Monday, 31 August 2015

Trouble shooting Code P0172.. my EGR nut is loose

Just today my car threw a P0172 code

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Vehicle setup

Stock setup - Honda Stream RN6 - Compact MPV
Similar engine to some Honda Civic: R18A - 1.8 L Auto
Motor Oil:  Shell Helix 5w-40
Fuel: Caltex 92
Tire: Goodyear Triple Max, Pressure between 32 to 36 PSI
============================================

"System too rich (Bank 1)"
System Too Rich (Bank 1)

Read more at: http://www.obd-codes.com/p0172
Copyright OBD-Codes.com
System Too Rich (Bank 1)

Read more at: http://www.obd-codes.com/p0172
Copyright OBD-Codes.com
System Too Rich (Bank 1)

Read more at: http://www.obd-codes.com/p0172
Copyright OBD-Codes.com
System Too Rich (Bank 1)

Read more at: http://www.obd-codes.com/p0172
Copyright OBD-Codes.com
System Too Rich (Bank 1)

Read more at: http://www.obd-codes.com/p0172
Copyright OBD-Codes.com

It happened once a few months back.
I was mimicking the continental cars which had the engine switched off by the vehicle computer while it waited at the red lights. It automatically turned on again when the driver removes his feet from the brake pedal.

I think i flooded the system with fuel doing that. It threw a check engine lamp after a few repeatition of doing that on my vehicle.

Basically I erased the code via the OBD2 reader and the check engine lamp (CEL) went away.


Today is different.

The car had a jerk when the gear changed from 1st to 2nd.
I thought... its a transmission problem...oh no!

Then while i turned into my parking area, the engine switched itself off and the check engine lamp lit up on my dash.

I decided to drive on by restarting again and again.

It was quite worrying because the symptom would manifest only when the car stopped at red lights idling, but as soon as i am on the expressway, it didn't give me much trouble. I was worried because if the car switched itself off, i would loose the power steering and brakes. Thankfully the car pushed on.

I made it back to my workshop and did the troubleshooting immediately.

Its always good to have an OBD2 scanner handy to really know what happened.
Possible causes
a- Faulty front heated oxygen sensor
b- Ignition misfiring
c- Faulty fuel injectors
d- Exhaust gas leaks
e- Incorrect fuel pressure
f- Faulty Mass Air Flow (MAF) sensor

When is the code detected?
- Fuel injection system does not operate properly.
- The amount of mixture ratio compensation is too large. (The mixture ratio is too rich.)

Possible symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Excessive Fuel Consumption


Right now i am unable to remove the oxygen sensors  without tool. Yep, still waiting for it to arrive.


What I did
1. Cleaned the MAF sensor (item f)

2. Removed the fuel rail to check if it is leaky (item c).
I turned the key on several times without starting to prime the fuel pump and build the pressure up in the lines. The injectors did not leak.


No leaky fuel injectors

3. Inspect the spark plugs. Yes there is a bit of soot seen.



4. Check the EGR valve (item d)
I decided to check the EGR. I found the nuts slack. That could be the reason.

The 2 nuts on the EGR valve was slack

Well, i made my own gasket the last time. The material collapse from the heat which explained why the nuts securing it were slack. I made a new gasket and installed the EGR valve back again. This time i secured the nuts tight.


Road test
I took the car out again.
No problems this time.
I am glad it wasn't the injectors nor oxygen sensor.
They are costly items to replace!

After a long drive later, I took my spanner and tighten it again just to be safe.


Side note: It is not that the gasket is bad. It had a layered construction.
Perhaps i did not torque it enough the previous time.

Milam Mica PSS 150

This Klinger PSS150 is not al-cheapo material.
Milam laminates are suitable for use in hot, dry gas applications such as exhaust manifolds, turbines, turbo chargers and air heat exchangers.




