Idle issue/hot start

[opata]

Hello, I'm new to the 911 world and I'm still trying to get my 80SC to run right. It seems to have a mind of its own. I bought it a few months ago after it sat for 3yrs. I got it running but I am having idle issues. It will start but will not idle until it is warmed up. Which I see as a common issue for a car its age. Then after driving it for sometime it doesn't want to start. When I let it sit a few minutes it will start but will not idle. I am assuming this is a hot start issue. I have read and read.....and most point to the fuel accumulator. Will part # 911.110.197.01 work on an 80? I know it calls for part # 911.110.197.02. Which is alot more expensive. I have read on the form that his will work... and some think it might not. Or perhaps I am pointing in the wrong direction. I know it could be many things...WUR.... I replaced the fuel pump and check valve two weeks ago. Other things I have done: Removed fuel tank and had it cleaned, removed and cleaned the injectors (blew compressed air through them)....I know not scientific. New plugs, plug wires, cap, rotor. It runs 100% better than it did. Also, I had to adjust the mixture and idle screw to get it to run as good as it does. Could turning the mixture clockwise thus increasing fuel (rich) indicate a fuel pressure issue? I know this could also indicate a vaccum leak? Sorry to ramble...I will purchase the CIS tool from JC Whitney soon. Just don't want to throw money into the wind. This is my first 911. It doesn't seem to have all that much get up and go? It’s like an 84 944 I once had. It really doesn't have power in the low RPM range. It starts to take off above 4K. Am I silly for thinking this? I'm sure there will be other post from me as I learn the air cooled world of the 911. Again thanks for any advise! I really appreciate the help! You people are great!

[Paulporsche]

Welcome. Sounds like you've done quite a bit to get your new car running correctly.

Since you've done a lot to the ignition, which has improved things, I would get the CIS fuel pressure gauge and check those pressures next. I didn't see where you are located, but you will want to check the control pressures from cold up through warmup. It's possible by varying the mixture you are correcting an improper setting, but it's also possible you are trying to mask a problem, such as a vac leak or incorrect control pressures.

If you search you will see there is a lot of info on doing the tests, and how to find vac leaks.

Good luck and be sure to post the test results. In the meantime, make sure the diz is operating correctly and check for leaks.

[sc_rufctr]

You should check the WUR first. Check to see if there is power getting to its electrical plug with a multi meter.
Also check the hoses on the WUR for leaks.



Also... Your car should have more get up and go than an 88 944. Check the distributor and ignition timing.

I know you cleaned your fuel tank but it may be worth running some Seafoam or similar product through the fuel system to ensure it's really clean.

A good SC should be a great drivers car.

[opata]

Hello, thanks for the advise! I'll order the tester soon. How do I check the dizzy? I've read posts about it but don't quite understand?? I've sprayed carb cleaner on hoses ect. to see if the idle changed. It didn't. Also, Do you rotate the distributor just like any other to set timing? Is the electrical to the WUR measured in ohms? Sorry, I have so many questions? Thanks!!!

[Walter_Middie]

How do I check the dizzy?

A good first check of the dizzy is to see if the advance is working correctly. Do you have a timing light? Start the car and check the timing at idle. Now, while watching the timing, reach over and rev up the engine. You should see the timing advance. Rev it up high enough (4,000 to 6,000 RPM) and you will see the timing advance to a certain point and then stop advancing. The timing where it stops is the total advance. You should have a spec for your car that includes idle and 6,000 RPM timing. The check for total timing at 6,000 RPM is the most important for performance. If your dizzy is not advancing correctly, you won't get a combination of correct idle timing and total timing. If the idle timing is off a little, and the total is OK, then don't worry about it. But if the timing doesn't advance much from idle, that can be a sign that your dizzy is dirty and not moving freely.

[ossiblue]

Lots of good advice given. You have to stay on a planned path and check/repair one aspect of your problem at a time, otherwise you'll go crazy.

When I got my 73.5T with a rebuilt 2.7, I had the same problem of a car with no power. Here's what was done. First, valves were adjusted. Second, all ignition components and timing was brought into specs. Third, CIS was studied, beginning with system pressure checks (which were way off, requiring rebuilding of the WUR), inspection of cold start components, and thorough check for vacuum leaks--of which there were many. Finally, after all the above was inspected, tested and repaired, the fuel mixture was set with a gas analyzer.

I'd suggest you follow a similar, logical path, working on only one aspect of the problem at a time (spark, fuel, compression--that's all it takes for an engine to run.) The most complex part is the CIS system, but there is an abundance of information and help on this board to get you through. Bottom line, my engine has way more power than I imagined, and runs smoothly. Yours will do the same.

[opata]

Hello, thank you for the wealth of information! I will get a timing light. I've always taken my cars into a shop a friend owns. This however seems to be a process over time. Plus I really want to understand the working of the car. Again thank you for the info!! I'll keep you posted as to the progress.....Thanks!!!!