Update on Emissions

Update on Emissions 1/9/15

Only investigations on Emissions and rich running done over the last month.

Idle Fault code:

Spent some time looking at 00533-10-10 Intermittent Idle Fault code.

Cleaned Idle Actuator Valve & Tested - The valve was dirty but operated fine. Found there was a set screw which allows air to bypass the throttle valve which must sets the minimum idle. This was about 10% of the opening. When the valve activates from the ECU its opens it further to increase idle.

This was before cleaning. After it was cleaned and retested with 12V. All functions fine. Refitted but added an extra clamp as the manifold pipe appeared a little loose.

Refitted and cleared fault code. Drove to and from work trying to get the idle to faultier. But as was fine when logging with VCDS But as soon as I thought it had gone away it came back.

Managed to capture some log files when the error code happens but seems to be about 20 or so times the revs go below 850rpm. Its hard to work out why the van has always had this issue since I bought it.

Manifold Air Leak Testing

Spent a few hours trying to look for air leaks in the manifold. Used Propane blow torch without lighting and a pipe attached to the end while moving around all pipework and manifold and no increase in idle revs was found. So suspect the intake system is pretty leak free (also indicated by vacuum gauge tests)

Unless the leak is around the brake servo pipe / connections I suspect there is no false air.

There is one thing that I find odd - When I block the main air filter intake by hand it does suck but the idle is not really affected. I am expecting that the engine should stall. 

This could indicate that some false air is getting from somewhere but I cannot find it. Will look again.

Canister Valve (N80)

It was suggested on a forum that I should check the operation of the Charcoal Canister valve & EVAP system. This valve adds petrol vapor when the engine is running and up to temperature. It has a major effect on rich running and if stuck open then can cause over rich mixture.

So I removed the canister valve N80 and checked its operation. You test by applying a vacuum on the manifold side and ensure its holds. Then operate with +12V supply and see if the vacuum is gone.

The valve operates correctly and holds vacuum. So its not this. Also thinking about it the EVAP vapor causes a massive swing in rich mixture the ECU and Lambda will complain if the valve is stuck open.

Still need to test if the ECU actually operates the valve but the VCDS log files say it opens during running.

Throttle Body & TPS Sensor

I was doing some checking on the specification from the workshop manual and comparing the data from VCDS. Everything else is within specification at hot idle except the following:

It seems that the specification suggests a throttle body butterfly angle of 5 Degrees and a Throttle Position Sensor Voltage of 0.3V when at Idle.

The ECU is reporting a angle of 6.7 Degrees and 0.3V when at rest. I am not sure how the ECU works out throttle valve angle as it is only measured by the TPS sensor. So either the valve is actually open or TPS is misaligned. Did not want to adjust the TPS as its sealed on its screws.

I did try adjusting the Throttle valve angle slightly. Adjusted to 6.0 Degrees and the TPS reads 0.28V so its also out of specification. Will need to think about this a little more. Its really hard to see if the valve is actually open as access is a problem.

I will investigate this further once I am confident it could be a cause of the Idle fault code and can actually see the throttle valve.

Reset to Default (ECU reboot)

So this I am not sure about. I have read that if you disconnect the battery for a while (around 30mins) the ECU will have reset and need to "learn" new settings.

So I took some VCDS logs before disconnecting the battery and when reconnected. Looking at fuel trims etc.

The van started fine and ran the same as before. Looking back at the data it did not seem to do anything.

Maybe this is a old wives tale. I will have to look at it again but I also read that the Bosch MP9 cannot be reset unless you have a MP9 Reset software which requires a dongled connection.

Spark Plugs / Long Journeys

So we went on a very long journeys over the summer. Trip to Anglesey Wales, this was a 400 Mile trip and then to Devon a 500 Mile round trip.

So the Van covered 900 Miles this summer! She ran well but is still drinking fuel. We filled up over twice as much as our friends driving a 1600cc Carburetor bay.

I though Fuel injection was more economical!

