Magnaflow Catalytic Converter Quality:

Compare MagnaFlow's catalytic converters with any other manufacturer and you'll see why MagnaFlow has become a leader in the manufacturing of exhaust components. Others may employ one or two of the following features, but only MagnaFlow puts them all together to create a catalytic converter that exceeds basic need and function. Our years of research and development have resulted in many unique features that are exclusive to MagnaFlow. We combine efficient manufacturing techniques and state-of-the-art industrial design to produce an end process and product that sets, rather than meets, the highest standards of product performance and efficiency in the industry.

Magnaflow - Catalytic Converter Quality

1. MagnaFlow converters have a ribbed body that minimizes expansion and distortion when the converter heats up. The ribs form a channel that protects the cushioning mat from direct exposure to exhaust gasses and they hold the ceramic catalyst in proper alignment.
2. MagnaFlow converters have a 1/2" lap-joint where the necks meet the body. The neck does not extend into the converter body where it could hamper exhaust flow. This is the strongest and smoothest flowing inlet/outlet joint of any manufacturer.
3. We maintain separate dies on different sized inlets. We don't skimp by putting larger neck sizes on smaller bodies. This would reduce the flow of the converter and reduce the quality of our product.
4. MagnaFlow uses a monolithic honeycomb catalyst. The ceramic is designed for maximum flow and surface area. The coating method is strictly controlled to maintain exact specifications. An improper coating could result in flow restrictions or an emission test failure.
5. MagnaFlow uses a heavier gauge stainless steel, tip to tip. Others use mixed weights and materials.
6. MagnaFlow converters are seam welded close to the converter body for a strong, tight bond. We don't weld along the edge which could allow the converter to expand like the folds in an accordion, allowing the catalyst to move around.
7. MagnaFlow installs a factory capped, 90 degree air tube on "with air" converters. This saves time during installation. There is no need for additional labor to weld on an air tube or to create a bend when only an air tube stub is provided.
8. MagnaFlow uses an aluminized or stainless OEM-style ribbed heat shield that creates a rigid wall of protection against heat and adds to the structural stability of the converter.

Clean Parts - MagnaFlow de-greases and washes all fabricated components after assembly. The new converter is clean of metal dust and fragments. Every converter comes out of the box clean. This is almost an exclusive feature of MagnaFlow.

Resealable Boxes - MagnaFlow's converter boxes are made of a heavy gauge corrugated board that is three layers thick at the ends to protect the converters during shipment. The boxes are easily opened and re-closed, keeping the customer's inventory looking better, longer. Known throughout the industry as "the pizza box," it is yet another example of how we set ourselves apart from competitors.


Until recently Tail pipe testing for emissions has been the standard for most states with an Emissions Testing program. Over the last few years however many states have converted to OBD II testing for all light duty vehicles 1996 and newer.

Magnaflow - Emissions Testing

The testing consists of several steps to confirm that a vehicle is in compliance. They are:

• Diagnostic Connector Verification and Scan Tool Communication
• KOEO - Verify MIL Bulb Check
• KOER - Verify MIL NOT Illuminated
• Verify NO Codes in System
• Verify Readiness Indicators (Monitors) are complete

Magnaflow - Check Engine




Magnaflow - Emissions Testing
• P0420 - Bank 1 catalyst efficiencey below threshold
• P0300 - Random Misfire
• P0401 - EGR Insufficient Flow
• P0171 - Fuel Trim, Bank 1, System too Lean
• P0174 - Fuel Trim, Bank 2, System too Lean
• P0135 - O2 Sensor Heater Circuit, Bank 1 Sensor 1,Malfunction
• P0325 - Knock Sensor 1, Circuit Malfunction
• P0440 - Evaporative Emission Control System Malfunction
• P0442 - Evaporative Emission Control System, Small Leak Detected
• P0455 - Evaporative Emission Control System Large Leak Detected

Many of these codes are related to Fuel Trim and can directly affect the efficiency of the converter or the computers ability to monitor it correctly.
The following pages contain details of the P0420 code and specific testing techniques to aid you in diagnosing the vehicle properly… the first time.

Magnaflow - Diagnosing the Vehicle


Magnaflow - Converter Efficiency

There were many changes that took place with the implementation of OBD II but the change having the greatest affect on diagnostics was the Readiness Monitors. During operation, the on-board computer (PCM), continually tests itself and all emission components reporting to it. This monitoring process assures each component or system is operating within a pre-programmed set of parameters. The Catalyst Monitor utilizes pre and post converter oxygen sensors to continually check the oxygen storage capacity of the converter. During normal operation, the pre-cat O2 or Sensor 1 should display a rapidly changing voltage signal ranging from approximately 0V to 1V. The post-cat O2 will be flat line displaying little or no variation in it's signal.


