CIS Hard Cold Start - If You've Ever Had This Problem PLEASE READ THIS

[RarlyL8]

I "stumbled" across an odd (to me) cure for an old problem.

My '78 930 CIS engine has been slowly developing a hard start problem for over a year. The start time degraded to the point of taking 20-30 seconds of cranking to get the motor to "put put put" to life.

I tried everything. Checked for vacuum leaks, tweeked on the WUR, played with the AAV, you name it I did it. I could find NOTHING wrong with the CIS components.

Well a month or so ago I had to remove the engine for a tranny fix. When I put the engine back in it would not start. Not possible, I had connected everything as it was. To make a very long and aggravating story short, after removing half the engine to check out the fuel system and cold start components I moved back to the electrical.

Pulled a plug and hung it out to watch while cranking. I had no spark.

What the he!! was going on? After checking and re-checking the electrical connections I tried something not obvious, at the insistance of a freind. "Put the key in the run possition and jump the starter". Why do that, my problem is due to something I screwed up while putting the engine back. WRONG!

I turned the key to run and jumped the starter. THE CAR FIRED AND RAN. This engine had not fired and run on the first hit of a key in 2 years. Turns out the elecrical portion of the ignition switch had worn out to the point that the hot contact at start was impeding the current flow. There was enough juice to start the car when the engine was warm but not very well when cold.

That just ain't right. Living with 30 year old CIS components is dificult enough without the 30 year old electrical components joining in.

So I got out Wayne's trusty 101 Porsche Projects book and turned to Project #91 - replacing the ignition switch. One line caught my eye - "you may be able to reach the screws and save time". I made a tool to do just that. In 30 minutes my car was back starting like she did when new.

Moral of the story? Don't be so quick to blame the CIS.

Sometimes you're the statue, sometimes you're the bird. I've been the statue for over a year. Tonight my freinds I got to be the bird.

[2.7RACER]

Nice tip.
Thanks,

[Paulporsche]

Good work, and chirp chirp!

[Mysterytrain]

very nice..

[Split50]

So whats the spider in the jar for?
Did you send it in with the screwdriver to undo the screws?

Tim

[RarlyL8]

The spider, a female black widow, is my current garage mascot. Those things are all over down here. Keeping one in a jar reminds me that when your car sits in one spot for a month you should look up under the dash with a flashlight before stickin' your fingers up there.

[2.7S]

RarlyL8,

Way .

My P-car has been suffering from what appears to be a cold start issue since this last December. She starts fine on warm days, 60 and above. Turn the key over and she comes to life instantly. On colder days forget it.

However, two weeks ago I discovered a little trick when trying to get her started on a cold 40-degree morning here in So. Calif. After cranking her over a couple of times, I opened the lid to the engine compartment and turned the key to the on position to see if I could hear all of the correct sounds when the key was on. I listened and was able to here the correct sounds. Rather than just reaching in and turning the key off I decided to jump in and turn the key to the start position, she fired right up. Sunday morning was just as cold, so I ran outside and tried my new trick. I turned the key to the on position and counted to 45 before turning the key to the start position. It worked, as soon as the key was in the start position she fired right up. I’ve tried this five times since and it has worked every time.

I was thinking it was the warm up regulator (WUR), but after reading your post? I would like to be the bird as will, but that honor will have to go to my mechanic, as I have enough irons in the fire right now. If I’m lucky she’ll be at the shop by 3:30 pm tomorrow.

I must be patient.

Regards,

Larry

[Wayne 962]

Neat post. Love the sticker and the reference to the book!

-Wayne

[RarlyL8]

My pleasure Wayne. You're order guys are top notch. Every time I place an order it is on my doorstep in 2 days with no issues. The Porsche dealer hear in town wanted $90 for that ignition electrical module and 2 WEEKS to get it in.

The 101 projects book is great! I bought one of the first run copies (with the autograph) several years back. It is a really good complement to the technical manuals that don't get into the real-world details -- like the possibility of using a special screwdriver to take out that module.

Larry, it sounds like your fuel system is not holding pressure. There are a couple of check valves and the fuel accumulator that you can take a look at. A CIS pressure tester will confirm if that is your problem.