So after getting back from Devon the engine was sounding a little blowing from the exhaust. Could be the exhaust or suspect starting to loose valve seat or sealing.

So reset the tappets and removed the spark plugs from 1 & 2 as the right hand side was sounding more noisy.

Both plugs show the "normal" tan color but they also have some carbon. It does not look that rich as was expecting completely black. The black is kind of rough textured junk not pure carbon.

Cleaned off with wire brush. 

Next Steps

So the van is off the road at the moment due to wanting to get some rust / body work on the wheel arches (Post to follow)

Whats next?

So I am stumped again to what could be causing the rich & higher than fuel consumption.

Maybe I don't actually have rich mixture?

So the plan is:

1. Fuel Pressure Measurement - Measure Fuel pressure - This will confirm the Pump pressure, Fuel Regulator and also checks for leaking stuck injectors. I have the gauge and new filter and also the "special" fuel quick release clips to replace when removing fuel lines. Will also change fuel filter.

3. Catalytic Convertor - Need to check the CAT - I have managed to find a £300 UK cat replacement or a £70 Brazilian special. Might be worth removing the CAT and have a look inside for blockage / damage. Will also try the rag over the exhaust to look for leaks or false air in the exhaust.

4. More testing / Diagnostics - I am think about running a few tests with the lambda sensor outside and see if it changes the mixture when running. I am running out of things to look for now. Also scoping ECU connections and looking at the rich / lean signals when I remove things like the MAP sensor etc.

5. Gas Emissions Test - Might be worth another trip to the garage to get another CO emissions test to see if its still rich. Removes my doubt as its only the fuel consumption.

Here is the list of what I proposed to test last time:

1. Clear fault code from ECU (TPS zero offset) - Looked into & tried to fix
2. Test for blocked CAT - Block exhaust check Vacuum / Remove inspect
3. Measure CAT temperatures
4. Test Coolant Sensor - Resistance Vs Temp
5. Measure MAP Sensor Response - VCDS & Output Vs vacuum gauge
6. Fuel Pressure - Leaky / Stuck injector / Fuel Filter replace
7. Measure Lambda response
8. Test Charcoal valve - Power & Check - DONE

Really struggling and slowly loosing interest in solving this now.......

Issues, Emissions & MOT Failure

6/3/15 - Fail on MOT Emissions

Had yearly MOT today. FAILED! A few simple points like rear fog lights. On major failure was the emissions. CO % Fail and Lambda Fail. CO was 0.435% Lambda was 1.807 at Fast 2500-3000rpm

Initial thoughts where the Lambda sensor. Replaced Lambda sensor. Found the old one was very black with soot. Indicates Running Rich (as does the CO readings being well out) The problem is that the Lambda is showing it really lean.

Retested and still the same High CO and High Lambda. How can I have an engine which is Rich & Lean. Too much Fuel & Too much air!

8/3/15 - Retest

Anyway manged to get it through MOT after a long warm up and pressing the emissions test at the right place so I have a years ticket but still have issues. 

Still CO & Lambda where way over but  having a Fast at 4250-4850 rpm bought the levels down if we pressed the test button at the right time.

I have also noticed that the fuel consumption is higher & exhaust (lambda sensor & tail pipe have black soot)

Investigations / Cause:

OK so I have a number of things which can cause High CO and High Lambda:

Found this table:

(Legend: L = Low, H = High , M = Moderate)

CO	CO2	HC	O2	Possible Problems
H	L	H	H	Rich mixture with ignition misfire
H	L	H	L	Faulty thermostat or coolant sensor
L	L	L	H	Exhaust leak after the converter
L	H	L	H	Injector misfire, catalytic converter operating
H	L	ML	H	Rich mixture
H	H	H	H	Injector misfire, catalytic converter not working; combination of rich mixture and vacuum leak
L	L	H	H	Ignition misfire; lean condition; vacuum or air leak between air flow sensor and throttle body (false air)
L	H	L	L	Good combustion efficiency and catalytic converter action
L		L	L	All systems operating within tolerance; normal reading

The following table lists some of the results possible when the AFR (air-fuel ratio) is sustained at conditions ranging from too lean to too rich.

