Volkswagen Passat Forum banner

21 - 28 of 28 Posts

·
Registered
Joined
·
2,214 Posts
see if I interpret this correctly, you should not have a radical dip in STFT in the seventh block ? have you cleaned your MAP sensor, as it sometimes collects oil buildup ?
 

·
Registered
Joined
·
28,209 Posts
195 g/s on the maf is about 50% too high for a stock 1.8T. Time to replace it, make sure it's the correct number as several people have had the wrong one installed when they bought the car.

As for the SAIP, it can cause a vacuum leak if the diaphragm is blown in the combi valve. The vacuum leak would only occur when the SAIP is active.
 
  • Like
Reactions: cchief22

·
Registered
2003 Passat GLS 1.8T MT
Joined
·
16 Posts
Discussion Starter · #24 ·
see if I interpret this correctly, you should not have a radical dip in STFT in the seventh block ?
That was my though too, initially. However, if the STFT is being guided ONLY by the lambda A/F sensor (my understanding) then I interpreted the STFT dip (i.e. ECU is taking fuel away) to be in response to the "rich" signal coming from the lambda sensor (i.e. negative mA). Also, keep in mind that the LTFT is at +10.
have you cleaned your MAP sensor, as it sometimes collects oil buildup ?
I cleaned the MAF sensor.....does the 03 Passat also have a MAP sensor?
 

·
Registered
2003 Passat GLS 1.8T MT
Joined
·
16 Posts
Discussion Starter · #25 ·
195 g/s on the maf is about 50% too high for a stock 1.8T. Time to replace it, make sure it's the correct number as several people have had the wrong one installed when they bought the car.
Interesting. I didn't appreciate that a MAF g/s reading that exceeded the x0.8 rule was a problem. Especially for a turbo. So let me work this through...

  • A stock AWM 1.8T puts out 170 hp at 5900 rpm
  • Translates to 170 x 0.8 = 136 g/s at 5900 rpm
  • In my case the MAF shows 185 g/s at 5900 rpm
  • This indicates that the MAF is reading 36% higher than expected

Everything I've ever read about MAF sensors emphasized the problem with low readings. So I guess that blinded me to the other side of the scale. But would this explain the LEAN condition I've been dealing with? It seems to me that a higher than actual mass air flow would command the ECU to provide more fuel than required, causing a rich condition, not lean.....
 

·
Registered
Joined
·
2,214 Posts
the MAP sensor is sorta inconspicuous unless you have pulled it before, but if you go backwards from throttle body IIRC it is right before intake hose/tube/pipe gets to inter cooler. I believe it also contains the intake temperature sensor as well. Mine worked ,how well I do not know, but it was sorta goopy with oil residue.
 

·
Registered
Joined
·
28,209 Posts
The MAP sensor is on top of the intercooler, the intake temp sensor should be on the intake manifold.
 

·
Registered
Joined
·
2,214 Posts
The MAP sensor is on top of the intercooler, the intake temp sensor should be on the intake manifold.
The MAP sensor is on top of the intercooler, the intake temp sensor should be on the intake manifold.
Thanks for correction......for some reason thought there was more than 1 sensor/device/combo going on down there
 
21 - 28 of 28 Posts
Top