many Big Problems --- pics

[ZA11]

Hi Guys,

Had my very 1st 1980 911 Sc (converted to 964) for 1 month & found major issues.

1. Air-conditioning affecting Rpm:
Whenever the air-cond is turned on, the car will die in anytime ... on the slope, at the traffic junction ... I have been driving it with the windows down. The idle rpm is 1200 rpm & when I see it dropping below it, I know it's coming to die, & this has been a stressful ride. I don't think it's the air-cond faulty, as similarly when I switch on the headlights, the rpm will drop & the engine dies when I am in a standstill position.

2. Acceleration problem:
The speed at cruising (4th & 5th gear) at around 3000 rpm -- 3400 rpm. Is this too low?

3. Hot or cold start problem:
What should I do with it? It has no problem starting in the morning or the 1st start of the day. However, afterwards, (even rested for more than 2 hours -- engine should be cooled by then), the engine has problems starting. I have to try several tries, like minimum 3 tries with interval in between & depressing the acceleration slightly, then only it can start off .. with a coughing-like low sound & slowly come up to its normal throttle. It's very un-porsched liked of starting, & embarrassing especially with onlookers around.

4. Fuel:
There's this one helpful guy who stopped by & told me it was 'vapor-trapped' problem to the above. I googled & found that vapor has to do with the petrol type. 1st I used 98 RON (which research says it generate the most vapor), then I tried out 95 RON petrol, however, the starting problem doesn't go away ... by the way, it's always a question that what kind of petrol should I use for this old model car?


I got my car from a dealer & it had been sent to an exotic car mechanic for 'general' checking before handling over. However, plagued with these problems, I have to sort it once & for all to restore this beauty to its glory.

Appreciate if anyone can offer advice, THANK YOU.

[Rich76_911s]

#3 sounds like it is a problem with your starter. I know others have had this problem and it usually is traced back to a starter that is worn out. Do a search on hot start issues and I am sure you can find more details.

I can't speak for the other problems. But I am sure others will chime in and be able to help.

By the way welcome to Pelican, and beautiful car.

Rich

[ZA11]

Thanks Rich, the starter will be a great start off for my search.

Zinnie

[GrantG]

Problem #2 is a gearing issue. The gears in your transaxle provide a fixed ratio between speed and rpm. If you don't like the rpm in a given gear at a given speed, the only fix is to change the gearstack or ring & pinion (or use much smaller wheels/tires).

I think your numbers are probably normal, if by cruising speed you mean something close to the speed limit. If you want better accleration, drop down into 3rd gear and see if that helps

[silverc4s]

[QUOTE=ZA11;4221144]Hi Guys,

Had my very 1st 1980 911 Sc (converted to 964) for 1 month & found major issues.

1. Air-conditioning affecting Rpm:
Whenever the air-cond is turned on, the car will die in anytime ... on the slope, at the traffic junction ... I have been driving it with the windows down. The idle rpm is 1200 rpm & when I see it dropping below it, I know it's coming to die, & this has been a stressful ride. I don't think it's the air-cond faulty, as similarly when I switch on the headlights, the rpm will drop & the engine dies when I am in a standstill position.

2. Acceleration problem:
The speed at cruising (4th & 5th gear) at around 3000 rpm -- 3400 rpm. Is this too low?

3. Hot or cold start problem:
What should I do with it? It has no problem starting in the morning or the 1st start of the day. However, even after (even rested for more than 2 hours -- engine should be cooled by then), the engine has problems starting. I have to try several tries, like minimum 3 tries with interval in between & depressing the acceleration slightly, then only it can start off .. with a coughing-like low sound & slowly come up to its normal throttle. It's very un-porsched liked of starting, & embarrassing especially with onlookers around.

4. Fuel:
There's this one helpful guy who stopped by & told me it was 'vapor-trapped' problem to the above. I googled & found that vapor has to do with the petrol type. 1st I used 98 RON (which research says it generate the most vapor), then I tried out 95 RON petrol, however, the starting problem doesn't go away ... by the way, it's always a question that what kind of petrol should I use for this old model car?