Conditions	Results
Too Lean	Poor engine power Misfiring at cruise speeds Burned valves Burned pistons Scored cylinders Spark knock or ping
Slightly Lean	High gas mileage Low exhaust emissions Reduced engine power Slight tendency to knock or ping
Stoichiometric	Best all-around performance
Slightly Rich	Maximum engine power Higher emissions Higher fuel consumption Lower tendency to knock or ping
Too Rich	Poor fuel mileage Misfiring Increased air pollution Oil contamination Black exhaust

So from this information I think it could be the following:

1. Fault Code on ECU
2. CAT Not working 
3. Exhaust Blockage / Restricted / Leaking 
4. MAP Sensor
5. Coolant Sensor (Oil Temperature)
6. Dirty Injectors / Stuck Fuel Injector
7. Fuel Pressure Regulator / Too High Fuel Pressure
8. Blocked Air filter
9. Faulty Lambda Sensor
10. Faulty PCV Breather
11. Tappet Adjustment
12. Faulty Charcoal Valve

So in order to diagnose I thought I would take my time and not rush out and buy expensive parts. I have done the following investigations.

1. Fault Code on ECU - Check ECU and only one fault code which my van has had ever since I purchased it - Throttle Valve position - I think this is just the Zero setting for throttle body when installed. I ran VCDS and logged the data and compared it with a log I ran a year before. Could not see any differences.

Still to test - 
Find out how to reset throttle position to clear fault code for ever. Need to get the correct process in VCDS and try setting.

2. CAT Not working

Could be a blocked or non functioning Catalytic convertor - These are £600 to £469 which is the cheapest in the UK. They ONLY COST £60 in Brazil!

My main concern in replacing the CAT is that the Lambda sesnor was covered with soot & carbon so unless its blocked (causing blow back) it is rich from the engine pre-cat as the lambda is the last sensor. CAT function is hard to test.

Still to test - 
Measure CAT function - Temp before and after CAT.

3. Exhaust Blockage / Restricted / Leaking

A block or restricted exhaust causes issues. It basically causes the exhaust to recirculate in the combustion and even inlet manifolds. This could be the cause but ran a vacuum test on the inlet (common and useful technique for Air leaks and back pressure) this showed a typical "normal" response.

Leaking exhaust can cause issues but I cannot find any leaks or holes. Exhaust is expensive to replace so will leave this until later. 

Still to test - 
Will try the rag up the exhaust to see if it stalls and what it looks like with a restricted exhaust.

Will remove CAT & Both boxes and have a look for blockages. Need to order gaskets, new bolts & exhaust sealant

4. MAP Sensor

MAP sensor is the prime sensor for the amount of fuel to inject into the engine. If it was reading an incorrect level it "could" be the reason to run too rich. No fault codes so in range but could be giving a false reading.

I don't have the VCDS version with MAP pressure readings but plan to check against gauge.

I have been looking for the MAP sensor. Parts from Bosch are typically around £100 so not going replace this unless I am sure.

Still to test -
Measure pressure with gauge and check MAP output voltage with voltmeter.

Purchase VCDS to get access to Measurement blocks 0000 which has MAP pressure readings

5. Coolant Sensor (Oil Temperature)

The engine runs rich until up to temperature. So if faulty will constant run in open loop and rich.

Checked with Multimeter and also Logged data with VCDS and its seems to be correct values and heats up to switch to closed loop once warm. No fault codes. So not coolant sensor at fault.

One thing to note is that the oil temp takes ages to switch to closed loop (approx 80oC) short journeys could be causing to run rich for ages. I am sure the hotter climate in Brazil it does not take so long. On UK days takes a far few miles to get to 80oC.

Still to test -
Check coolant vs temp response. 

