77 911 s randomly dies!!??

spinner37 · 06:30 PM

i just bought a 77 911s with 50,000 miles. i did a bunch of research and the car seems pretty solid but needs alot of TLC. it has the 11 blade fan on it so i am hoping the cylinder bolts have been done also. my problem is the car will randomly shut off. it starts right up, runs great, but will just die. i have been playing with the fuel air screw??? i think and can get it better but the idle goes up. it seems like it is not geting fuel??? any body experience this? it seems like it may also be a vacuum leak but i am still pretty new to these cars and the fuel injection system.... the car is a riot though, i have wanted one since i was 10 and 25 years later finally bought one!

John-1977911s · 08-20-2009, 11:31 AM

Spinner ~ just a word of advice regarding this message board.

An introduction goes a long way and so do pictures. There are a lot of experienced Porsche guys here willing to help.

My word of advice to your problem is since your injection system is off calibration; I would advise taking it to a local shop that knows these cars. Spend the 1 hour of time and have them set up the injection system. Once you know that's right trouble shooting the fuel system and ignition system is pretty easy.

By the way a '77 can be a very nice car despite what you may read.

Paulporsche · 08-20-2009, 12:21 PM

Welcome and glad to see you finally achieved your dream.

Some things to get you started:

You always want to make sure your ignition components are operating correctly before messing w/ your fuel injection. So check your plugs, points, wires , rotor and cap.

Make sure your fuel pump relay is making good contact in its socket. And check to see that your fuel pump isn't drawing excessive current.

Make sure your ignition switch is OK and that your key isn't causing the switch to turn itself off. Always put just 1 or 2 keys on the fob and no more.

Finally, if you have a Permatune CDI that may be your cause. There are many posts about owners of these units who had them stop when they heated up, only to restart later.

After you have verified all ignition items are OK, then move on to the FI if you have to. You should verify that your fuel pressures are correct and that your WUR is functioning correctly.

If you use the search function on this site you will find a ton of info on CIS running issues.

Keep us informed and post some pics of your car.

spinner37 · 08-20-2009, 06:59 PM

thanks! i will get some pictures in the next couple days. i will try to find a shop to set up the injection system. one of the plug wires is bad so new wires, plugs and cap and rotor are on order. i will look to see if i have a permatune cdi also and check the fuel pump relay, i originally thought it was a fuel pump issue..... i brought the car home today and washed it, it is/was a mess, interior full of garbage, but in pretty nice shape. whoever painted the car black did a bad job and it is all orange peel, kind of a faded rat rod look. outside is pretty clean now so i am working on the interior and waiting for my motor parts. i have built a jeep/rockbuggy over the years and just sold that. this car is really "rough" like my jeep but it is way more fun on the road! i drove it home on the highway at 70mph with no trouble, only stalled a couple times but it is idling high to help with the stalling. i plan to drive this as much as i can, but slowly fix it up as i do, mainly winter projects and drive it in the other months. i noticed tonight it sits a half inch high on the drivers side which is making me worried....... he also has smaller tires in the back, are'nt the back tires supposed to be bigger? sorry i didn't have an intro, but basically i am a mechanic/fabricator and love cars like this. i love feeling connected to the car and not isolated from everything, i really don't like new cars. i also drive a 97 VR6 jetta that is a little hot rodded

i really don't like front wheel drive though, so the 911 will fix that for me!

spinner37 · 08-22-2009, 08:02 PM

so i have about 3 hours driving the car, odometer is not working..... it really cleaned up, i filled it with 93 octane gas and tried to really twist the broken spark plug wire in. sooo, my new tune up parts will be here monday, but tonight it was really running pretty good, almost not even misfiring, and i also was able to turn the fuel screw back in about a turn to get the idle back down to about 1100, and it is not stalling out anymore! i think the car has been sitting for awhile until now. is the fuel screw the right way to adjust the idle? i will post some pics tomorrow. i rubbed out some of the faded black paint and it came out nice too. i am still cautious, but for 6 grand i am starting to think i may have gotten a deal.....i will be a regular on this sight, you guys are awesome! i used to be a very active member at www.pirate4x4.com when i had my jeep. these bulletin boards are the best way to meet people and learn about a new passion, mucho thanks!

