Help!!

[rhauger]

.... I just bought my fiance a 1977 Porsche 911 (2.7). It is completely reconditioned outside of the engine. The engine has right under 130k miles and barely leaks. The car is sweet, but get TERRIBLE fuel economy (est. 12-14mpg?), idles unevenly and the exhaust is terrible! Not knowing any better, I thought it was a O2 sensor... apparently it doesnt have one! Does anyone have any suggestions on how to fix? where to start?

Thanks!!

Ryan

[Oh Haha]

You need to get it to a Porsche tech that knows their way around the CIS fuel system of that era.

While certainly DIY possible, the system takes some specific tools and techniques to set up properly.

Have you checked the basics like spark plugs, cap and rotor. air filter?

[rhauger]

Hey there,

Unfortunately,

I dont have anyone close at the moment. I am located in the middle of appalachia and have very few specialized mechanics in the region. I am looking for a few DYI tips before I start the hunt!

Thank you

[Paul K]

Wayne is right on. I suspect it will be worth your while to haul it to a specialist.

[HarryD]

Hi,

Welcome to the Best Porsche BBS on earth. While a bit fiddily, the cars are actually very DIY friendly. You will need to get some manuals to know how to work on and, of course, vist here often.

Also, it is customary to psot some picutres of your ride so we can enjoy what you have.

Most common problems have been discussed to death and a search will turn up a few threads that will get you back on track.

Ypou will need some repair manuals. For your car there are really only two manuals available: The Haynes and the Factory manuals. Our host Wayne Dempsey also published a book called "101 projects for your Porsche". You will find it helpful as well.

I am assuming you have the Stock CIS System on your car (if you upload a picutre of your engine room, we will be able to tell straight away). If so, for your running problem, before you start throwing parts at the car. do some reading on how to diagnose and adjust the CIS. You will need a few specialzed tools (a CIS fuel Pressure tester).

Before you start fiddling with the CIS, be sure you car has a fresh tune up (points, rotor, cap, sparkplugs), the timing and dwell are set correctly, the valves are properly adjusted, and verify (and repair) you have no instake system vacuum leaks. Once you get these items squared away, you can start checking the CIS System itself.

Do a search using the terms CIS and your specific symptoms. Look for threads posted by Grady Clay. There are other members who are equally knowledgeable. You will be able to tell when you read the posts.

During this time several makes of cars used CIS and a good shop who is familiar with CIS should be able to help you with the diagnosis. I know Volvos, Saab, Mercedes and other makes used CIS so you may find someone who can help you out.

while you find someone, this chart may help you isolate some of hte issues:

Pelican Parts: 911 Tech Info - CIS Troubleshooing