TUNEUP INFO
Please note that Bill's Porsche 944 World is not responsible for the content of banners displayed above.
Bill
Underwood's Porsche 944 World. This page details basic 944 Porsche
tuneup information.
|
TUNEUP INFO |
|
Please note that Bill's Porsche 944 World is not responsible for the content of banners displayed above. |
|
http://www.oocities.org/MotorCity/1760/tuneup.html 
944 Tuneup Overview What's involved in a 944 tuneup? Not much, really. Change the plugs, cap, and rotor. That's a basic tuneup. Don't overtighten those plugs, and use good quality Bosch or Nippon parts, silver at the least, platinum if you don't mind the extra cost. For some reason, I've never wanted to use American plugs except for the SplitFires I currently run. If the cap and rotor appear good -- meaning no cracks or excessivly burned or pitted electrodes -- then clean them throughly to remove carbon tracks and grime. Simple isoprophyl alcohol and a rag are fine here, just make sure the parts are bone dry when you put them back on, or you'll flash-ignite the vapors inside the cap when you start the car. The 944 maintenance and tuneup video shows the technician using a very healthy blast of brake cleaner to clean out the cap, and in my opinion this rather severe for this purpose. Plus, I hate being around too much brake cleaner, because it is really nasty stuff... Now give the terminals in the cap a GENTLE once-over with some very fine steel wool; I've used the "four-nought" or 0000 grade stuff. Same for the rotor. Make sure you did not lose the rotor's set screw! Wipe everything down once again to remove all particles, and blow them off with compressed air if you have it available. Reinstall the cleaned, dry parts. For a more advanced tuneup, you might also replace the fuel and air filters.
Can I adjust my car's timing and fuel mixture? As in, during a tune-up? No. Timing and mixture are set by the DME computer brain. Timing is set by the crank position as read by the hall-effect speed sensors on the flywheel. Mixture is set by varying the amount of time the injectors are open. You can, however, make small adjustments to these computer-set values right on the DME box. Not sure where the DME is on your car? Check my DME page for info on locating it. Certain Motronic DME's have a tiny rotary switch on them. The idea is to allow qualified service technicians (or you, the knowledgeable tinkerer) to adjust fuel mixture and ignition timing to supposedly "compensate for the quality of locally available fuel." Of course, fooling around with this might help your car's performance, it can also hinder it. You might have problems come emissions-test time, so keep track of what you're doing here. The eight-position rotary switch is found through a little hole at the back of the DME box. The switch has a triangular-shaped recess in which to insert a special adjustment tool. In the 944 FAQ it says you can whittle down a golf tee to make one. Apparently, all DME boxes are set on position 1, so that's usually considered the factory stock position. The switch will click in detent positions, so you must count the clicks in order to shift the DME's timing and mixture settings to your choosing.
Can I adjust my car's idle? Again, not really. Idle is set by whether or not the auxiliary air valve is open or closed (it depends on engine temperature) and the fixed size of the throttle body bore. However... There is an adjustment screw in the throttle body, and once set at the factory, it's sealed away under an aluminum bung or plug that's been tapped into the access hole. To get it out, first give it a tiny squirt of WD-40, or Liquid Wrench, or other such penetrating oil. Next, drill a small hole in the bung. If you're a purist, use a center punch first, but that really isn't necessary here. Drill in no more than about 1/8 inch (about 3mm). Screw a machine or wood screw into the hole until it's in tight. Pull on the screw with pliers to remove the bung. You will now find the allen screw that will allow you to make minor airflow adjustments to the throttle body, thereby changing fuel mixture. Note that this is a sensitive adjustment, and the BEST way to use it is with the car hooked up to a diagnostic smog machine, where you can monitor what you are doing via the numbers...
For More Information For additional information, history and buying tips on the Porsche 924, 944 and 951 models, there are several sources of information available to help you: Visit, and join, the Porsche 944 World Community at Excite. Join RennList, an invaluable online community of Porsche owners and enthusiasts. See my Porsche and More Links Page, with links to other Porsche and automotive-related sites. Also, see my Buying a Porsche 944 Page, with some info on what to look for, what to ask, etc. So, you bought a 944! This
page is related to my buying tips page, and is
specifically for you as a new 944 owner. Covers some of the
first and most basic things you might want to check (or fix)
right away.
|