Autocar test shows worse economy after Volkswagen diesel fix
Autocar test shows worse economy after Volkswagen diesel fix
An Autocar test has exposed that the fix Volkswagen is applying to diesel-powered cars fitted with its emission-cheating software can have an adverse influence on fuel economy in the real world.
VW fitted more than 1.Two million cars sold in the UK with software that permitted the car to know when it was undergoing emissions tests in order for its NOx emissions to reach legal levels. It is now having to apply a technical fix to all affected cars and has done so to more than 600,000 at present.
The Autocar test was conducted at Millbrook Proving Ground to the standard set by the True MPG real-world test cycle of our sister title What Car?. The test used the latest international standard equipment for testing vehicles in a scientific and repeatable manner to industry standards.
Comment: what does our VW dieselgate fix test prove?
It exposed that while NOx emissions were almost halved from 0.639g/km pre-fix to 0.351g/km post-fix, our test car’s combined fuel economy had fallen from 50.72mpg to 47.61mpg. This means that its CO2 emissions enlargened from 147.3g/km to 156.9g/km, a switch of 6.5%.
The car we tested belonged to reader Jonathan Mudd and was a two thousand thirteen Volkswagen Touran fitted with the EA189 1.6-litre diesel engine, one of three units sold in the UK by VW fitted with the cheat software that needs correcting.
© Autocar Autocar’s test was carried out at Millbrook Proving Ground The economy drop is at odds with VW’s insistence that its technical fix has no influence on a car’s spectacle or economy. VW’s claim is based on back-to-back NEDC tests — the lab-based test cycle by which VW is being measured by the authorities — and has been verified by the KBA, Germany’s motor vehicle regulatory assets.
Upon completion of his car’s technical fix, which took five hours, Mudd was introduced with a ‘Certificate of Completion’ that stated: “The successful implementation of the measures does not adversely influence the engine spectacle, fuel consumption, CO2 emissions, torque or noise of your vehicle.”
On that point, Mudd said: “Looking at the pre and post-fix test data for fuel economy, it’s concerning that the data doesn’t back that claim up. My car is now less fuel-efficient than it was before the required technical measure was carried out and means I’ll be out of pocket as a result.”
Our Millbrook test assures repeatability of the economy and CO2 figures to within 1% on any subsequent tests and is typically accurate to within 0.5%, so the margin of error is not enough to account for the Trio.11mpg drop in economy.
Results for NOx emissions are less reliable from one test, however, and are best recorded as an average of three tests. That is why Autocar is only focusing on the influence the fix has had on fuel economy.
VW disputes our findings. It says there are more than twenty variables that can influence a test result such as ours. It would not, however, provide further details of those variables when asked to do so by Autocar.
In total, three engines are being immovable in the UK by VW: 1.Two, 1.6 and Two.0 versions of the EA189 engine. The number of different combinations of car, transmission, engine and so on comes to 750, meaning VW needed to come up with seven hundred fifty different fixes.
© Autocar Jonathan Mudd described the test results as “concerning” It is understood that the fix to the Two.0-litre diesel models is the most sophisticated.
Our test focused on the influence on real-world economy of the fix that VW has applied to the engines, but the Two.0-litre engine type is also subject to a growing number of case studies and reports that the fix is causing breakdowns in cars that have had it done.
A report by the Volkswagen Diesel Customer Forum (VDCF) last month said owners of postfix VWs with the Two.0-litre diesel had experienced breakdowns, enhanced fuel consumption, diminished spectacle, enhanced harass smoke, excessive regeneration of diesel particulate filters (DPFs) and DPF failure.
Harass gas regeneration (EGR) valves, turbochargers and fuel injectors are also said to have failed and others report their cars having entered limphome mode or their engines having become noisier.
VW claims many of these faults could be down to poor maintenance, with some of the cars even missing their DPFs. None of the issues is related to the fix, VW asserts.
VW hopes to have the fixes finished to all 1.2m by the autumn. The German manufacturer says less than 1% of owners have so far reported problems after the fix, which translates to around six thousand customers.
In a statement, Volkswagen said: “Far fewer than 1% of UK customers who own affected Volkswagen Group vehicles that have received the technical measures have reported any issues.
“That means that more than 99% of customers are sated with the application of technical measures, which of course are carried out free of charge. We make it a priority to look at the vehicles of the very puny proportion of customers who report any issues.”
The VDCF claims the number of complaints and cars affected by the fix is actually much greater and that VW has not kept a log of complaints. The VDCF has urged the government to consider prosecuting VW.
A class act case being built against Volkswagen is gathering data in a survey of owners in the UK claiming their cars have been affected by the diesel engine fix.
In an email sent to those seeking class activity by one of the law firms, Harcus Sinclair UK, it was claimed that of the seven thousand five hundred four survey respondents who had had the fix carried out on their car, three thousand nine hundred twenty five have subsequently experienced a problem with their vehicle. Of those, two thousand one hundred three have experienced diminished fuel efficiency, five hundred twenty six have had their car come in limphome mode, and two hundred claim to have been told by a garage that their fault is related to the fix.