Maybe include an extra resistance to make value read 10oC hotter so goes into closed loop earlier (great for shorter journeys)

6. Dirty Injectors / Stuck Fuel Injector

If an injector gets stuck on. The engine will over fuel and run rich. The engine will sense this at lambda and I would expect the on pulse duration to be very short as the engine tries to lean out. I did not see this on the VCDS logs.

Used carb cleaner on inlet throttle body and down to injectors. Also added a bottle of Redex injector cleaner.

Still to Test - 
Test using a fuel pressure gauge (should stay at pressure for long time when pump is off - leaky injector will cause rapid pressure decay) need to restrict fuel back to pump

To test I will need to check the spray pattern (remove and spray into a jar)

7. Fuel Pressure Regulator / Too High Fuel Pressure

If the fuel pressure is too great (pump) or faulty fuel pressure regulator causing too higher pressure. This will cause the injector to over fuel so the ECU thinks its pulsed the correct amount but mixture is too rich so will back off pulse duration to lean out mixture.

I have check the pulse widths from a good emissions run done last year and after emissions failure and they seem the same nothing indicates an issue. However I have been reading about short term and long term trims. This should show if its and issue BUT I cannot find them in the VCDS log.

Checked the vacuum line to the pressure regulator for fuel (indicates a leaking regulator seal) and found none so suspect its good

Still to Test - 
Test using a fuel pressure gauge not sure what the actual fuel pressure should be but expect regulator should return pressure back to fuel tank.

Replace fuel filter and see if its causing a higher pressure. Blocked filter will cause higher pressure but reduced flow.

8. Blocked Air filter

Block air filter will cause lack of air and therefore rich mixture. Inspected the air filter and looks clean.

Still to Test - 
Will replace air filter as part of next service

9. Faulty Lambda Sensor

Faulty Lambda sensor will cause over or under fueling. The ECU should report a fault code if lambda is at fault.Replaced the Lambda sensor anyway, so its not the sensor.

Still to Test - 
Will check with scope the Lambda signal and see if the ECU is getting a lean or rich mixture from its voltage response.

10. Faulty PCV Breather

I have noticed from the HC levels of zero this could indicate a blocked or non functional crankcase breather valve.

I have noticed before that the breather does not seem to be working and pipes are always blocked with the "gunk" " Mayonnaise" from the oil / water mix. This is common place with air cooled engines and short journeys never burning off the water.

I have no managed to source a new PCV valve (211 129 101) took me ages to find one finally got one from The Netherlands.

When fitting it I noticed that all the other Brazilian engines had the breather fitted vertically. Mine was always fitted horizontally and therefore incorrect.

Now fitted a new one the right way round! Not much difference but I am sure its better and working now. Not sure what effect it will have on emissions.

11. Tappet Adjustment

The tappets will have an effect on emissions. So reset and they did not make any difference to emissions.

12. Charcoal Valve

The engine uses the fuel tank breather re-circulation via a charcoal canister and valve. This then adds an extra breather fuel back to be burnt. This is regulated via the ECU once the engine is warmed up.

This could cause an extra over fueling and rich mixture if always on. The VCDS logs show that this is functioning BUT a faulty valve could cause this to be always on but this should be measured at Lambda sensor and adjusted for

Still to Test - 
Test the canister valve to see if it functions on demand.

So in summary I have done the following:

1. New Lambda Sensor 
2. Carb Cleaner / Redex
3. New & correct fitting PCV Valve
4. Replaced Vacuum hoses 
5. Measured Inlet Manifold Vacuum - Looks normal no leak or restriction
6. Tappet Adjustment
7. Measured coolant, throttle, injector, valves etc nominal resistance - All within specifications

I have to do the following:

1. Clear fault code from ECU (TPS zero offset)
2. Test for blocked CAT - Block exhaust check Vacuum / Remove inspect
3. Measure CAT temperatures
4. Test Coolant Sensor - Resistance Vs Temp
5. Measure MAP Sensor Response - VCDS & Output Vs vacuum gauge
6. Fuel Pressure - Leaky / Stuck injector / Fuel Filter replace
7. Measure Lambda response
8. Test Charcoal valve - Power & Check