DRX: Batu Cave Bad-Hat (Case 2006)

DRX : Batu Cave Bad-Hat Installer & Mercedes Benz W126 (Case 2006)

In 2006, I have encountered many bad-hats installers who operate their installation companies solely on profit-greed and minus vehicle safety. During this timeframe, there are only 14 licensed NGV workshop around malaysia and 60+ NGV stations. Some bad-hat installers were converting vehicle beyond their technical knowledge. Many choose to 'MacGuyver' method on their customers' vehicles. Here is one case worth mentioning out of many cases seen and assisted back then.

Around June 2006, I have received a telephone called from a Mercedes Benz W126 owner, Mr Steven Wong, whom explained that his vehicle is experiencing massive power-loss. Here was he problem then:

Vehicle: Mercedes Benz 280SEL

Engine: W126 (6 cylinder inline, or popularly known as black engine)

Fuel System: Bosch K-Jetronics (Semi-Injection or Fuel Divider)

Size: 2,800 cc

Age: 20+ years

Ownership: 3rd owner under his name

His Complains were: His 280SEL has unstable engine performance in the morning, where he needs to operate his car at least 10 minutes on petrol mode. After that, he need to switch back to petrol on hill-climbs, during traffic jams and carrying more than 3 persons on board. In addition, his 280SEL would stall when he reverses his vehicle or conduct a full-steering turn. His top speed on flat road (or highway) at 60kmph and MRR2 highway uphill ramps at 10kmph. Often, his idling is very unstable and difficult to drive. He has endured this problem for 3-4 months, and has visited his installer for 10-20 times in 3 months. The common answer 'Your W126 engine has problems, not NGV system' given by his Batu Cave Installer.

Here is what we have found during our routine diagnostic of his problem.

Picture 1: A Pipe in replacement of a K-Jetronic NGV Mixer
Bad-Hat Installer called it as 'Universal Pipe'. Elegant as it sounded

This particular 280SEL is installed with a Landi Renzo TN-1SIC reducer (oversize) which needs a proper NGV mixer to function properly. However so, his bad-hat installer installed a rubber pipe, and named it elegantly as 'Universal Pipe' or less gracious, 'Multipurpose Pipe'. Plainly, a mixer device create vacuum by itself (based on Venturi effect), and pulling in the correct amount of gas to the K-Jetronic airflow. In layman's term, the mixer is needed to determine the right amount of gas on the Landi Renzo reducer that should be supplied to the K-Jetronic (or gas-on-demand). No rubber pipe would function with Venturi Effect. It is just a pipe!

The solution is to remove the 'Universal Pipe' and have it replaced with an imported K-Jetronic NGV Mixer. It was specially flown in for the 280SEL in August 2006.

Picture 2: Power Valve & K-Jetronic Mixer (right)

The cost of importing this special mixer was at Euro100.00, inclusive of the power valve. The order took about 2 months to arrive.

Picture 3: The NGV Mixer sits on the mouth of the K-Jetronic

The NGV Mixer is designed to sit on the K-Jetronic mouth. The airfilter casing will be installed around it and fitting nicely in between the airfilter and the K-Jetronics.

Picture 4: NGV Mixer is sealed with quick-dry casket silicon

No air should be allowed to leak into the NGV Mixer at the gap between the NGV Mixer bottom and the K-Jetronic mouth piece. If there is a leak, the venturi effect would be reduced and the engine response will be delayed.

Picture 5: NGV Mixer and Airfliter casing

Due to original hole made for the 'Universal Pipe', we were limited to reuse the hole for our mixer connection. It took me about 5 years to get the hole resize and corrected for our mixer unit attachment. We were not able to introduce a new hole as it is dictated that we reused the original hole, although it is highly inefficient. Thus, it is very costly and time-consuming if a NGV vehicle is installed improperly.

Picture 6: Mercedes Benz W126 completed with K-Jetronic Mixer

Immediately, the engine idling was stable and the power output was good. Later we added a Timing Advance Processor to advance the 280SEL ignition timing. This lead to more power improves, drivability and stable idling. The vehicle still feel heavy as it is a heavy and old vehicle. It no longer suffer problems like low speed, poor uphill climb and engine stalling.

The total bill was RM900.00 on equipment, excluding labour cost. It took me and another installer, Thierry Le Marrec, about 6 hours to complete the entire repair process. And it was really hard as the original installer ignored all safe installaton methods.

We hope that potential NGV users consider properly on their choice of NGV installers. Please do NOT expect cheap conversion price is the best; in fact, it is the worst package. It is likely that you are getting a Universal Pipe than a K-Jetronic Mixer! It is not the first case, and it has NOT been the last too. There are about 50+ Mercedes Benz W124/126 are still experiencing problem with their cars.

Be Safe, Drive Safe. DRX

email: drxander@ngv.com.my