What’s more important as far as I’m concerned is the ability to understand the systems and how they work. The bad thing about this later stuff is that a lot of that interaction is shrouded in the CANBUS chatter or the full extent of the interaction can’t be easily understood.
Since the crank position sensor is critical to engine starting, when the engine cranks but won’t start it’s almost absolute that it’s the problem. Despite the electronics, there still has to be analog inputs such as the waveform that comes from the CPS when the crankshaft ring gear teeth pass by it. I was pretty sure it was the culprit when the engine cranked but didn’t start. No fire, no fuel, nada. The sensor’s typical failure mode is for the output to drop at high temperatures. Since the car had just come off the highway and was hot, sitting in the parking lot for 5 minute or so while I ran into the store allowed the engine to hot soak and the temperature around the sensor to climb significantly. I sat for maybe 15-20 minutes and the temperature dropped enough for it to start working again. Once the engine begins running, other inputs can “cover” for the CPS if the signal is poor or intermittent, I suspect. So now it’s work from home tomorrow while I wait for Amazon to deliver the new Bosch replacement. Maybe 10-15 minutes to replace from the top side of the engine. Dan > On Feb 1, 2016, at 6:17 PM, Curt Raymond via Mercedes <[email protected]> > wrote: > > People are scared of the computers but I don't know why. The computer helps > you troubleshoot exactly the problem rather than just shotgunning parts. > Which reminds me, the '05 Golf turbo seems to spool up late, I was hoping an > Italian tune up would help but I've been driving the snot out of it and other > than the fuel economy seems to be rising I don't see much difference. I need > to put my laptop on it and watch the pressures and see whats going on. Its > cool that you can watch it real time and very nice with the VW that all you > need is the $250 cable and a Windows PC. Interestingly I'm running Windows in > Virtual Box on a Mac and it works just fine... > > -Curt > > > From: Dan Penoff via Mercedes <[email protected]> > To: Mercedes List <[email protected]> > Cc: Dan Penoff <[email protected]> > Sent: Monday, February 1, 2016 6:06 PM > Subject: [MBZ] Diagnostics > > A good example of how you don’t always need a fancy DAS system to work on > later cars: > > S430 cranks but won’t start after a stop on the way home from work. Sat and > let it cool off for maybe 15-20 minutes. Cranks right up. > > Crankshaft position sensor, I’m betting. Classic symptoms. > > Drive the car home, put it on the DAS. Fault code for the engine ECU - > “Crankshaft position sensor”. > > Amazon has Bosch available for under $40 to my doorstep tomorrow. > > Nice. > > Dan > _______________________________________ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > > > > _______________________________________ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