Friday, 28 August 2015

Results after Air Fuel sensor cleaning

Results from cleaning Air-Fuel sensor

Update 29/Aug/2015: Final mileage 14 kpl vs 12 kpl

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Vehicle setup

Stock setup - Honda Stream RN6 - Compact MPV
Similar engine to some Honda Civic: R18A - 1.8 L Auto
Motor Oil:  Shell Helix 5w-40
Fuel: Caltex 92
Tire: Goodyear Triple Max, Pressure between 32 to 36 PSI
============================================

In the last post,  the Air-Fuel sensor had white deposits on its probe.

I had them cleaned. The mileage has improved tremendously.

You can find the previous article here:
http://eco-hondacar.blogspot.sg/2015/08/reversing-downward-trend-after-using.html


Expectation from cleaning AF sensor: If the fuel consumption does improve, then i can confidently say that the additive or dislodged deposits did clog up the sensor probe.

No doubt, the Redline Fuel System Cleaner does its job well at cleaning. However the sensor probe residual must be removed to restore the performance after usage of additives, even when label says it is sensor safe.

The reported mileage from the trip computer crept upwards, first from 11 kpl till 13.7 kpl (today).



I still have a bar left of fuel. Surpassing 632.4 km (Jun 29 record) for this tank should be fairly doable.

Hence, clearing the air-fuel sensor did yield positive results

It also meant that additive deposits can be removed from the sensors with success. 

Update


 There, a marked improvement after cleaning the Air-Fuel sensor.









http://www.fuelly.com/car/honda/stream/2008/ecohonda/336534

Now, i wonder if cleaning the oxygen sensor (it is located after the Catalytic converter) will yield significant results.


Friday, 21 August 2015

Reversing a downward trend, after using Redline Fuel System Cleaner

http://eco-hondacar.blogspot.sg/2015/08/reversing-downward-trend-after-using.html

I am looking for a solution. Why is my mileage looking poor?

============================================
Vehicle setup

Stock setup - Honda Stream RN6 - Compact MPV
Similar engine to some Honda Civic: R18A - 1.8 L Auto
Motor Oil:  Shell Helix 5w-40
Fuel: Caltex 92
Tire: Goodyear Triple Max, Pressure between 32 to 36 PSI
============================================

Since after using the Redline Fuel System cleaner, my mileage has been steadily performing poorly.

Track me at this link 

As mentioned (from my previous post), I suspect the build up deposits found at the upstream Air-Fuel sensor may have contributed to the poor mileage. Likely incorrect values were transmitted to the vehicle ECU and incorrect amount of fuel output is sent.

Side note - My tool gave way. Hence evaluation of the downstream sensor will be done after acquisition of a new socket removal arriving in a few weeks time.

The whitish residual is reportedly from the use of ADDITIVES. 


Aug 20, 2015
I have been off the Redline cleaner for 4 tanks now.


I am happy with the cleaning results but not in the department of fuel economy.
After 7 tanks later, i decided to crack open the Air-Fuel AF sensor (again) to clean.




Safety!! 
Always use safety equipment to protect yourself when handling heated / corrosive / oxidising agents


I took the AF sensor and dipped into strong acid for a few seconds each time and flushed well with water. Thereafter, shop air was used to dry the probe area. The acid removed the white residuals beautifully.

Feedback
Vinegar can be used from some forums i researched.
I tried deposit removal using a blow torch, but it is not a safe method. 
Photo of used sensors - Results after application of flame in attempt to remove deposits
This was experimented on my previous sensors.


Here is the (acid washed) sensor after 1 day of use.


A new coat of copper slip was placed onto the thread and installed, everytime.


The sensor was working, verified using the OBD scanner after the warm up, about 10 minutes into the drive.

The trip computer reported fuel consumption steadily improved starting at 11 kpl to 12.4 kpl after 30 minutes of driving 24+ km. On the second day, the trip computer reported an increase to 12.9 kpl

Cleaning one sensor at a time will reveal the impact of individual sensor and their effect to fuel economy.


Expectation from cleaning AF sensor: If the fuel consumption does improve, then i can confidently say that the additive or dislodged deposits did clog up the sensor probe.

No doubt, the Redline Fuel System Cleaner does its job well at cleaning. However the sensor probe residual must be removed to restore the performance after usage of additives, even when label says it is sensor safe.