Auto Service World
Feature   February 1, 2005   by Auto Service World

Countertalk: Audit Unearths Emissions Repair Troubles

Nearly half of the repairs made to vehicles under Ontario's Drive Clean emissions testing program made them worse. Who's at fault?

When Ontario’s auditor took a look at the province’s Drive Clean emissions testing program, what he sought to highlight was waste and questionable practices. What he found was far more disturbing to the aftermarket.

Yes, the auditor’s report did fill the newspapers with some troubling details in early December. The report identified 3,200 uniquely numbered emissions certificates that were presented for license plate renewal more than five times each. One uniquely numbered certificate had been presented more than 400 times for different vehicles, pointing to the need to tighten controls.

It also discovered some waste. Even though the program generated more than $30 million for the province’s coffers, the audit says that this chronic system of waste and lack of controls, the result of sloppy procedures in the least and possible fraud at the worst, cost the program some $600,000.

In addition, allowing shops to conduct offline testing resulted in the fact that some 40,000 vehicles were presented with license plate renewals even though Drive Clean certificates for those vehicles were not in the system. It certainly got the attention of the press, the public and, of course, the ministry’s Drive Clean office.

“We know there are circumstances that permitted it,” says Drive Clean spokesman Charles Ross. “Fundamentally the system allowed for an override, because duplicates were being issued.” Ross explains that some emissions testing hardware reset the numbers when they had to be rebooted, but there are still some 137 cases being investigated by the Drive Clean enforcement issue.

“[This problem] was identified quite a while before the audit,” he adds, saying also that adjustments have been made to the licensing office computer system to eliminate this override.

For the trade, however, many of these are procedural issues. The fact that cars were licensed without a certificate showing up in the system is a problem of bureaucrats and the companies that are contracted to run the licensing offices. Offline testing is a computer issue. Even cases of fraud can be dismissed as a problem restricted to a small minority.

One assertion that the industry can not so easily shake, and which points to problems in Ontario and elsewhere in the country, is that so many of the repairs conducted under the program did not pass muster.

The auditor’s report, in fact, showed evidence of the problem, summarized in one short phrase: “We reviewed a sample of 2002/03 emission certificates for vehicles that had been given a conditional pass after repairs were done and found that almost half of these vehicles produced greater emission readings than before the repairs were performed.”

According to technical specialists, the reasons why this occurs involve issues of repair cost limit–a maximum of $450–and a chronic misunderstanding of the chemistry of combustion.

Mark Theriot, managing director, Global Service Technologies, Delphi Product & Service Solutions, says that it can be a complex issue.

“The answer to this question, in my opinion, is a mixing of several key issues that blend together, resulting in an overall lower success rate. Techs are creatures of habit and they will tend to play the odds, especially when they do not have the correct information to choose otherwise. They will take the high probability route to repair which is replacement of the common components.”

Spark plugs and wires are perennially at the top of the list of components judged at fault during a failure, but may not always be the real culprits.

High emissions can just as easily be the result of a malfunctioning EGR valve, an oxygen sensor, or something more insidious.

“Techs will tend to jump right to the component when, in actuality, a dirty connector or vehicle ground could just as easily be the culprit.”

Conversations with technicians in the field also reveal the fact that the repair cost limit might squeeze the technician into a non-repair repair: if the repair is a $750 EGR valve, but the repair cost limit is $450, he feels he has to do something.

Plus, there is the complex issue of whether combustion chamber cleaning fluids are causing high hydrocarbon readings on retest, and whether much care is being taken to warm the vehicle properly on retesting as it has to receive a conditional pass certificate regardless of what the test numbers say.

Regardless of whether a vehicle is subject to a mandatory emissions testing program, vehicle systems do degrade. What the testing program does reveal is that in many cases, regular maintenance is not high up on the priority list.

“In fact, we have done extensive analysis on the market,” says Chris Harrison, product manager, NGK Spark Plugs Canada Ltd. “Our data findings, which were corroborated by DesRosiers Automotive Research, were that the repairs are being done much later than the recommended intervals, both by the OEM’s recommendation and for the lifespan of the component.

“The problem with oxygen sensors is that they are not a very commonly understood product. It is still very early in the lifecycle of the product and they’re just not being replaced when they should be.”

