Archive for the ‘Cars’ Category

Fault Logic

Friday, June 1st, 2012

A few weeks ago I had a recurring problem with my 2010 Jetta TDI which caused the check engine light to turn on. Fearing the worst I contacted VW only to learn that this merely indicates an emissions issue. Apparently, its only when the engine light blinks that the driver should panic stop the vehicle for fear of imminent doom.[1]
Once I dutifully delivered the vehicle to the dealer they hooked up the magic diagnostic computer. As far as I can tell this mystical device is essentially a USB dongle and a laptop computer. This modern oracle revealed that one of the injectors had failed to deliver its due share of fuel to the engine. Diagnosis: “You probably got some bad fuel.”
So the next day, yes, that’s right, the light is on again. Another trip to the dealer and the same diagnosis. Solution: Finish the tank of fuel and run another one through it. If the injector is bad it will continue to be bad, if it’s fuel it will probably go away. Next day, light comes on again, but I ignore it. Fast forward to last week and about half way through the new tank of fuel… light goes out. [2]
After speaking with the service manager, we agreed to monitor, but that it probably really was just bad fuel.
Through this whole adventure, I found myself wondering why the multifunction display in the middle of the dashboard can’t provide this information directly? Why can’t I push a button and have the car show the code information right on the screen? “No”, you say, “if they did that, then we wouldn’t be able to pay the dealer $75 to do it for us.”[3]
So today, I’m on my way home, and what do I discover the German engineers have decided is worth my immediate attention:

There’s no need to inform the user about the inner workings of the engine, that ancillary system that MAKES THE CAR GO. The license plate lights: yes, a special light-shaped indicator and diagnostic text.

  1. At the time, I was about 10 miles from where I was going and decided to keep driving anyway, since the engine showed no signs of having any difficulty. []
  2. It resets after three ‘warm up’ cycles without an error. []
  3. I paid nothing because I’m still under warranty. []

500 miles on 13.4 gallons

Tuesday, November 16th, 2010

For those keeping track at home, that works out to 37.3 mpg. The observant reader will note that the average consumption shown on the MFD is 38.9 mpg. The discrepancy is due, in part, by the fact that the main trip (bottom right 500.0) and the trip used for the calculation are not, in general, synchronized. (More on that below the fold.)
The other observation (which you can’t see, but I did) was that the estimated range remaining was down to about 25 miles or so. This despite the fact that the fuel tank is over 14 gallons (plus the filler tube). So if I only put 13.4 in, there must have been over a gallon left, or over 40 miles of range remaining.[1]
(more…)

  1. This poor range estimate may have been due in part to the silly circles I did just before stopping at the pump to make sure I made it to 500 miles. Not very efficient I know, but I wanted the picture to look that much sweeter. []

First Tank…

Tuesday, November 16th, 2010

Well, I have almost exhausted by first tank of fuel in the Jetta. This morning the fuel pump indicator lit up on the dash and the MFD showed that my remaining range had dropped below 45 miles.
Of course, this was on the way to work (which is net downhill by about 1000 feet), so after driving almost 20 miles it still said I have 40 miles of range left. I’m over 475 miles for this tank, so I may see how much I have left at 500 miles. :)

Jetta TDI vs. Acura Integra

Friday, November 5th, 2010

So I mentioned my shifting issues in my previous car related posting. Although I’m doing much better, I’m still working on getting the feel[1] for the new drive train.

Generally speaking, the TDI provides more torque at low RPM with proportionally less power at high RPMs. The red line is at 5000, and for the ‘break-in’ period I’m trying to keep it under 3000. The 1997 Integra LS by comparison, engages the rev-limiter at 6800 RPM and one can easily get up into the 5-6000 range in road driving.

Much more car stuff, including musical engine comparisons, below the fold…
(more…)

  1. Literally, because I think one feels shifting from their backside and ears rather than by watching the tachometer. []

Jetta TDI: First Thought

Tuesday, November 2nd, 2010

K upon sitting in the drivers seat and taking in the array of controls and displays: “It’s a bit… overwhelming, isn’t it.”

That sort-of sums up my initial reactions as well. Not being the sort-of person who’s willing to leave a button unpushed or a menu unexplored one can quickly find yourself in information overload. This is not recommended while driving your brand new car home at night.

Combine that with the fact that the combination of the turbocharged diesel engine and the 6-speed transmission give the vehicle an entirely different feel than my 5-speed high-RPM Integra. For instance, red-line on the Integra is roughly 6800 RPM vs. the TDI’s 4500 or so. Reverse is now on the left of the shift lever (and requires a ‘push-down’ to enter the detent). So twice now I’ve shifted into 6th (far right and down) when I meant to go to reverse. Thankfully, this is a relatively safe failure mode since even with the low RPM torque, you won’t jump right off in 6th gear. I’ve stalled the car something like 6 times since I picked it up last night. I haven’t figured out where the right clutch transfer is for this engine yet. All of these issues are growing pains, and will, no doubt, quickly pass (until I drive K’s Accord and everything goes back the way it was).[1] Once I’m going, the shift points are all different. The TDI operates at whopping 236 ft-lb maximum torque from about 1750 to 2500 RPM. This means the engine sound is much lower pitched than I’m used to for shifting.[2] The acceleration is such that you blow through the available RPMs rather quickly so you require shifts at lower speeds. I’ll look up the gear ratios in a future post and do a comparison.

For now, I’ll be satisfied with not stalling or hitting the rev. limiter.

Oh… my drive to work clocked in at an average of 47 MPG.

  1. I’m hoping the lack of the reverse push-in wil prevent me from putting it in 1st when I intend to back up… that would not be a safe failure mode. []
  2. I typically shifted my Integra in the 3500-4000 range. []

Losing ability to concentrate…

Monday, November 1st, 2010

See two posts down.

[twitch]

[twitch]

Must

hold

on

until

5PM.

A New Car!

Saturday, October 30th, 2010

Bu-dump-da-daa-Dah-dah-dah-dum-dada-dah-dah-da-dah…[1]

Yes, I finally pulled the trigger on a new car. I’ve had 13 good years with my Integra, but it’s finally time to let it go. We pick up the new car Monday.

So what did I get? A 2010 VW Jetta TDI. That’s a 2.0L turbo diesel for those not familiar with the VW branding. The diesel wasn’t a primary selling point, since in my calculations it’s about a wash relative to the unleaded models. Better mileage, but higher fuel and oil costs.[2] I don’t drive enough miles in a year to see a huge cost savings, but the range is pretty amazing with something like 600 miles on a tank. Lots of nice interior features in a metallic grey exterior and a black/grey interior. 6-speed manual, Bluetooth interface, iPod data connector, 115 VAC accessory connector, moonroof, etc.

Here are some mug shots courtesy of K’s iPhone:
2010 VW Jetta TDI Right Front

2010 VW Jetta TDI Left Front

2010 VW Jetta TDI Interior

  1. Think Price is Right []
  2. VW specifies a fairly exclusive synthetic motor oil for the TDI engine, but then they claim you only need to change it every 10k miles. []