We’ve moved Jason’s Space blog to the Autobahn Performance website at http://autobahnperformance.org. All new posts will appear there, not at jayauto.wordpress.com.
Hosting Jason’s Space at WordPress.com has been fine, but by hosting it at our own website, we add flexibility that’s impossible on WordPress.com.
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Jason Athanas
Jason recently observed a factory Mercedes webinar for the complex problem of diagnosing and repairing Mercedes SCR systems for diesel cars and trucks and Sprinter vans. We put this knowledge to use today for repairing a 2010 sprinter van with an SCR problem. SCR stands for Selective Catalytic Reduction and the vehicles that have it are usually labeled or badged ” BlueTec ” It is the environmentally-friendly diesel technology from Mercedes-Benz used to reduce emission levels. BlueTec uses Urea or diesel emissions fluid injection into exhaust gas stream in specially designed chambers in the exhaust to reduce emissions, especially NOx (oxides of Nitrogen). The factory scan tool can be misleading and it is common for technicians to misdiagnosed the system and change expensive parts needlessly. This fairly new technology uses the Mercedes SDconnect to connect directly to the high-speed chassis CAN network of the vehicle. This allows monitoring of the raw sensor data and non calculated information for precise diagnosis. The factory Xentry scanner cannot display and process this information the way this specially designed package can. On this vehicle we discoverd a slight difference in the NOx sensor readings between the front and rear sensor and this led to diagnosing a faulty front NOx sensor. These sensors are around $600 at the time of this article but this is still way cheaper than if it was misdiagnosed as an SCR failure (currently $3700).
Autobahn performance is doing another air mass meter wire harness repair. We are getting lots of these cars in for the repair, even being shipped in from across the country. We can repair the air mass meter portion of the Body mounted engine harness without removing the harness. Do not attempt to cut open the body harness and repair the wires, this customer did and ended up cutting and damaging non deteriorating wires. You can see in the pictures the wires are molded into a pass-through loom it is impossible to separate and untangle the wires without damaging the entire harness. We have repair harnesses in stock to repair the body-mounted engine harness on v12 600’s. Usually, only the air mass sensor wires fail. $295 each 2 needed. The harness can be run alongside the factory harness sheathed in long lengths of heat shrink tubing and connected directly to the engine computers. The other harness’s common to fail are the lower engine harness (also called starter harness or positive cable harness) we can repair your damaged harness but it may be available at a reasonable price from the dealer (get me you VIN and I will get you a price) The throttle actuators have harness’s that come off of them and connect to the body harness. These harness’s fail internally, to check them you need to carefully make a 1-2″ incision in the covering of each actuator harness and examine the wires inside. If they are bad we can rebuild your actuators (done in house) $695 each includes internal motor, plastic gears and new cable harness connector end is disassembled and re-used. The fuel injection harness sits on the top of the motor and is usually available from the dealer at a reasonable price. These can be rebuilt by us but must be inspected to give an accurate price. The body harness of the car usually does not fail or deteriorate on 129 SL’s if it is it probably should be replaced with new from dealer we could rebuild this harness but it would be expensive and time consuming.
This car came in with the computer box disassembled and the computers removed. call us before you attempt to do this yourself. Autobahn Performance 954-771-5181
New and old air mass meter connectors
Our good friend Rolf Engelfried had his very clean and original 1981 Volkswagen Rabbit Diesel towed in to the shop with a non working clutch. We had adjusted the clutch cable on a previous visit and thought the clutch may have failed. After inspection it was discovered that the clutch cable had broken its retaining bracket off of the steering column and the cable casing was pushing against the firewall instead of the bracket under the dash. I remember working on a lot of these cars at my uncle’s repair shop J&R foreign cars of Lowell Massachusetts in the late 80’s and remember seeing this before. Unfotunately the only way to fix this properly is to completely remove the steering column form the vehicle and re-weld the bracket in place. We ground the old weld mostly off and cleaned the area on the column where the new welds needed to go. We welded the bracket on more than just the two ends that were welded from the VW factory. Here are some pictures.
Autobahn Performance has recently purchased the Verus Pro d10 the top and latest diagnostic platform from Snap-On tool Inc.
At Autobahn Performance we can sometimes save money and time for customer by repairing cracked or cold solder joints. Manufactures seem to use too little solder at times and joints with high current / heat tend to crack over time. We are experienced at repairing these circuits. Here are some images of a recent circuit repair.
It’s been a while since I needed to use this trick and it saved me (and the customer) about 8 hours of labor. This 2010 Mercedes C300 204 chassis vehicle broke the rear axle shaft (1/2 shaft). It sheared clean off where it comes out of the side of the differential. Vehicle was in a minor accident and somehow the axle twisted and broke. We used a miller stick welder and the largest diameter welding rod we had around. We let the rod get a good molten puddle going in the center of the broken axle stub and then pushed the electrode straight into the weld puddle stopping the arc. We quickly unclamped the rod and shut the welder off. After allowing the rod to cool we used a slide hammer with a vice-grip attached to the pulling end (This is also a neat and usefull trick / tool I made). I tightly clamped the vice grip to the end of the welding rod and with one good pull of the slide hammer the broken stub popped out still attached to the electrode. The new axle went in fine and everything worked good without removing and disassembling the differential.