Volkswagen’s response to our test
“Volkswagen was not provided with sufficient information concerning the testing criteria nor an explanation of how such a cycle is representative of real-world driving.
“Volkswagen also notes that comparative fuel consumption measurements must be carried out very meticulously with, among other things, due attention to cycle profile, duration, the type of test equipment and settings (including aerodynamic resistances, coast down data and blast adjustments), the system used for the measurement and the scatter of test numbers.
“To attain a level of consistency, one measurement is not sufficient and more measurements must be ended on an identical vehicle. Further, as Autocar is aware, in any standard comparative analysis, comprehensive vehicle prep would always be critical to the reliability of the values.
“It should also be noted that the relevant approval authorities have approved the technical measures and that during the development of the technical measures, Volkswagen worked with care to ensure that fuel consumption figures in the homologation cycle and on the road remain the same when compared with the previous software. If increases in fuel consumption were detected during the development phase, the software was revised and retested.”
– Despite VW’s claim, Autocar supplied all test details requested by the manufacturer.
© Autocar Autocar’s test was carried out at Millbrook Proving Ground
How the What Car? True MPG test is carried out
The test is conducted on a rolling road under stringently managed lab conditions. This means the test is repeatable, because outside variables such as weather and traffic don’t affect the results.
The test is carried out at Millbrook Proving Ground, a centre used for regulatory approved vehicle emissions testing. Millbrook has the latest equipment for testing vehicles in a very scientific and repeatable manner.
Very first, we inspect the car to check its roadworthiness. We then weigh the car, and that weight is used to calculate the rolling road (or dyno) fountains that replicate the resistive compels acting on a car when it’s being driven on the road.
Next, the tyre pressures are checked and an harass connection is fitted, permitting the car’s emissions to be measured. We also carry out an harass pressure check to identify any leaks.
The climate control is turned on and set to 21deg C. Headlights are switched off during testing. Any other electrical equipment — for example, stereo or heated seats — is also switched off.
Next, we carry out a pre-conditioning test on the car. This is, in effect, a dress rehearsal, to check that there are no problems and to make sure that all the cars we test are in the same state before they commence the True MPG test.
We leave the car to ‘soak’ at 23deg C so that every car starts the test with the same engine temperature. We don’t place the car’s battery on charge while this is going on.
Then it’s time for the True MPG test. We sample the tailpipe emissions — carbon dioxide (CO2), nitrogen oxides (NOx), carbon monoxide (CO) and unburnt hydrocarbons (HC) — on a second-by-second basis and collect bagged samples of each phase of the test for our calculations.
Our results are summarised by different phases of driving — town, motorway and rural — and fuel economy figures are calculated from CO2 results. Ultimately, our headline True MPG average is calculated.
The post-fix problem: how one reader’s Golf has serious issues following its fix
Hampshire-based reader Richard Framework had his Volkswagen Golf 1.6 TDI’s fix ended in January.
The next day, Frame’s car began to judder in low gears, and the fan went into overdrive when the engine was turned off. He took the advice of the local VW garage and drove it at above 45mph in fourth gear for fifteen minutes, in a bid to regenerate the diesel particulate filter (DPF).
Nine days after the fix, the car wouldn’t embark, so Framework returned it to the VW garage.
Three days later, he was told the car needed a fresh harass gas regeneration (EGR) valve. VW eventually agreed to cover the cost (about £1300) but wouldn’t say this failure was in any way linked to the emissions fix.
© Autocar Reader Richard Framework has had serious problems with his Golf following the fix This procedure took a week, at which point Framework was informed that the garage had found a faulty injector. VW also agreed to pay the total cost for this (about £700).
When Framework collected his repaired car in mid-February, he still noticed a significant difference. In early March, VW recalled Frame’s car because the EGR valve had been fitted with the wrong bolts. He voiced his concern about the Golf still sounding very different and juddering after it had been commenced. VW checked the other injectors but determined that none of them was faulty.
Since then, Framework said he has repeatedly experienced strong searing smells from the engine after brief journeys and the fan runs rapidly to cool the engine.
He said: “Since the fix, the engine needs to regenerate so much more — on average, once every two weeks — which means that fuel efficiency has also been affected.”
Framework contacted VW on twenty March about the ongoing issues with his Golf and was told a case manager would call him back. At the time of Autocar going to print, he had still not received that call. He said: “Before the NOx emissions service act was applied, my wifey and I had been very glad with the car and with its spectacle.
“Now, the car sounds like a van and smells like a lorry. Volkswagen has picked up the bill so far but at no point has it accepted there is a link inbetween these extra problems and the emissions fix, when I believe this is the visible cause.
“We have now lost all faith in how reliable our car is — and each and every time we drive it, we’re genuinely worried that something else will go wrong. This is our only car and we have a youthful family.”
Related: It’s not just VW – thirty dirty diesels accused of emissions cheating
It’s not just VW: thirty dirty diesels accused of emissions cheating