Alan L · Alan L's Garage

Your idle screw is a BIG screw on the LHS of the throttle body.
Your mix adjust is a hidden 3 mm allen screw down a hole by the airbox system. Hard to explain - but I suspect you are going to need a manual at some time.
One thing you could do to get a rough idea of where the tuning should be is get a long 3 mm allen key, find the tuning hole and insert. Note where the allen key is pointing O'clock (make sure it has located/locked into the screw). If you go anti clockwise you lean it and vice versa. Engine warm and idling, rotate slowly one way - about 1/4 turn - the engine should respond. At the point it starts to stumble/get irregular, stop. Note O'clock. Now go other way til same happens again. Note O'clock. Now go to mid point. You will be close enough to eliminate tuning issues.
Next time it dies, if you can, pull a plug and see if spark. If so, and still not running, likely a fuel issue.
At that point the thread will get longer, but it is fixable and for a few hours time, should not cost a lot.
Alan

spinner37 · 08-23-2009, 04:29 AM

ahh, so i am only adjusting the idle, i thought i was adjusting the mix to change the idle....i will look for the 3mm alen, that tuning technique sounds really similar to tuning my dirtbike

i am considering a couple different manuals, i see the bentley is about 280 and comes with 3 books, but it talks about history and stuff so i was not sure if it was a service manual also. i have a bentley manual for my VW and it is very good. i also thought about the haynes manual but those usually are not that detailed....thanks for the tip!

Jesset100 · Jesset100's Garage

Read this
http://members.rennlist.com/jimwms/CIS/CIShome.html

Read and print these
How to setup CIS with no gauges

CIS Idle Speed and Mixture Setting Without an Analyzer

spinner37 · 08-23-2009, 09:02 AM

very helpfull! thanks, i will start on the cis when i get the ignition all set... i looked quickly but could not find the "hole" for the long allen wrench? any pointers on a 77 2.7, somewhere near the throttle body and air box??? today the car ran bad for aobut 20 minutes, then it cleans up pretty well.... it is 70 degrees out, so i need to do some tuning so it will run better cold....

spinner37 · 08-23-2009, 05:54 PM

is this an ac pump or the oil cooler???? here are some pics of the car too! interior looks nice after 4 hours of work

paint is rough, but livable for sure

spinner37 · 08-23-2009, 05:55 PM

oh yea, i am on the fence about the gold wheels...... i will get some better pics if it ever stops raining here in buffalo!

Alan L · Alan L's Garage

That is your air con compressor.
You have a rubber air box hat thing going between two intakes for your air - called a popes hat. The hole is mid point to the RHS of the popes hat. Your Fuel distributor sits further over to the RHS. It is in between, but adjacent to the popes hat. They are virtually touching each other. You cant really see the hole (there is a cast ridging around it). You have to do it by braille. But if in the right spot your allen key will drop in the hole by about an inch before it picks up the tuning head of the allen screw.
Alan

spinner37 · 08-24-2009, 10:27 AM

ok, so i found the fuel mix allen screw thanks to alan L's directions. i was not able to turn it though, is this normal? i was just using the short end of the allen, should i put a small pipe on it??? i am still waiting for parts, but the plugs are out and the gap is at .80 mm!!! factory they are supposed to be .50 mm, so this may be a problem also. all the plugs looked a little lean, the farthest one in on the passenger side is a little oily, might be indiacting a problem.... nayways, thanks again for all the help, hopefully the ups man gets here soon!!! oh, should i use the factory .50mm gap specs? the motor seems to be stock except for the exhaust and the thermal reactor things are gone....

Alan L · Alan L's Garage

Factory specs for plugs - it actually affects your timing slightly.
Long end of allen key down hole - usually have to insert on bit of angle then straighten the angle as goes down hole. Should feel it bottom out, then lightly rotate til feel it seat in head of adjusting screw. Orientate it so you can move it about 1/4 turn either way.
Alan

spinner37 · 08-24-2009, 06:22 PM

woohoo! car is running really good after tune up, no more misfire or running bad in general. it is idling at about 1100, if i go lower it wants to stall randomly again. the idle is kind of rolling, which i was looking into yesterday. otherwise, i am really happy so far, it needs some more tuning but it is really good right now. i get some bad exhaust noise at lower rpms, lots of booger welds....it also is ticking pretty loud on the driver side, it is loudest if you stick your ear near the wheel well, valve noise i suppose? i am planning on really going through the motor this winter, but am thinking i might adjust the valves sooner. the last thing i noticed, it oversteers in fast corners, which i was not ready for! maybe new tires are in order also??

thanks for all the tips, i will be a regular here and hopefully can help out some "newbies" in the future....

