OBD II Shop - Engine Builder Magazine


Having come from the era of the muscle car, it is extremely interesting to me to get out and look at the new vehicles, feel the performance and see the technology that makes the tailpipe emissions half of what they were in 1996. This technology is made possible by faster power train control modules that network to the rest of the body control computers to know exactly what the energy needs are to keep the passengers comfortable. At the same time information is sent from the customer demand circuit (throttle pedal) on the desired acceleration imput and from the steering wheel for vehicle stability and, oh by the way, the tail emissions are kept within regulation.

So when you see one of these 5,000 lb SUVs cruising down the road, you might be able to rationalize its $50,000 window sticker. Even more interesting now are the mechanisms in place for the consumer to purchase this vehicle. The discounts and financing packages are all tools of the auto manufacturer to bring in cash flow. I’ve been fascinated to see $50,000 vehicles discounted to $40,000 and then no more than a couple months or even weeks later that same discounted vehicle discount dropping another $5,000. What happened to the poor guy who bought his vehicle at $40,000, took a 10 percent hit because he drove it off the lot and then found that the manufacturer was willing to discount it even further?

The next dynamic that enters this equation for the consumer is how does he insure his risk if the expensive auto is stolen or totaled to keep him financially solvent? To the rescue is the insurance company with “gap insurance” policies that will cover the consumer on the difference between actual value of the vehicle and the finance value.

This protects the consumer on physical damage and of course, the assumption is that the OE warranty will protect him in case of mechanical catastrophe. But what happens when the dealer or manufacturer determines the mechanical failure is because of abuse or lack of maintenance?

If you haven’t been yet, it’s likely you’ll soon be visited by an over-leveraged consumer. He’ll figure the cheapest way to get his vehicle running will be you. Traditionally, this may have been true; however, OBD technology has caused casting and components to change faster than our aftermarket industry can stay abreast of. Lately we have been obliged to go back to the OE supplier, leaving us very little margin for price.

The potential downside on replacing with original parts is whether the engine is truly original – or was other equipment added to the vehicle? Could that engine benefit from a replacement component of a better design?

With this understanding of some of our industry’s limitations, we must wear our detective, engineering and sales hats. Let me give you an example of how all three need to work together.

When inspecting a low-mileage engine, we found that the ring land of the piston was broken and portions of the piston were embedded in the cylinder head. The simple solution looked like a replacement of a specially made piston with thicker lands and better material quality. However, after selling the appropriate upgrades, we saw the same customer a month later. This time the piston did not break apart (thanks to superior material design), but we did find streaks of molten aluminum that had deposited on the cylinder wall and piston. This was considered premature by the customer and thought to be a warrantable repair for him.

Eager to help solve his problems, I had to put my detective hat on. We looked over the entire vehicle, finding such things as a new air inlet hose on a 12,000-mile vehicle. There were mysterious holes in the core support area similar to those used by a solenoid. I also learned that the customer must have experienced flooding in his trunk because he had holes drilled in the floor pan to let out the water – or maybe to mount a nitrous bottle.

Playing detective is only part of the job. You have to not only show the customer that you know the cause of the failure but get his acceptance of responsibility for the failure. The resolution of this experience may be repeating the adventure a second time with better parts or the correct parts for the system that caused the failure; it can be restoration back to stock; or it may be as drastic as walking away from or “firing” your customer.

The firing of the customer can sometimes be the most difficult. Remember, you may be dealing with an over-leveraged individual who paid for his repairs with a credit card. If it is still within a 60-day window, he can go to his credit card provider and tell them a story, which puts you in poor light even though it is a lie. It then becomes your responsibility to defend yourself so that you don’t get a chargeback.

The incentive for the credit card company is to keep their customers paying them without defaulting on the entire bill. Their resolution is reasonably swift to get the balances back into their favor. Remember this can happen to you even though you have signed invoices, a signed credit card receipt, and the customer was there and witnessed the repair. I know: it happened to me.

When trying to resolve the problem, you’re not necessarily alone. You have the OBD system working with you to help you protect this power train and catalytic converter. This is a powerful partner if you know the recommended parts to be installed and the modifications that you are dealing with.

Sometimes the kit that a customer buys has been assembled for price and not for application. This requires you to track down component part numbers, cross-referencing with the vehicle manufacturer to see if the fit matches the application.

In this particular case we needed to know the volume and pressure delivery of the fuel pump; the injector size in pounds-per-hour, not cc’s of delivery; the spray pattern of injector; and whether it was a high impedance or low impedance injector. This helped us verify the parts involved.

Next, put your engineering hat on to look at the installation. Was the timing set correctly for the added product? Were the throttle position sensors installed and adjusted correctly?

In a case such as this, was there a long enough length of nitrous hose between the intake manifold and the solenoid? You see, if nitrous is ingested before you match fuel delivery, the response in the combustion chamber will be faster than any of the associated sensors can protect themselves (detonation sensor, oxygen sensor, etc). This system is designed for normal combustion events that make them look passive when used with an oxidizer such as nitrous oxide. Such a scenario will not cause an immediate part failure, but it is like tapping an egg with a hammer – failure is imminent!

This is where adding two to three feet of line between the nitrous solenoid and the discharge nozzle buys you enough of a delay for the engine to experience both nitrous and fuel arriving together, giving the cylinders a balanced blend. This balance allows the control system to see a smooth transition and not overcorrect with timing or

Problem solved? Not exactly. Was the top ring land of the chosen piston moved down from the top of the piston to protect it from the high temperature extremes? Piston-to-wall-clearance can also be an issue if nitrous is used long enough to cause growth beyond the clearances you installed. These tolerances can be assessed by dealing with a piston manufacturer who has nitrous experience. While these specifications may work fine with the piston, will they work with the OBD system? Too loose can cause the detonation sensors to see a higher level of noise and may tune out spark knock when the computer should be removing timing under normal operation.

When solving these engineering challenges, don’t forget to be compensated. The salesman who sold your customer his parts is being paid and generally accepts no liability. You being the service professional are held to a higher level of scrutiny and may have to use disclaimers to protect yourself for the use of non-stock parts and the non-OE specifications used to install these parts. A disclaimer document should be considered as your gap insurance and should be presented to the customer before or during the job transaction.

Not all vehicles carry the same baggage of what I just described, but as an industry we need to understand more of OBD system operations. The tools that we need to make us competitive are good technical information on a system, detailed engine specs of the OE design, a network of parts manufacturers that have good technical assistants, and management and technicians willing to learn on the fly. The rewards are not only financial, but personal: you’ll have a lot of pride when seeing a performance improvement and a customer who will brag about his experience with you.

Norm Brandes owns and operates Westech Automotive, Inc., a machine shop and vehicle repair service business located in Silver Lake, WI.
[email protected]

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