Harrison says that only when there is a severe driveability problem does the component get attention. Even so, while the life expectancy for oxygen sensors should see a gradual increase in replacement rates over time, starting at about five years, there is a low to moderate incidence of repair in five- to eight-year-old vehicles, then a significant increase for those vehicles older than eight.

“The bottom line is that they aren’t being replaced when they should be,” says Harrison.

Of course, simply throwing an oxygen sensor at a problem isn’t the solution either.

“The other large part of it is looking at one element and replacing it piecemeal. If you are replacing the oxygen sensor, and there is a fuel trim strategy problem, the oxygen sensor will try to lean out the mixture, but regardless of what signal it is sending back, it won’t correct that situation.

“I would suspect that it is a question of not looking at the entire engine management and other tune-up items that is the problem.”

What is clear is that technicians aren’t employing proper diagnostics to determine the real cause of the problem. What is also clear is that the issue is a complex one.

“Last year we funded a test by Sierra Research in California on five OBD II vehicles with original oxygen sensors and about 100,000 miles,” says Dave Pankonin, senior product manager, Automotive Aftermarket.

The test was designed to see what, if any, effect oxygen sensor maintenance would have.

All vehicles passed the California emissions test, and were tested again with the original sensors, one sensor completely disabled (unplugged), and all sensors replaced with new OE sensors. “Our objective was to see if, as in OBD I vehicles, fuel mileage would improve if old oxygen sensors were replaced with new ones,” says Pankonin. In OBD I tests, fuel mileage improved by about 10%. In the OBD II test, there was a slight improvement in the overall fleet mileage, but most of the improvement was from one of the five vehicles.

“The interesting thing that we saw was that results varied widely. In one case, mileage actually improved with oxygen sensors disabled!”

For those cars being repaired under Drive Clean rules, it would appear to point to more than just the effect of new components–more specifically, whether the right components were being replaced.

“Perhaps it is because of an ageing technician population, and emissions testing for that matter is still very young in the grand scheme of things,” says Harrison. “I believe that is partly the issue, and it may be a cost issue on what the consumer wants to get away with, depending on the age of the vehicle.”

“Correct diagnosis may be the biggest challenge,” says Pankonin. “If an oxygen sensor is replaced for a high NOx condition, it is likely that the NOx emissions will get worse because the sensor is working more efficiently to drive the ECU to lean.”

It is a complicated issue to be sure.

One technician asserted that the poor performance on retesting might be partly that the repair cost limit has a shop owner thinking that each failure means a sale of up to $450 in parts and labour, and he proceeds to act on this assumption even though an effective repair might cost more (such as a $750 EGR valve required to fix a NOx condition).

“The only answer is to fully repair the cars,” says Drive Clean’s Ross. “The repair cost limit is not the answer.”

The Drive Clean program is currently under review and many of these issues will be dealt with. The emissions limits have already been tightened, but many aspects of the program could be adjusted: testing technology, air quality issues, advances in fuels, and what other programs are doing.

For the aftermarket, though, questions will continue to be raised as long as repair procedures fail to improve vehicle emissions.


Combustion Science

There are five basic components in vehicle exhaust. These can direct a technician to some basic problem areas, though not necessarily the root cause.

* HC: Unburned Gasoline

* CO: Partially Burned Gasoline

* CO2: Completely Burned Gasoline

* O2: Oxygen

* NOx: Oxides of Nitrogen.

In very basic terms, here is what an exhaust failure mode can tell you:

* High HC: misfire or bad burn

* High CO: too rich

* High CO2: poor engine efficiency

* High O2: too lean or just air

* High NOx: too hot or too lean

Often high HC and high CO will be seen together, as they both point to incomplete combustion.

Of these, however, rectifying NOx emissions seems to provide the most difficulty to many technicians. It can be the result of many factors.

When an EGR isn’t flowing, the combustion chamber gets hotter and creates more NOx. Extra carbon causes more pressure in the chamber, which causes more heat, which leads to the formation of more NOx. An engine that overheats will do the same thing.

Unless the wrong heat range of spark plug is installed, rarely will replacing plugs and wires solve a NOx problem. An ignition misfire will create much less heat, and therefore much less NOx.

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