Alan L · Alan L's Garage

It should not oversteer, unless you are hacking it into corners. If you set it up gently and power your way thru the corner progressively, despite its age, it should be rock steady and leave most cars for dead. They take a bit of getting used too - 6 mths. Take some care early on and get the feel of it. It is like nothing you have driven before.
If in a month or two it still 'oversteers' you may like to get the alignment checked.
Probably valve noise - put screw driver on valve covers and place ear on other end.
It may, possibly, be a timing chain issue - put screw driver on chain case at rear of engine . See where noisiest. Most likely valve. Aircooled motors noisier than water cooled.
The car should want to idle well at 800 easily. As you tweek idle speed screw you may need to adjust mix screw slightly too. If engine sort of races then falls back on idle, too lean. If it loads up then comes right, loads again then too rich. Very small adjsutments - 1/16 turn.
Alan

Alan L · Alan L's Garage

If it does not idle better than this, maybe check the timing. The specs should be on a sticker on the alternator strap. It should tick over like a swiss watch eventually. They make a neat sound on idle, and full noise.
Take care getting used to it, or you will surely crash and burn.
Hard to tell someone how to drive it. But slow in fast out works best every time. Set yourself into the corner at a comfortable speed (this will increase as you get more used to it). When you can comfortably see your way thru the apex and the cornering line, start pouring the gas on. Progressively. Dont just nail it to the floor. The key is to keep it balanced and driving from the rear wheels. But you have to set it up right from the beginning to do it. Hit the corner too hard and you have to lift off halfway thru, expect problems (oversteer, big time) . Take it gradually or your dream will become a nightmare.
IMHO the reputation they have for going backwards around a corner is those people drive them like idiots and expect them to defy the laws of physics. They do better than most cars, but the laws still apply.
Regards
Alan

spinner37 · 08-25-2009, 03:51 AM

the corner it pushed through i went in at a fair speed and accelerated through the corner smoothly, the same as i do in my VW jetta vr6, which pushes corners because of front wheel drive. it was like the front is too light and wasn't getting traction in the 911, the car was stable and flat. it was a pretty sharp corner, 2nd gear about 20 when i went in, 45 on the way out. i will learn to drive the car safely, I am young but not that young

it handles better tehn anything ive driven so far, it just suprised me when the front end felt loose. i have to listen to the idle, i am not sure if it is racing and falling back or loading and revving up....now my wife wants to drive the car, i think i am going to just keep telling her it is not running right

T77911S · 08-25-2009, 03:59 AM

check into the ticking. it may jsut be an adjustment, but it could also be a rocker shaft coming out or an exhaust guide that is lose.

before making big adjustments, run a few tanks of gas with some injector cleaner through it. read up on CIS and learn some more about it. it sounds like it was a good thing you did not find the mixture screw right away. CIS in not complicated, but it can be very confusing at first.
it is very reliable and very good on gas. air leaks are its big weakness.

spinner37 · 08-25-2009, 08:12 AM

today my car is not happy. it started shutting down again, alot, and bucking at speed also. it had me on the side of the highway with no shoulder

it will start right up, fire to 1800 rpm, then shut right off. it might do this a bunch of times, or one time. then it might dirive fine, sememingly running good. it seems to shut down after i accellerate hard, then when i go to shift it is turned off. so, i am thinking fuel filters and fuel pump.i need to check timing and the coil but it does not seem electrical. i noticed the distributer will move up and down when i had the cap off and i am not sure if this is normal?when it is running, it runs good. i drove 20 miles down the highway at 70mph without a hickup. stopped for 15 minutes, then had a fun time getting home! yesterday it ran great, not stalling. i was thinking about more fresh gas and injector cleaner also, but if it is stalling so much i can't drive it too much. changing the idle today did not seem to help, faster idle is a little better, but still stalling.is the 3 book bentley manual the one to get? i thinkit is like 280 or something, but it mentioned alot aobut the history of porsche, is it a service manual too? i think i saw it on this site..... thanks again for any help, i will leave the fuel injection alone for now, it does not seemmlike the injection would cause it to turn off?