I got my car from a dealer & it had been sent to an exotic car mechanic for 'general' checking before handling over. However, plagued with these problems, I have to sort it once & for all to restore this beauty to its glory.

Appreciate if anyone can offer advice, THANK YOU.

Zinnie,
Welcome to PelicanParts, great looking 911 you have, I bet it's a standout in Singapore! (That's where you are, right?) Love the color.
Anyway, your problems numbered 1, 3, and 4 all sound like they could be related to the condition of your CIS fuel injection system. It is a very complex system, with many vacuum hoses and many valves and regulating parts that are now hmmmm 28 years old!
If it were me, I would try to find a good early 911 mechanic there that is comfortable with CIS injection troubleshooting and tuning. It may just need a good cleaning and adjustment to make all of those troubles go away. Good luck, enjoy the experience as you move along with that great looking car.

BTW, for #2 - cruising in top gear should be around 20 to 22 mph per 1000 rpm. These engines are quite happy in the 3000 to 6000 rpm range, enjoy!!

[Bobboloo]

Originally Posted by ZA11

1. Air-conditioning affecting Rpm:
Whenever the air-cond is turned on, the car will die in anytime ... on the slope, at the traffic junction ... I have been driving it with the windows down. The idle rpm is 1200 rpm & when I see it dropping below it, I know it's coming to die, & this has been a stressful ride. I don't think it's the air-cond faulty, as similarly when I switch on the headlights, the rpm will drop & the engine dies when I am in a standstill position.

Possibly the voltage regulator. Have a shop check your charging system.

Originally Posted by ZA11

2. Acceleration problem:
The speed at cruising (4th & 5th gear) at around 3000 rpm -- 3400 rpm. Is this too low?

No. Just downshift to accelerate. These motors don't mind being wound up to accelerate.

Originally Posted by ZA11

3. Hot or cold start problem:
What should I do with it? It has no problem starting in the morning or the 1st start of the day. However, even after (even rested for more than 2 hours -- engine should be cooled by then), the engine has problems starting. I have to try several tries, like minimum 3 tries with interval in between & depressing the acceleration slightly, then only it can start off .. with a coughing-like low sound & slowly come up to its normal throttle. It's very un-porsched liked of starting, & embarrassing especially with onlookers around.

As mentioned before. Your CIS injection system is out of calibration. You can only troubleshoot this problem with pressure gauges so either you buy the gauges and do a lot of research or you find a mechanic with CIS pressure gauges and have them do it.

What often happens is the WUR goes out of calibration over time and leans out the cold start so then someone turns the idle mixture to make it richer for cold starting which works fine except then the warm start is out of calibration. Also the fuel accumulator is possibly faulty.

At any rate take some time and find a mechanic that's well versed with CIS injection. That's Porsche years 74' thru 83' in general or a Mercedes or Volvo mechanic that knows the cars from the 80's.

Originally Posted by ZA11

4. Fuel:
There's this one helpful guy who stopped by & told me it was 'vapor-trapped' problem to the above. I googled & found that vapor has to do with the petrol type. 1st I used 98 RON (which research says it generate the most vapor), then I tried out 95 RON petrol, however, the starting problem doesn't go away ... by the way, it's always a question that what kind of petrol should I use for this old model car?

This is not a vapor lock problem.

[ZA11]

Originally Posted by GrantG

Problem #2 is a gearing issue.
I think your numbers are probably normal, if by cruising speed you mean something close to the speed limit. If you want better accleration, drop down into 3rd gear and see if that helps

Hi Grant, Thanks for the idea of checking the gear out. Will do that. For 3rd gear, it can go beyond 3500 rpm

[ZA11]

[QUOTE=silverc4s;4221509]

Originally Posted by ZA11

Zinnie,
Welcome to PelicanParts, great looking 911 you have, I bet it's a standout in Singapore! (That's where you are, right?)

Thank you, Bill. I googled to this site & found out that it's great with 911 parts ( I don't need ebay anymore) & incredible expertise who love what they are doing with their Porsche.

