i have owned my 03 996tt about 6 months and had a CEL come on today. 37k miles, 6speed, no maintenance records. what else should i be doing while i am working on it. CEL was a missfire on cylinders 3 & 6


plugs - Bosch F5DP0R
coils - 997 coils
fuel filter - stock
oil - stock filter w/ rotella t6
exhaust is in the mail
new coolant - G12

future mods will just be bolt ons with a tune, nothing major

anything else i should take care of while i underneath the car?

 

pin the coolant fittings, go ahead and replace and bleed the slave, only a matter of time before it fails. if theres no records i would drain and flush all the brake fluid as well

 

Also check condition of the coolant overflow tank and the front radiators (clean any debris around them). Other than that, buy a boost leak kit and try to check at least once a year but maybe twice.

 

i am not dropping the motor for an ignition problem, but the brakes i can do

 

you dont have to drop the motor to pin the fittings merely lower it as far as possible by loosening the motor mount bolts and the trans mount. support it and lower until the coolant hoses are starting to stretch. from there with a small amount of knuckle bleeding you can pin all 8 fittings. wont stop small leakage but will prevent a blowout

while you have it dropped that far you will find the fuel filter and the coolant tank are much easier to change. also tie wrap as many vacuum lines as you can get your hands on. swap the check valve on the plenum for a new one they are prone to leaking boost

 

I agree a thorough boost leak / pressure check should be done. Though you might as well replace all 3-4 of the major check valves known to commonly fail while in there, with the motor lowered.

It's probably also a good time to tie wrap all the vacuum / sense lines that you can reach while in there.

Vacuum leaks are the bane of this platform, and possibly part of the reason for your CEL.

 

i'd prolly also change oil in front diff, rear diff, oem - i did that, do to Age. Brake flush, check cabin filter, also take air filter out, When i bought my car
i found leafs in the corner when i took the air box apart.

You may take the front bumper off, and clean around radiators, it collects bunch of rocks and crap. (usually when you drive thru winter i highly recommend)

Do boost leak at least ones a year -

Maybe Accessory belt? depends on the condition (easy to replace)

 

If you do get into the top of the engine. Defiantly zip tie all your vac lines ( FPR, reservoir, Diverter valve circuit, ECT. ) like previously stated as age and time will cause these to pop off and cause you many CEL's.
I total agree that having to lower the motor for maintenance is crazy talk but it is just a matter of time, not miles, before one of the coolant lines blows out of the casting and leaves you stranded. I would at least plan for this process if you don't want to get into it now.
Boost leaks are the haunting of these cars when modding so +1 on getting a leak check done. This will also verify if any of your vac lines have popped off yet if you don't want to get into zip tying them.
Switch to a Denso or NGK equivalent plug when you do them as the Bosch plugs are junk.
And obviously keep up on the service intervals and what maintenance it calls for and you will have a good life with her!

 

Yes, do this^^^^

I did the coolant fitting pins over the weekend; I pushed a fitting a couple of days after my first track day the previous weekend and replaced the loose one into its place with an aircraft-grade epoxy, pinned the other 7 fittings, changed the water pump, zip-tied everything vacuum related, then pinned the fitting I replaced after giving the epoxy time to harden. I didn't loosen the trans mount, probably would've made my life easier. I could've easily done it all in one day if I hadn't had to wait for epoxy to harden.

 

with those OEM you mentioned plugs they no longer recommend a "5" heat range in the bosch/beru those plugs ( fr6ldu oem for 996 gt2 ) are better suited to longevity and smoother running. hotter plug = better. go with beru fr6ldu or the bosch equivalent for a couple bucks more. they're pre gapped but i always go .027.

http://www.pelicanparts.com/catalog/..._pg1.htm#item0

also vw/audi G12 is alo superceded now to G13 coolant. same sh*t. just make sure it's "pink". mix 50/50 G13 w DISTILLED WATER.

 

Check the brackets for the variocam solenoids, they are small and will rust and crack and cause problems.
Doesnt cost much either, im swapping both mine these days as they started to get rusty.

 

Rotella oil not very good oil. Partially mineral oil based. Designed for use in slow revving diesels.

In your area I'd probably run Mobil 1 5w-50 oil. (Not a typo of 15w-50!).

My 2003 Turbo has been generating P0300, P0303, and P0306 error codes off and on now for way over 12 months.

Happens at cold start after the car has sat a day or so unused.

It has never misfired at other times.

I attributed it to the coils. They are/were original and had around 140K miles.

Last oil/filter service at 140K miles I had them replaced along with the plugs. Plugs were about half way to their change by miles but I decided to just change them early.

(O2 sensors replaced at 132K miles.)

Misfires still appear. Talked this over with a tech and he thought the problem might be a sticky injector or two. Even though I run Chevron gasoline with Techron. This stuff works: After few tanks through my Boxster the Boxster engine was running better; but the Turbo engine didn't manifest any improvement. I just attributed it to the Turbo engine being a cleaner running engine. (The Boxster engine has almost 300K miles on it too.)

Still the tech suggested I try a fuel system cleaner and even gave me a bottle out of his toolbox. I tried this cleaner and it hasn't seemed to make any difference.

Some have offered up as an explanation possibly something to do with the fuel lines or the fuel system. A fuel line can develop a crack/split I guess and at startup can result in less than optimum fuel pressure. Or a return valve leaks and lets fuel pressure bleed away after the engine is shut off and upon start up this can have some cylinders with too little fuel.

I really don't like the fuel system/fuel lines as an explanation but I can't dismiss them entirely either.

I have not yet touched based with the tech again to see what he has to say about the fuel system cleaner apparently not helping.

Engine otherwise runs just fine. Makes 0.7 bar of boost under hard acceleration and in every way appears to be in good shape so whatever causes the misfires appears to not be a problem at other times.

So we share the misfire problem but I have no solution to offer you.

 

fully synthetic oil available in 5/50 from walmart
http://rotella.shell.com/products/t6...sEmw&gclsrc=ds

 

It's possible for a fuel system to lose pressure and cause a prolonged crank at start however this will NOT result in any particular cylinder having additional fuel nor is it caused by cracks in lines external to the tank. Fuel pressure on the high side runs at least 3.8bar and any cracks would spew fuel pretty good! Misfire is going to be injector, spark system, or timing related.

 

Any P/N's for the check valves? i had a brake pedal that kept going hard on boost so sure it was one leaking.