At 31,000 miles I had a high boost misfire in cylinder #2. Bentley tech said it would be the plugs not the coils. To replace the plugs I followed the instructions in the existing DIY spark plug thread with some differences.


As previously mentioned I broke the small plastic tube off the sensor I was removing from the front of the engine in step #7. Attached photos show how I repaired the sensor with a piece of brass tubing JB Welded on to it. Works fine and is stronger than the original plastic tube. I had to cut the clamp off the tapered hose to get the small piece of plastic tube out that broke off. I used a spring clamp as a replacement. Its a very small hose and clamp.

If I had to remove that sensor again I'd file or grind off the two "****" near the outer edge of the bracket that make it difficult for that sensor to slide off. (see photo of bracket)


Since I was having difficulty unplugging wire connectors I chose to leave the wires connected to both MAFs. I just flipped the air cleaner boxes over and set them on the cowl. (see photo)


I tried the trick of not disconnecting the hoses at the rear of the intake manifold and just propping it up with a spray can. That didn't give me the free access to the coils and plugs I wanted. So I went ahead and cut the two hose clamps and removed the intake completely. Upon reassembly I used to high pressure fuel injection clamps to replace the two original clamps. (see photo) I have two of the OEM clamps but not the tool to squeeze them.


The plug in cylinder #2 was rather black compared to the others. To be cautious I replaced the coil for that cylinder as well as the plug. Got the coil for $30 from my local VW dealer. (see photo of new and old coil and part number on box)


The DIY instructions say the fuel rail and intake manifold bolts are torx. I found out the hard way mine are internal hex head. I took them out with a torx and while putting them back in with a torx I stripped out the head on one manifold bolt. That's when I noticed they were actually internal hex, needing an allen wrench not a torx drive. Those bolts are not in the VW system anywhere in the US. I looked for a substitute and with no luck. Best bolt I could find was 1/2" too short. So I repaired the head and installed it using an allen wrench.


While everything was apart I cleaned the MAFs, two air sensors in the intake and throttle bodies with the appropriate spray cleaners and installed new air filters. Interestingly the instructions on the throttle body spray can said not to clean throttle bodies for supercharged or turbo engines. (Wonder why?) As a result I went very minimal with the spray.


Car runs great now.


My biggest problem was separating electrical connectors. You have to loosen and lift the manifold to get some of them off. Don't forget to reconnect those before reinstalling the manifold bolts.


BTW, in addition to changing the plugs I'm doing the 40,000 mile/4 year/8 year service. I bought a kit of all the parts needed for this major service on ebay for $450 USD. Has spark plugs, clamps, manifold gasket, lots of filters, oil pan plug and gasket, new wipers, etc. Seemed like a good price. Dealer wanted about $750 USD.

 

Congrats, glad she is running great now. Yes, eBay has some nice deals for DIYers on service kits.

 

....it was very good and helpful of you to share your experience...I am having quite a time just changing the main battery...JimB

 

Great write up. Did you have to disconnect the batteries when changing the plugs?

 

No need to do that. No connection between the batteries and spark plugs.

Never disconnect the batteries unless necessary as all sorts of reprograming will be required.

 

....thanks for sharing your spark plug experience....let me share mine....my Bentley dealer ripped me off (never again)...without my ok...replaced my plugs...this was with 15,000 miles on car, cost around $600...fortunatly, I always ask for my old parts, the plugs removed were like new...I have them here on my desk...to remind me of thieves that smile and stick it to you...
.....On your job...the original hose clamps are better and cheaper than the screw type...the originals are Oetiker and can be crimped with conventional Tile Nipper tool...they are better because can't loosen with vibration...JimB

 

I followed the DYI spark plug instructions and it took me about five hours. I took my time making sure i didn't mess anything up. Next time i can do it in three hours. I found a work around for step 7 to remove the sensor up front. I tried a panel popper but could not get it off the bracket. I purchased a set of star allen wrenches and took out the small screw and it worked like a charm. Easy to change plugs yourself.

 

....hello 9GT...that was great idea with the star allans...anything that makes it go easier...when they designed these things the last thing in mind was making service doable...what do you think about apparent difference in manifold bolts....one says torx and other internal hex...do you think both types were used....JimB

 

My bolts were internal hex. Following the DYI advice was a heads up to check them.

 

I've been working on cars for 45 year and have never heard of a screw clamp loosening.

Note that the clamps I used were not worm clamps but OEM clamps used on many cars for high pressure fuel lines. If they were a problem we would have read about the numerous engine compartment fires and recalls by now. Also the advantage to these clamps is they can be removed easily and reused. Not so with the OEM Bentley clamps. I actually got two of those in my 40,000 mile service parts kit but chose not to use them.

Be careful using tile nippers to close the clamps as they can overstress the clamps and lead to failure. In other words if you overdo it you can nip right through or partially through the metal. I believe the correct tool is designed to stop before you get to that point. Could be wrong about that though as I don't have one.

 

....Hello Vette...I was not criticizing your use of screw clamp (actually perhaps I was)...Just to one up you...I have worked on my cars since before you were born and none of my screw clamps have worked loose either. Manufacturers use the Oetiker clamp because they are cheaper, easier and quicker to install and permanent with no possibility of over tightening if correct size is used and no possibility of loosening caused by inadvertent installation...
....tell you short story on subject...back in mid 70's had a Ferrari Daytona with 6 Webbers, while trying to do the impossible (getting all 6 in sync) I replaced the original gas lines with some transparent hose I had...For another reason I had car over to Bruno's garage in LA...Bruno was a former Team Ferrari Racing mechanic who knew Mr. Ferrari personally...(another time I'll share the story of our racing Daytona winning 1st overall at 24 hours of Daytona with Rick Mears and John Morton driving)....anyhow without telling me, Bruno stripped off all my fancy transparent gas hose and put original black hose on...just old school thinking...JimB

 

Like you Ferrari mechanic I'm all for originality too. That's what the Corvette restoration world I'm heavily involved with is all about. But in this case I chose to go with non original clamps. But I still have two of the correct clamps if I ever want to go back to the original parts.

 

....do you still have the 1954 Corvette...the reason I ask is because I remember it like yesterday...when it first came out...it was all of $4800...I believe it had the GM truck motor in it...The Chevy dealership in Jersey City drove on down to my work for a test drive...the first American "Sports Car" with Ford's ThunderBird to follow, the two seater...Of course the $4.800 was far above my budget...settled for a new Red Ford Sunliner Convertible for $3,000
Just back from Korea...them were the days...JimB

 

This is the 4th one I've had. Still working on it. 80% restored.

I believe I have read several places that it sold new for $3200-$3500. Still very spendy back in the day as I believe the typical Chevy sold for about $1800-$1900.

 

....you may be right as to the factory suggested price but they were rare commodity and unless I'm mistaken this only Chevy dealer in Jersey City put price od $4800 on it. Right at this time they were advertising a new Chevy basic model for $1750...I forget if the one I test drove was stick or automatic...we also had a dealership up on the "Hill" (fancy part of Town) that was showing the new "Tucker" a prototype...just taking orders and deposits...you got special leather luggage that fit into triangle shape trunk...When a truck ran into me head on on and icy road upstate New York and totaled my new Sunliner, my Collie dog went through the windshield, I dove under dashboard...no seat belts then...That is when I got the best looking Buick, the 1954 Skylark, it was one year old, the dealer had bought it for his son, who I bought it from...would you believe I took out the Dynaflow and put in a Packard floor stick and 4/11 rear end...I was running with drag strip crowd then...used to close off Rt 9 or whatever Hyway in Union N.J. an run em...crazy days