Bingo. Uhm.. impressed.

Mine is not that standout though cos here is full of new ones ... I can only afford a really old one, just hope to gain some knowledge to save it up to its fully working condition. A good pre-owned car dealership which I saw on the newspaper the other day:
http://www.autoincsports.com/Directory.htm ... I missed out this one. I don't look at new ones, it really cost lots lots of $ & yet there are quite plnety of the news ones on the road ....
http://www.porsche.com/pap/_singapore_/models/911/

Ok, CIS injection troubleshooting and tuning , will do!.... Thanks, new idea to me. I all the time thought it was more of a hot start problem & it puzzled me with its behaviour.

[mca]

Couldn't his warm start issue be do to a faulty fuel accumulator?

That would be the first place that I would look. It is mounted next to your fuel filter.

[ZA11]

Originally Posted by Bobboloo

You can only troubleshoot this problem with pressure gauges so either you buy the gauges and do a lot of research or you find a mechanic with CIS pressure gauges and have them do it.

What often happens is the WUR goes out of calibration over time and leans out the cold start so then someone turns the idle mixture to make it richer for cold starting which works fine except then the warm start is out of calibration. Also the fuel accumulator is possibly faulty.

At any rate take some time and find a mechanic that's well versed with CIS injection. That's Porsche years 74' thru 83' in general or a Mercedes or Volvo mechanic that knows the cars from the 80's.

Hi Bobby,

Thank You very much for all your detailed input. Ok, checking the voltage regulator is a great idea. I only thought of maybe the rpm needed adjustment which I read from some articles ... however, it sounds unlikely here ... as my 1st car hatchback pulsar (cheap & good for a student then) had powerful air-cond & the engine never failed to start even it was switched to the max.

CIS injection with a good mechanic ... ok.. THANKS A LOT again.

Also dismiss the vapor-lock theory so that I won't mess with the fuel. THANKS.

When i tried with 93 RON, I did notice the power loss. Better just stick with 95 or 98.

[ZA11]

Bobby, also thanks for your assurance that I could down shift to 3rd gear!

[ZA11]

Originally Posted by mca

Couldn't his warm start issue be do to a faulty fuel accumulator?

That would be the first place that I would look. It is mounted next to your fuel filter.

Hi MCA, Thanks ... good to check for it 1st.

Your break-in video is amazing ... I envy how powerful & smooth it goes ... my car is pretty shaky ... feel like a bumpy ride.

[ramonesfreak]

the person that told you this was a "vapor-trapped" problem, was most likely trying to describe what happens when your fuel accumulator is going bad....since the purpose of the fuel accumulator is to maintain pressure in the fuel system to prevent fuel vaporization while the motor is not running

2 hours is not really considered to be "cool"...more like 5 or 6.....which is why the car starts ok in the morning

thus - i would replace fuel accumulator. i did mine last month. they dont last forever and 28 years means its quite old

[ZA11]

Thanks, you guys are great ... with all your help, I can see the light now ....

Will let you know if it's totally fixed ...

Zinnie

[DRACO A5OG]

Oh ZA11,

She will never be totally fixed. Just remember is a work of love, be patient and do not over torque. Get the Bentley Guide, you will be amazed how little torque she needs to keep her together. The beauty of our cars is that PAG over engineered alot of things on them which makes them so durable.

Take care and see you around on the Board

[raj911]

Hi ZA11,

Fellow Singaporean. I can't help you out with the tech stuff, but I can give you advice on where to go to get it fixed. Who takes care of your car now? I used to have an SC and sent it to quite a few second rate places, they messed up my car and I sold it out of sheer frustration.

Bought a 930 (with a few problems) from the same place you got your SC soon after. This time a few people on this board recommended Andy Tatlow at Flatsix. He sorted out my 930 and it is running like a champ! Granted, he's not cheap, but his knowledge of 911s is second to none. Pay him a visit. PM me for his number and address. We can meet up for a drive once you get your car sorted.

Cheers