993 Typical problems

06-23-2003, 12:07 PM

I've heard that the early 993s have problems with the wireing loom (don't know what that's about?) and that some 993 owners experience high oil consumption. I also hear about creaking windshields and that leads to my question:

What is this all about?

Will any 993 creak or is it only a problem on certain years or models (Cabrio, Targa, Coupe)? What is the problem caused by? Bodywork tolerances, flexing or...??

What other problems are known on 993s, if any?

motion · 06-23-2003, 12:37 PM

There's a well-known problem with carbon build-up on the valves. Occurs mostly on cars with 50,000 miles or more. The check engine light comes on. $4500 to fix. Wiring loom problem is only with 95s and some early 96s. Its a free warranty repair. Haven't heard about high oil consumption. All in all, there are some fairly serious problems with these cars. Kind of surprising, given the reliability of the 3.2 series.

LeeH · 06-23-2003, 12:39 PM

The current Excellence has an aticle on buying a 993 that mentions some common problems.

Rick Lee · Rick Lee's Garage

I hope I have a head start on the carbon build-up issue. I drive my car very hard and often. At 31k miles, I hope I'm not starting too late.

john_colasante · 06-23-2003, 01:28 PM

As far as I'm concerned the carbon buildup is a non-issue. It does not effect performance at all. There are passages in the heads of USA version 993 engines that permit auxiliary air to pump into the exhaust ports at startup. Carbon can build up in these ports and then you get a check engine light because the O2 sensor detects a mixture variation in startup. But, the problem does not effect the running of the engine at all other than a few seconds at startup.

I am waiting for someone to come out with a workaround to "fool" the computer into thinking the passages are not blocked. I do not have the light now but if I get it you can be sure I'm not spending $4500 to blow out some pretty useless passages. This carbon problem is not the same as a carbon buildup on the valves or pistons which is more serious and is NOT a problem with 993's. I do not think this problem effects '95 cars because they have a different computer system that does not sense the failure in the aux air system.

adscab · 06-23-2003, 02:23 PM

My 97 suffered from this and the PO had a "top end" rebuild done under warrantly at a cost of $5K. I guess I'm good to go for a while.

pbs911 · pbs911's Garage

Why the carbon problem with the 993? Is it that the original purchasers just don't drive the car hard? Or does it have to do something with the new lifters? I heard the 993's also go through rear tires quickly, especially the 95's.

I also heard that the creak is only common on the 993 Targa.

Bill Verburg · Bill Verburg's Garage

It's only an issue w/ US '96 on cars which have OBDII. As John said there is an electric pump used for Secondary Air Injection which operates for a few seconds on cold starts. 2 issues w/ this subsystem are (1)rust, the tubes carrying the SAI to the heads rust easily and (2) carbon buildup in the SAI passage near the exhaust port. Either will prevent SAI from reaching the exhaust which triggers a check engine light because the pre and post O₂ sensors are out of synch w/ each other.

9XI · 9XI's Garage

Surprised no one has mentioned the rear tire issue. Early 993s ate rear tires up big time, correct?

nostatic · nostatic's Garage

I had heard the window issue was on coupes also (seal too thin?). The wire harness is a known issue that PCNA has grudgingly admitted to and will fix for free. The rear tires supposedly last about 10K or so, and I believe '95 was the worst. Has to do with the newer suspension?

billh1963 · billh1963's Garage

If you're really interested in 993's I would suggest you check out the 993 FAQ on Rennlist in the 993 forum. There's a lot of misinformation already flowing on this thread so you may want to get the true story "straight from the horse's mouth". 993's have their share of problems like every other P-car series...no worse than any others and certainly better than some.

Can you tell I'm a proud 993 C4S owner?

nostatic · nostatic's Garage

not sure where the misinformation is. The carbon buildup and wiring harness are mentioned in the faq. A quick search turns up info on the window creak (http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic;f=3;t=007263), and rear tire wear is here (http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic;f=3;t=009507).

deltajetfixer · deltajetfixer's Garage

Quote:

Originally posted by nostatic
not sure where the misinformation is. The carbon buildup and wiring harness are mentioned in the faq.

The "misinformation" is probably the tone of the thread? I'm just guessing as I've read and re-read it in hopes of finding offense

95's are immune to the check engine light caused by the secondary air injection ports becoming clogged. The OBD I on The Beast is just too ignorant to know it's constipated.

The wiring harness is finally a recall item. As far as I know, myself and another fellow on the Rennlist Board were the only ones to pre-empt the recall and replace the harnesses ourselves. I have been reimbursed by PCNA for my cost of the harness but since it was a DIY, not the labor...too bad as The Book says 10 hours.

Finally, the tire wear issue. I'm running stock 16's and have 13,000 miles on them. Looks to me like I've got another 13,000 left. Perhaps the guys running 17's and 18's with different alignment settings are experiencing the heavy wear? I dunno...

Almost forgot! The Squeaky Windshield! Sorry...don't have it and if I did, probably couldn't hear it over the air/oil cooled symphony in the rear!!!

billh1963 · billh1963's Garage

You're right, nostatic..."misinformation" is too harsh. My statement was intended to head off statements that were too general or derived from hearsay.

Tire wear was a problem on '95's. My '96 got almost 30K on the rears before they were replaced.

There are lots of thoughts on the carbon build-up. There is some consensus now that it is not a problem that needs to be fixed.

Wiring harnesses are issues on '95's and early '96's.

I stand by my assertion that anyone serious about a 993 should visit the very active 993 forum on Rennlist.

I apologize if I offended any contributors to this thread

nostatic · nostatic's Garage

no offense taken...if I had as sweet a 993 as you, I'd be on the lookout for potential bashers too

I (like many here) lust after a good 993 (S in particular), but I think they are just like every iteration of 911...great car with a few "issues".

I"m still interested to see if the 3.6 engines end up being as long lived as the 3.0. We're starting to get decent numbers of higher miles cars, so time will tell. I suspect that owners that kept the engine cover on and didn't drive them "properly" (ie shift at 3K, putter along) contribute to some of the problems seen. The thing is I'm not sure how much the demographic has changed...I suspect that the percentage of "enthusiasts" that are *first* owners of the car has always been rather low.

I'd also agree about the Rennlist being active with 993 owners. This place is more heavily skewed towards 3.2 and older cars, although it seems like a significant number of pelican owners are now buying 993s. I"m sure we'll see more 993-specific posts here as the migration increases.

88911coupe · 06-23-2003, 06:07 PM

I have also heard that the valve guide issue affected some 993's. I wonder if JW has seen any 993's come through with this issue. I have a friend with a '95 993 and he's getting the wire harness fixed for free but getting it scheduled has been very difficult (he's in LA)
I definitely feel the 993 is my ultimate 911 dream.

Rick Lee · Rick Lee's Garage

I had my wiring harness done last week and all I've noticed is that my passenger seat won't move forward or backward anymore. I'm not too worried about anything else. When the tires go, then it will be time for 18" wheels and some phat Yokos. My a/c kicks as$!

plain fan · 06-23-2003, 06:23 PM

You know after looking at the 959 pics from this year's parade I don't see why Porsche didn't go straight to the 993 look after the 74-89 911 styling. Every time I look at a 959 it just reminds me of a 993.

Rick Lee · Rick Lee's Garage

Speaking of OBDII, here's a cool shot of my fault codes getting checked for free at our tech session on Sat.

Rick Lee · Rick Lee's Garage

Here's another gratuitous shot of my Carrera and 993 in from of BW911's white '88. Can you tell I'm finally learning how to post photos?