Tuesday, June 29, 2010

Engine Speed Sensor R&R

Or it is also known as the crankshaft position sensor.  As stated in my last post, I needed to replace the engine speed sensor on the Touareg because it was not starting every time.  Anyway, here is a little write up on how to replace this sensor.

First of all, here is a bit from my manual which does not shed enough light on how to get this done. 

Volkswagen Touareg 
ENGINE PERFORMANCE 4.2 Liter V8 5V Generic Scan Tool, Engine Code(s): AXQ, BHX 

Engine speed (RPM) sensor, checking 
The Engine Speed (RPM) Sensor -G28- detects engine speed and reference marks. Without an engine speed 
signal, the engine will not start. If the engine speed signal fails while the engine is running, the engine will stop 
Recommended special tools and equipment  
VAG1526 multimeter or VAG1715 multimeter  
VAG1594 connector test kit  
Wiring diagram  
Test requirements  
Ground (GND) connections between engine and chassis must be OK.  
Ignition switched off.  
Test sequence  

Disconnect gray 3-pin harness connector (arrow) to Engine Speed (RPM) Sensor -G28-.  
Measure sensor resistance between terminals 2+3 at connector to sensor.  
Specified value: 480 to 1000 ohms 
Check sensor for short circuit between terminals 1+2 as well as 1+3.  
Specified value: infinity ohms 
If specified values are obtained: 
Check wires according to wiring diagram. Refer to Checking wiring.  
If specified values are not obtained: 
Replace Engine Speed (RPM) Sensor -G28-.  
Erase DTC memory of Engine Control Module (ECM). Refer to Diagnostic mode 4: Reset/erase 
diagnostic data.  
Generate readiness code. Refer to Generating readiness code.  
Checking wiring 
Connect test box to control module wiring harness. Refer to Connecting test box for wiring test
Check wires between test box and 3-pin connector for open circuit according to wiring diagram.  
Terminal 1 + socket 108 
Terminal 2 + socket 90 
Terminal 3 + socket 82 
Wire resistance: max. 1.5 ohms 
Also check wires for short circuit to each other.  
Specified value: infinity ohms 
If no malfunctions are found in wires: 
Remove sensor and check sensor wheel for secure fit, damage, and run-out.  
If nothing seems to be wrong with the sensor wheel: 
Replace Motronic Engine Control Module (ECM) -J220-. Refer to Engine Control Module (ECM), 
NOTE: There is a larger-sized gap on the sensor wheel. This gap is the reference mark 
and does not mean that the sensor wheel is damaged. 

After reading that and looking at a couple of pictures, it was still not clear what it took to remove and replace this sensor.  I definitely knew how to test the sensor.  Here is the engine bay before I started.

Then I removed the plastic covers.

I had to buy spring clamp pliers to remove the spring clamps of the intake hose.

I then removed the intake hose.

Not very much room to work with behind the engine.  This is where the upper connection of the sensor is located.  As you can see in the second picture.

You can see the gray connector in the mirror.  Not an easy location to get your hands.   

I also removed the bottom plastic cover.

I also removed part of the hood support so that I had better access.

This process in total took me about 1.5 hours to complete.  Not too bad.  The part cost about $115 and the dealer would get about 2 hours of labor or about $200.  

Monday, June 7, 2010

Touareg Woes

The Touareg has been having its moments lately.  It has a bit over 80K miles and several items are needing replacing such as timing belt, water pump, thermostat and all the pulleys and tensioners that go with it.  However, while waiting for my appointment to replace my keyless entry unit by the dealer that was malfunctioning, the Touareg decided to overheat.  On the side of the road, I did all of the usual things such as check for leaks, check for water in the oil but nothing could be found.  So I called a tow truck to get it home.  After getting towed home, I checked the coolant level and found it to be a bit low.  I added water and it took only about two cups of water so not really low.  I then did some research and concluded that the thermostat was the culprit.  I called the dealer for a price and since the thermostat is behind the timing belt, and decided to get it all done while I was at it.

$1400 later, I was on my way home from the dealer and the Touareg overheated again.  I called the dealer back and they came and got the Egg and gave my another loaner.  The next couple of days and I got the Egg back working in regards to the overheating.  I forgot to check the keyless entry while at the dealer.  I checked when I got home it was not working.  So I called the dealer back.  I still need to bring it in to have them look at the keyless entry again.

Now, I have yet a new problem that just came about.  Now, the Egg is cranking over but not starting.  It has done this to me on three different occasions.  After about a dozen tries and waiting several minutes, it finally starts.  I did some investigation and have determined that the engine speed (RPM) sensor is going bad.  I worried that one of these times it will not start at all.  I will be testing the sensor this week if I can physically locate it.  If bad, I will replace it.  It appears to cost about $70 to $100 to buy online. More on this later.

In search of oil leaks

I have started the investigation of oil leaks of my bus engine.  At the same time, I have sent my dells to Air Cooled Engineering (ACE) for rebuilding.  They have had my carbs for a little over a week now.

ACE called and informed me that they are working on my carbs.  They will be bead blasting inside and out.  I had installed the Jet Doctor from CB but the people at ACE do not like the Jet Doctors due to tuning issues when using them.  So we are going to go back to stock jet holders.  Also, I had installed small vents (30mm) and found out that the air jets were 200s and not 180s as marked.  So, we are going to go back to the stock vents (34mm) and get 180 airs installed and test.  I have to send these (other  than the 180 airs) parts to ACE so they can install and test.

Right now, the motor is on the floor in the garage and I have removed the crank pulley to look behind it.  I do find some oil that seemingly is coming from the pulley hole.  This is probably due to blow by from the rings.  Next I will be removing more components from the engine.