A P0420 (Catalyst System Bank 1 Efficiency Below Threshold) or a P0430 (Bank 2), are indicators that the converter may not be functioning properly, but are not the end of the diagnosis. There are a number of steps that must be taken to assure that the root cause of the failure is found and repaired.

Magnaflow - Diagnostics & Testing
• Test drive the vehicle and note any driveability issues that may indicate fuel or spark delivery problems such as hesitation, stumbling, spark knock, or misfire.
• Check the tail pipe upon start-up. Look for any signs of smoke that would indicate an engine failure such as Oil burning (blue), internal Coolant leak (white) or rich running condition (black).
• Listen carefully for any signs of vacuum or exhaust leaks.
• Complete visual inspection of ignition, fuel and intake components.
• Scan Tool test. Avoid clearing codes until 'Freeze Frame' information can be retrieved.

This is a snap shot of what was going on with the vehicle when the code was set such as Temperature, vehicle speed, load, throttle position etc. Using this information you can duplicate the conditions that set the code in the first place.

Magnaflow - Diagnostics & Testing
Magnaflow - Diagnostics & Testing

Along with current codes, also look for any history or pending codes. Any Fuel trim related issues will have a direct affect on the converters ability to function properly.

These include but are not limited to:
MISFIRE: P0300-P0314
O2 SENSOR CIRCUIT: P0130-P0147, P0150-P0167
P0030-P0038, P0040, P0043, P0044, P0050-P0064
FUEL SYSTEM: P0170-P0175
INJECTOR CIRCUIT: P0200, P0261-P0296

Magnaflow - Diagnostics & Testing

• Check the OBD II Readiness Indicators (Monitors) to ensure all have been run to completion. One or more that read incomplete may indicate that the codes were cleared recently and you may not have a complete picture of the status of the engine and all its components.

• Check Short and Long Term Fuel Trim data (STFT /LTFT). STFT is directly related to the switch rate of the O2 Sensor 1 and is an indicator of current fuel control. LTFT is an indicator of the PCM's Fuel trim History and is a good way to determine if the vehicle has a history of running lean or rich. Either one of which could cause premature failure of the converter. LTFT is given in percentage. A lean running engine displays a Positive % because the PCM will be adding fuel to compensate while a Negative % tells us the computer is trying to overcome a rich running engine.



Magnaflow - Temperature & Shell Inspection

Catalytic converter shell coloration is a good indicator of Converter efficiency and light-off. Converter efficiency depends on factors including exhaust gas composition and temperatures Converter internal reactions (Light-off) begin to occur at Exhaust Gas Temperatures between 400 and 800°C. High operating temperatures should be avoided to prevent degradation of the converter. Always note any conditions that may prevent a converter from reaching Light-off temperature.


Check manifold and exhaust pipes for leaks
Check for any physical damage to the converter housing.
Inspect O2 sensor wiring to ensure good contact at the
connectors and no damage or shorted wires.


Technical Service Bulletins or TSB's are published by the Manufacturer to address particular issues, repairs or updates to a vehicles systems or components. Advances in technology have created scenarios whereby a software update to the vehicles computer may be all that is needed to repair a driveability issue. Intermittent MIL (Check Engine light) illumination, premature or false codes are also instances that might only call for a software update. Reprogramming or Reflashing are terms commonly used to describe these operations. TSB's are very specific and will clearly spell out what vehicles, systems and components the bulletins are addressing and what actions are to be taken including any updated components and/or reprogramming necessary for a proper repair.


Magnaflow - Converter Failure

Here are some common component failures that can lead to converter damage:

• Intake leak
• Exhaust leak
• Fuel Injector leakage
• Defective front O2 sensor
• Defective Mass Air Flow Meter (MAF)
• Defective Coolant Temperature Sensor (ECT)
• Defective Manifold Absolute Pressure Sensor

Following are the more common contaminants
that will affect O2 and Converter performance:

• Oil - Bad rings or Valve seals
• Sulfur - found in some low quality gasolines
• Silicone - found in most Gasket sealants unless
marked "O2 sensor safe"
• Coolant - damaged head gaskets or Intake


• Choose the right converter through application look-up.
• Replacement converter should be in same position as OE.
• Install all Oxygen Sensors as close to OE position as possible
• Maintain all heat shields for proper converter Light-off
• Always check for leaks after repairs