944GreenHorn

Hey guys and gals,
New to the group so I figured a first post was in order.
I'm not much of a mechanic. I change oil, do brake jobs, plugs, etc. Mostly small stuff. My dad has fed his family by working as a mechanic for 40+ years, so I have a good grease mentor.
A month ago I bought my second porsche in 20+ years. An 87 944 NA with automatic transmission. I picked it up for $3K locally. The body is near mint, and the interior matches. I got the usual, "oh yeah, I maintained it like the Mona Lisa." and it turns out to be anything but. It runs decent and has some issues that need to be ironed out, but I have been using it as a daily driver or 100+ miles twice a week.

So much for the intro... I figured I would add my experience with the rough idle probelm.

She has had a rough idel since I got her. I did the research and came up with the usual ISV, throttle position switch, etc diagnosis. As I was taking off the intake manifold, I noticed that a vacuum line running to the fuel pressure regulator had snapped off. I also noticed that one of the intake gaskets had ruptured and pulled apart.
I also tested the ISV using the jumper method. It tested out fine. It even looked like new inside.
I made a trip to the parts store and bought new vacuum line. I'm replacing it as we speak.
I ordered 4 new gaskets and will install them on Monday when they come in.

I guess the thrust of this post would be to bring attention to the possibility of the ruptured gasket as a problem for some of the rough idles out there. I read a post here on the forum about someone else who had the same problem. I guess that diagnosis should be added to the list of possible causes.

I'll post results when I get the pieces back in place. Thanks for all the help guys. I'm sure I'll have MANY questions in the future.

Grandpa#3

Hi Greenhorn, A BIG WELCOME TO THE FORUM. The first question everyone wants to ask, so I'll get it out of the way. When were the cam, balance belts and all rollers changed out? The next is the water pump changed? Any maintenance records with the car? Slush box is expensive to repair along with the Damper ($1200). The steering wheel, you can resew the leather using a cross stitch and redye it, good as new if no worn thru spots. Winter Project... As you have done your research you must know about clark's garage. com. Read all the forums TECH INFO/ARTICLES and do a SEARCH for anything else.

http://www.clarks-garage.com/shop-ma...ure-index3.htm

http://www.texasblake.com/porsche/index.html

http://www.arnnworx.com/Policies1.htm

http://www.leatherique.com/index.htm

Cheers,
Larry

944GreenHorn

Glad to be aboard Larry.
It does have some pretty extensive maintenance records. In the glovebox there is an entire manilla envelope full of garage receipts and work orders. I have been keeping my own records as well. I am trying to trudge through and see what has been done and what hasn't. When I bought the car, they assured me that the water pump and belt had "just been changed"...whatever that means. I'm planning on putting on a new pump and belts this spring.

Since I have had the car I have done the following:
I rebuilt the driver's side balljoint (I have the parts for the other side...I'll do it sometime after Christmas).
I have replaced brake pads all around.
Installed a tune up kit (wires, rotor,button, cap, and plugs).
Installed new air filter.
Oil change with full synthetic (new filter of course).
Added Optima battery.
replaced hood struts.
replaced rear hatch struts.
replaced winshield wiper arms.
replaced the rear hatch seal and a few other minor rubber pieces.
replaced a broken wind defelctor hinge.
replaced missing "944" emblem on back.

As you can see, it was all major surgery but they were small things that I could do easily and still feel I was moving forward.
I'll get back with some of the major info as soon as I find it in the garage records.

Thanks for the links.

Mike C.

A vacuum leak can certainly cause a rough idle. It sounds like you will have no trouble converting this car to a standard transmission....

Grandpa#3

Hi, Sounds as if you have been busy as a bee. The only real difficult to change out are the Speed and Reference Sensors. You have soak them with Kroil for a few days and try to wiggle/pull them out. A lot of guys have broken the mount bracket to get them out. One thing to remember working on the rear engine is to cover the inspection hole on the bell housing with tape. Where bouts do you live?

Cheers,
Larry

944GreenHorn

Larry, I live in TN. Yes, I have been busy. You know how it is when you have a new woman in your life. :P
So Mike...why on earth would I want to go and do that??

944GreenHorn

Just wanted to update the situation.

I fixed the rough idle.

While working under the hood, not only did I find the gasket problem mentioned above, but I also found the hard vacuum lines going to the fuel regulator had snapped off under the intake where I couldn't see them. yet another problem added to the mix.
I replaced all the vaccum lines along with the gaskets and rebuilt the injectors while I was there.
She runs like a champ now. I think it may actually be firing on 4 cylinders now. :P

So, observations from my experiance with rough idle....

1. check ALL vaccum lines (even the little parts you can't see).
2. check your intake manifold gaskets. Listen with a length of hose if you have to.
3. Check you idle control valve.

Mike C.

It's no secret that these cars aren't rockets (the NA's that is)... a stick is less wasteful of the power that is there and much more fun to drive. Just keep an eye out for a 5 speed parts car.