Skip to main content

Richard Simonds

Tech Q&A

 

Using Star TekInfo


Q I am interested in maintaining my 2013 GLK350 as I have my older Mercedes-Benz cars for years, but am stymied by the lack of workshop manuals available. The online Star TekInfo system has been suggested, but accessing the information requires having an ID & password.  How can I get into this site?

A MBUSA Customer Service (800.367.6372) can supply owners’ manuals, but Mercedes-Benz Cars no longer publishes printed workshop manuals. Because cars have become increasingly complicated and ever more dependent on electronic engine-control modules, fewer basic maintenance tasks are required on the modern car – beyond changing the basics of oil, water and windshield cleaning solution – and most repairs require special equipment for both diagnosis and execution of procedures. Some independent garages and repair shops subscribe to the Mercedes-Benz Star Diagnostic System; this is a resource that is absolutely necessary to be able to do complex repair of the electronics embedded in a contemporary vehicle. The MBCA maintains a subscription to Star TekInfo, which has the Workshop Information System (WIS) and Electronic Parts Catalog (EPC) for models beginning with model year 1976. Contact MBCA Technical Committee Chair George Murphy at [email protected], or 865.482.9175, with your question or request. Just send him your VIN by email with your question and he will compile the requested workshop procedure files or vehicle data sheet.

 

No fan of run-flats

 

Q   I recently paid a visit to the BMW U.S. website and, for comparison’s sake, went through the online procedure to build an X3 to see how BMW stacked up to Mercedes-Benz. It turns out that BMW now provides a choice of either run-flat or conventional tires when a customer specifies a new vehicle. This is a no-charge option and includes a compact spare stowed beneath the rear compartment. I have been asking Mercedes-Benz to offer this same option for the GLC. I've been driving Mercedes-Benz vehicles since 1980 and would hate to change now. I was all set to buy a GLC until I found out that all vehicles sold in the United States are equipped only with run- flats. Regular tires are provided in Canada. Any chance MBUSA will follow BMW's lead?

A MBUSA works with Daimler AG and the dealers to set what models they will sell in the United States and how they will be equipped (with some variability for special orders). When I bought my 2015 C400 Sport 4Matic and my 2017 GLC300 4Matic, both fully optioned, I inquired about getting regular tires instead of run-flat tires. My dealer sales representative (with whom I have worked for 28 years and who has been able to get most everything I have wanted on my new cars) told me that MBUSA has no plans to offer anything other than run-flat tires. The trunk/hatch area is configured for other purposes and does not have room for a space-saver spare or a full-size spare tire. Some members who have faced this dilemma have purchased a wheel and tire and put it in the luggage space when touring. If you do this, be sure that the wheel you buy will work with the lug bolts on your current wheels. If not, buy a set of lug bolts that work with your vehicle and the new wheel. Hope this offers you some insights into where we are and how to "work around" the situations we have.


Feeling fuelish Down Under


Q I have a 1969 280SL and although the vehicle drives beautifully, it is burning an excessive amount of gasoline. I live in Sydney, Australia, and a colleague of mine who solved a similar fuel consumption problem a few years ago gave me your contact information. He said that you had written an excellent article on this subject. My regular mechanic advises me that this issue should be rectified to avoid doing damage to the engine in the long term. He believes the problem is rooted in the fuel-injection pump. My questions are: Is there a way of determining that the problem truly is the pump? If the pump is at fault, what are the options for fixing or replacing it? I have been advised that the resources in the United States are more comprehensive than what are available to us here in Australia.

A The article that I wrote a few years ago addressing this issue was keyed to solving the problem on 230SLs and early 250SLs. However, the basics should be similar. Here is the approach I suggest for determining what is going on.
Ignition System:
1. Check that the coil is putting out the recommended voltage, approximately 45K volts from the red coil (SLs) to the distributor cap. If the red-body coil has been replaced with a blue-body coil correct for the sedans, the voltage is approximately 18K volts. A weak coil requires more accelerator pressure, which will increase fuel consumption.
2. Be sure that the ignition timing is set correctly and that the dwell angle is set to factory specifications.
Fuel System:
1. Check for any fuel leaks in the entire fuel system, such as loose connectors in the fuel lines, rotted rubber connectors or loose clamps. If you do not find any fuel-system leaks with the engine running, go to Step 2.
2. Look for black smoke when pressing the accelerator – an indication of a fuel mixture that is too rich. If this is the case, the first thing to do is fine-tune all of the fuel linkages from the accelerator to the injection pump, right up to the intake manifold throttle Venturi. Until the linkages are precisely adjusted, no amount of calibrating the fuel-injection pump or intake-manifold settings will be of much use. Too often, mechanics or technicians who do not understand the system get it seriously out of adjustment.
3. Once the linkage is adjusted correctly, turn your attention to the mixture screw on the fuel-injection pump that is used to lean out or enrich the fuel mixture. Also, the throttle Venturi has an adjustment that can change idle speed by leaning or enriching the air-to-fuel ratio. Too lean a fuel mixture can lead to burned valves; too rich a mixture leads to fuel in the crankcase, causing failed bearings (crankshaft, connecting rods and even camshaft), as your mechanic stated. It is helpful if the shop has an exhaust-pipe sensor to measure oxygen levels to stay within the correct specifications.
4. A good workshop manual can provide specifications for oxygen levels and even have details on fuel-system adjustments.
5. The Pagoda Club (www.sl113.org) has a technical forum for members only that includes resources from its “Pagoda University” club gatherings, with specifics on adjusting the linkages and the fuel-injection pump and specifications on the correct air-fuel ratios. After logging into the site (you can join online and dues are reasonable) select the “Technical Manual” link, click on “Fuel System,” scroll to “Maintenance” and choose “Fuel Injection Linkage Adjustment and Idle Adjustment Procedure.” I hope this helps you resolve your fuel consumption issue.