jmayzurk

FYI, I just replaced the OE diverter valves on my '97 993TT with 70k miles. The right one was fine, opening with a few inches of vacuum. The left didn't open under vacuum, so it was effectively stuck closed. I disassembled this one, but the diagraphm appeared intact and in reasonably good condition. Obviously it has a leak of some sort, however. I replaced them with Evolution Motorsports valves (www.evoms.com).

While I'm in there, I'm replacing plug wires (due to age) and boost pressure sensor (occasionally getting wacky readings), and the MAF sensor. The dealer replaced plugs during 60k service. Anything else I should do while I'm here?

Regarding plug wires, the left side (cyl 1-3) wires were a snap, but the right side is a pain...there are two wire hold-downs (behind the fan and under the intake manifold) that are attached to the engine tin with screws. A real pain in the *** when you have to get them from a right angle and with only 1/2" of clearance above the screw. The factory couldn't have used hex-head screws?

Any tips? I'm going out to look for a shorter right-angle screwdriver. I considered removing the intake manifold, but hopefully that is not necessary.

Thanks,

-Jeff

911/Q45

New belts, belt tension sensor(if plastic rim missing), A/C bracket mod for belt access, large intercooler to throttle body oring, boost hoses(if not orange end), copper washers for power steering fluid hose banjo ends. Let us know if replacing the boost pressure sensor makes a difference, I've heard it doesn't.

Felix

What's that all about?

From the wiring diagram the boost sensor is only used by the digital display in the tach and not the ECU so I would predict no change to the car's running.

911/Q45

The original A/C bracket didn't leave enough clearance near the engine pulley to easily change the belts, so there is a TSB to file away a corner of it to provide clearance. I'm curious to see if the boost sensor change fixes the occasional gauge malfunction that many of us experience.

viperbob

You are not going to like to hear this but step one, lift intake. We usually drop the engine in the mounts as much as possible. Then loosend the intake runners into the rubber boots. Now lift up so you can gain access to those STUPID wire blocks on the back side of the fan.

jmayzurk

Thanks for your response, Bob. I just got to the point where I have all old plug wires out. What a tremendous pain in the ***.

I was able to get enough access after removing the top fan shroud. To remove the screws, I had to modify two tools: I went to sears and bought two mini-ratchets (the kind sold as screwdriver sets with 1/4" bits, e.g., http://www.sears.com/sr/javasr/produ...ubcat=Wrenches ). I cut the bits as short as possible and then welded them into the 1/4" socket in the ratchet.

It was still a pain but eventually I was able to get all four screws (when I reinstall I am going to replace with hex head screws). Finally, I had to loosen the top A/C compresor mount to fish the old wires out. Anyone have a link to the TSB for modifying this?

Is removing the intake as simple as loosening the six rubber boots and lifting?

-Jeff

Kevin

Jeff, it's nice see that you are being pro-active with regards to aging components. One other sensor that needs some attention is the cylinder head temp unit which is located on #3.. It is a pain to get.. But if you get a new clutch, keep in mind to replace it..

Another area of concern is oiled K&N air filters will degrade the performance of a MAF.. With the new unit use the stock air filters..

Yes it is rather simple to loosen up the hose clamps to the rubber hoses on each intake runner. However, you have to make sure that you do not knock a smaller vaccuum or pressure hose attached to the manifold..

viperbob

With the intercooler off, it is as easy as loosening those 6 clamps and carefully prying it up. Not a bad idea to spray some wd 40 in the boots with a screwdriver loosening the rubber and working it around. Also makes going on easier.

I just saw that TSB recently with a shaded area where to file. It was kind of funny in a Porsche sort of way as we never do anything wrong, but this is kind of a problem that means the belt won't come off unless the bracket is filed down. I'll keep looking.

911/Q45

TSB 9505 says to file away the lump on the lower A/C bracket next to the pulley and just below the attaching nut. Use a flat metal file and wear gloves! I have the TSB, so if you can't figure it out let me know and I can send you a Xerox or just ask the wrench at the dealer to let you look at the picture.