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Old 06-26-2019, 09:26 AM   #11
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Looking at the freeze frame data it says......

O2S B1 S1 = 0.05
O2S B1 S2 = 0.85
O2S B2 S1 = 0.88

So that bank 1 sensor 1 is way off compared to the other two. Could that mean a bad sensor?
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Old 06-26-2019, 11:16 AM   #12
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Is bank 1 sensor 1 the top one? (picture is looking from the top of the engine, you can see 3 O2 sensors.)

Which would be the grey connector?
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Old 06-26-2019, 07:04 PM   #13
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Bank 1 upstream O2 sensor is the sensor in the exhaust manifold, closest to the engine.

That is where I would start, though unlikely where you'll end.....
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Old 06-27-2019, 07:07 PM   #14
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Anything jump out? When I checked the o2 sensors. #2 and 3 were steady. Number 1 was jumping all over.
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Code P0171 System too Lean. (not the PCV hose)-47936286-2210-4153-ab7c-266434ff7d92_1561676489399.jpg  

Code P0171 System too Lean. (not the PCV hose)-193c11f3-5684-4adf-a751-7d51c0c51cfe_1561676544039.jpg  

Code P0171 System too Lean. (not the PCV hose)-890c21b7-d545-4945-ab6c-6ee1257eeae2_1561676602423.jpg  

Code P0171 System too Lean. (not the PCV hose)-697a6b1a-a64a-4762-92f7-ce965e009ba5_1561676631704.jpg  

Code P0171 System too Lean. (not the PCV hose)-d1e0cb8e-eda5-4a31-a613-5643dfe657ec_1561676672153.jpg  

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Old 06-27-2019, 10:38 PM   #15
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Quote:
Originally Posted by Stangfire View Post
Anything jump out? When I checked the o2 sensors. #2 and 3 were steady. Number 1 was jumping all over.
In general the upstream O2 sensor (S1) should cycle between 0.1 and 0.9 VDC and if your cat is working correctly the downstream O2 sensors should have a fairly constant output voltage of about 0.4 - 0.6 VDC.

Your LT FT of 21.1 is pretty high (lean).

Your RFP of 312.8 kPa (45.37 psi) seems high to me - I believe the spec is 39-41 psi. Perhaps that is the system trying to respond to the lean condition.

A common reason for a lean code without any apparent unmetered air leak (vacuum leak) is a dirty MAF sensor. Have you tried to clean the MAF sensor?

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Old 06-27-2019, 11:05 PM   #16
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Need some info on no lights on dashboard 2003 mk1 SVT. Replaced light bulbs and no luck at all.

Any help will be appreciated
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Old 06-28-2019, 11:14 AM   #17
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Need some info on no lights on dashboard 2003 mk1 SVT. Replaced light bulbs and no luck at all.

Any help will be appreciated
glbikefixer,
Please start a new thread
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Old 07-02-2019, 09:22 AM   #18
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Quote:
Originally Posted by Paul1958 View Post
In general the upstream O2 sensor (S1) should cycle between 0.1 and 0.9 VDC and if your cat is working correctly the downstream O2 sensors should have a fairly constant output voltage of about 0.4 - 0.6 VDC.

Your LT FT of 21.1 is pretty high (lean).

Your RFP of 312.8 kPa (45.37 psi) seems high to me - I believe the spec is 39-41 psi. Perhaps that is the system trying to respond to the lean condition.

A common reason for a lean code without any apparent unmetered air leak (vacuum leak) is a dirty MAF sensor. Have you tried to clean the MAF sensor?

Paul
Yeah I've cleaned the MAF sensor. I'll try again. I've used propane all over the engine trying to find a vacuum leak. I can't find one. I don't hear any hissing or sucking either. I put a vacuum gauge on a line and it shows ok.

I wonder if the O2 sensor can sometimes work and not work?

What would be the next step? Test the fuel pressure with a manual gauge? Why can't you trust the fuel pressure readings from the scanner? (or can you?)
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Old 07-02-2019, 09:27 AM   #19
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when I check the O2 sensors live with the scanner, sensor 1 bounces between 0.1V-0.8V. #2 is constant 0.7V and #3 is constant 0.8V
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Old 07-02-2019, 03:37 PM   #20
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Quote:
Originally Posted by Stangfire View Post
when I check the O2 sensors live with the scanner, sensor 1 bounces between 0.1V-0.8V. #2 is constant 0.7V and #3 is constant 0.8V
As I answered before:

A pre-cat O2 sensor should cycle (about once per 1-2 seconds) between 0.1 and 0.9 VDC.

A post cat O2 sensor should be steady between 0,.4 and 0.6 VDC. Ylou woudl indicate a rich mixture which may be for the same reason your RFP is high - its compensating (perhaps over compensating) for a lean condition.

Try resetting the PCM and see what that does. If the same try disconnecting the MAF (open loop) and see what happens to the RFP, ST/LT FTs, and post cat O2 voltages.

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