and is getting rougher over time. This did not happen after relearning TB.Give it a few minutes of ideling and movement of vehicle and temperture reaches closed loof the idle smooths out!
 

·
Moderator/Administrator
Joined
·
26,297 Posts
No codes as of today 09/23/2022.Today i will run and check if there any codes.If not i will not post!
If your scan tool has the ability to look at sensor readings like coolant temp, that would be beneficial. If the coolant temp sensor reading is off (on a cold engine, it should be very close to ambient temps), the air/fuel ratio will also be off and can cause a rough start/run.
 
  • Like
Reactions: AndreasPassat

·
Registered
Joined
·
147 Posts
Discussion Starter · #13 ·
If your scan tool has the ability to look at sensor readings like coolant temp, that would be beneficial. If the coolant temp sensor reading is off (on a cold engine, it should be very close to ambient temps), the air/fuel ratio will also be off and can cause a rough start/run.
Thanks will check this morning ! It is 42 degrees as of now!
 

·
Registered
Joined
·
147 Posts
Discussion Starter · #14 ·
My tool does not read temperture? Look in bentley Book found its location on motor but could not find electrical test. I assume resistance might play in part in readings to computer lean or rich on start up.
 

·
Registered
Joined
·
1,935 Posts
Thanks is this when engine is cold in open loop or when warm what should it do the engine?
I don't know for sure but I would suspect that the ECU defaults to normal operating temperature if it gets no signal or an unbelievable signal from the temp sensor. So if it acts the same (rough when cold, normal when warmed up) it could be that the CTS is kaput.
 

·
Registered
Joined
·
147 Posts
Discussion Starter · #19 ·
I don't know for sure but I would suspect that the ECU defaults to normal operating temperature if it gets no signal or an unbelievable signal from the temp sensor. So if it acts the same (rough when cold, normal when warmed up) it could be that the CTS is kaput.
Where and how much should i pay for the temp sensor
 

·
Registered
Joined
·
1,935 Posts
Do you have a dealer nearby? This is one part I'd go with OEM or equivalent. They aren't expensive and the cheap ones seem to fail often. Make sure you get the one that goes at the back of the head (probably green). There is a similar part that will fit down by the lower radiator around but that is just a temperature switch that turns on the cooling fans and is usually black or blue.

Edit: - oh crud, I see this is a V6. Then I don't know where it goes but do get a good quality part.
 
1 - 20 of 26 Posts
Top