Test drive - more EMS light woes

After the extensive work done so far:- new timing belt, front brake discs, rocker box oil leak, oxygen sensor, coil pack No2, exhaust mid section, fuel filter, fuel filler cover and brake fluid change it is time to give it attest run. All is now well with the work done so far except the EMS light has returned.

The latest code to be thrown up is P0171 -  Generic System Too Lean(Bank 1). This has been reset a couple of times but keeps returning. Also the car is gutless could not pull the proverbial skin off a rice pudding. The warnings about this problem are all on the web and it cannot be run to Rome with this defect  without damage to the engine.

We have various bulb failure messages including one real one indicating  the offside front flasher bulb has failed. I had a brief look and it is a bu..er to get out.

Forum/google wisdom says (*)

Reported error on the Gendan code reader: P 0171 Generic System: Too Lean (Bank 1).

Freeze frame data for above

LT FTRM (%) - 22.6

* The short fuel trim is derived from the computer trying to keep the engine at a perfect 14 to 1 fuel gas air ratio. It uses the signal from the o2 sensor and the map sensor and the mass air flow sensor. to come up with long fuel trims and short fuel trims. The short fuel trim is what is happening right know. The long fuel trim is what is happening over a long period of time. The goal for driveability  is the long fuel trim to be within 10% of 0
MAP (in.hg) - 17.1
* Manifold Absolute Pressure
1 Bar = 29.4 in. vacuum at idle is always high and typically ranges from 16 to 20 inches Hg in most vehicles.
Engine (RPM) - 709
* Normal tick over type revs so MAP is ok
CALC load (%) - 37.2
* I guess at the point of failure the engine was under some sort of load
COOLANT TEMP - 189
* 189degF = 82deg C quite normal
ST FTRM1 (%) -3.1
* As per previous note this is actually within range so the oxygen sensor loop, MAP and MAF  must be doing something.
Fuel Sys1 - CL, using H02S
* Closed Loop = Good , using oxygen sensor = Good

In summary the long term fuel trim is in error 22.6% it should be less than 10%, at the point of failure (freeze frame data) the MAP(in.hg) absolute pressure was in range. Most of the forums indicate the MAF (Mass Air Flow) and MAP sensor sets the fuelling from the ECU to the injectors.

I have therefore ordered a MAF sensor as the most likely cause of the problem based on the data and reading the forums.

The other likely cause is a leak in the inlet manifold but I have checked that with a butane aerosol and I cannot find a leak (like I did on a previous car).

Acronyms

FUEL SYS1 – Fuel System 1
•CL – Closed Loop
•OL – Open Loop
•Using HO2S – Using Oxygen Sensor
•FUEL SYS2 – Fuel System 2
•COOLANT TEMP – Engine Coolant Temperature
•ST FTRM1 – Short Term Fuel Trim, Fuel System 1
•LT FTRM1 – Long Term Fuel Trim, Fuel System 1
•ST FTRM2 – Short Term Fuel Trim, Fuel System 2
•LT FTRM2 – Long Term Fuel Trim, Fuel System 2
•Engine (RPM) – Engine Speed in Revolutions Per Minute
•VEH SPEED (MPH) – Vehicle Speed in Miles Per Hour
•IGN ADV (DEG) – Ignition Advance in Degrees
•IAT (°F) – Intake Air Temperature in Degrees Farenheit
•MAF (lb/min) – Mass Airflow in Pounds Per Minute
•ABSLT TPS (%) – Absolute Throttle Position in Percent
•O2S11 (V), (%) – Oxygen Sensor 1 Bank 1 Voltage and Percent
•O2S12 (V), (%) – Oxygen Sensor 1 Bank 2 Voltage and Percent
•O2S21 (V), (%) – Oxygen Sensor 2 Bank 1 Voltage and Percent
•O2S22 (V), (%) – Oxygen Sensor 2 Bank 2 Voltage and Percent
•OBD2 Stat – OBDII Standard Vehicle Conforms To

Fuel filter

As the fuel filter looked original I think this needs changed (good old Arnold Clark service).

New filter in place

Exhaust

The exhaust is an issue on this car, the entre section is badly corroded and could pose a failure at the looming MoT test not to mention the 4K miles to Rome and back. We decided to change just the centre section to save cost. The tail section looks not too bad and hopefully will last till we get back from Rome. I found a source on ebay called ets a manufacturer in Poland amongst other places. The cost £26 + delivery £11.

Old parts taken off with the help of a plasma cutter

Joiner welded in place on one side for relability

New expansion box

Unfortunately is required a Klarius gasket at one end and a joining piece at the other.

Front brakes

As we are going down some alpine bends for a considerable time we decided to look at the brakes, the front ones in particular. Measuring the disc thickness revealed a 3mm deficit from OEM width. They were also ridged badly particularly on the back where only 50% of the pad width was contacting. I guess someone had changed the pads without changing the discs.

Old vs new

Nice shiny discs and pads

Timing belt

The timing belt had obviously not been changed. The surface of the belt had micro stress marks and was a funny dark brown shade. So we decided to err on the side of caution. The timing marks were not at all obvious and in fact the Haynes manual  did indicate this. All of the marks possibly except one appeared in the correct place. We decided to use what information we had and make a locking device to make sure the camshafts and crank shafts were unable to move during the process of changing the belt. The camshaft locking device was held in by a tie wrap just in case.

Marking everything just in case it all goes badly wrong!

 

 

Initial purchase faults etc

The car is a 2001 Volvo V70, 100K miles, 7 seater, automatic with large rear estate section ideal for R2R expedition. Angus and I found it on the bay of fleas and took a punt. Initially we found the car lacking in power when we test drove it but the engine appeared to be running very smoothly on tick over and had a good service history. However it had the EMS light on so I guess we knew it had problems and that is why we got it cheaply.

On return to Scotland we found it had a rather nasty looking oil leak and the EMS light returned on after resetting it.

The oil leak was coming from the camshaft inspection covers. It appears the Volvo has a positive pressure crankcase breathing system and the covers can leak on older cars. I put some fibre gaskets on the covers and we will monitor progress. The insulation on the cables to the coil packs are disintegrating another sign of age

The timing belt looks old (should have been changed at 90K and the brakes squeal and the disks have rather large lips.

I have a code reader called a Gendan which appears to be able to read the fault codes.

 

Time to order up a new coil pack and a O2 sensor.

Update 09/2/16

The O2 sensor and coil pack on No2 Cylinder was changed and the above dtc's went away after a reset of the ECU. Only time will tell if the dreaded EMS light remains off.

Update 14/03/16

The final tally was O2 sensor, coil pack and a MAF sensor. The EMS lamp now remains off. The live feedback from the ECU is non existent or unobtainable from that ECU hence the time it took to find the fault.