[Cipotifoso]

RarlyL8,
Your experience and info may be just the thing to solve my persistant problem of cold starts. I just need to test it to see if my slow cold start is caused by the same problem as in your car. Since I've never jumped the starter before, could you detail how you do this before I screw something up?
Thanks, Dave.

[Rex Walter]

RarlyL8,

It's always good to fix a problem that has been nagging you for a while. When my ignition switch was giving me problems in the start position, I took it apart, and found that Porsche put a couple of extra contacts inside, and I simply changed over to one of the unused contacts, and it has been no problem ever since.

I also just fixed a "CIS problem" that has been giving me problems for several years. My symptoms were, loping idle (too rich at idle), the car would stall out on left hand turns, and it was getting harder and harder to start - hot or cold. The troubleshooting charts say to check for leaky injectors or adjust the WUR. Turns out I had a weak fuel pump. A new (and very expensive) fuel pump has fixed all my problems. I now have a smooth idle for the first time since I owned the car, and it has not died in a left hand turn since the new pump. I don't understand this last one - I can only tell you that it did it consistently before - and not once since.

P.S. I see a few of the people that help those of us with CIS have chimed in here - I'd just like to say thanks for all the past help.

Rex

[Sunroof]

Same thing happened to me with my 73.5T. What I hated about this was laying on my back with a pillow on the brake pedal working on that top screw that was a Bit#h to get to!! I had to fabricate a tool (small screw driver bend with a 90 degree angle to reach it. It turned out Rattlesnake came ot the rescue and helped me out.

A word of cautiion to those who will ever repace the electrical portion.....you have to disconnect several wire bundles (light, turnsignal, etc) to be able to get to the switch comfortably. LABEL THESE AND WHERWERE THEY CAME FROM. If you replace them in the wrong locations, all hell breaks loose....

Bob

[Kroggers]

How and where do you jumped the starter??

[Miguel Antonett]

Thank you Rarly, great hint, great board!!!!!!!!!!!!!!!!!!!!

[RarlyL8]

You jump the starter from the main power terminal (large bolt on starter) to the yellow (solenoid) terminal. I used a remote start switch made for the application. You can just as easily use a large screwdriver.

To verify that your ignition switch is the culprit you put the switch in the "Run' position that the key snapps back to when you start the car. You should hear your CDI box and fuel pumps running. Then you jump the starter. If the engine starts or makes a real good attempt at it you probably have your answer. To verify you quickly turn off the engine (so it does not warm up in any way) and try to start the car using only the ignition switch. If it does not start the problem has been isolated to beween the switch and the starter, most likely the switch. I did this manuver 3 times to be absolutely certain (and not waste any more time and money on a wrong diagnosis).
Using a conductivity meter will not work well for this problem. The switch still allows electricity through but not the full 12V needed to fire the ignition while firing the starter. My starter spun like a champ but no spark.

I will try to get a few pictures for you and post them on this thread a little later.

[Cipotifoso]

RarlyL8,
Your description on jumping the starter was sufficient to accomplish the job. I had a remote starter switch out of a Sun tune up kit that I got years ago and hooked it up as you described. Before the test, my car had been sitting 2-3 weeks, after which it would normally take even longer to crank before it started up cold. But get this, the car started right away regardless if I used the remote switch or the key switch. It has NEVER started like this since I've owned it (10 years)! Go figure. It seems that it magically fixed itself before the test. If it exhibits the slow cold start symptoms in the future, I'll be sure to pull out the remote start switch and try it again. Thanks,
Dave.

[RarlyL8]

Don't you hate intermitant problems? Sometimes just showing your car a diagnostic tool can scare it straight.

I put the car up on the hoist and snapped some pix. There might be someone in Pelicanland who has never seen one of these contraptions so I'll go ahead and post them.

The remote start switch leads were attached to the starter and the line run into the engine bay where I secured the switch. I figured it was a good idea to have this item armed and ready throughout the testing period. Not much fun being stranded somewhere if you can help it.

[Joe Bob]

The long wait after turning the key....was a bad check valve in the neck of the fuel pump for me.

[jamesd312]

I have a '77 911s US car with all the anti smog stripped off. I bought the car in California and had it shipped to the UK.
Contrary to what the car company had claimed the engine was a complete non runner. A top overhaul followed with new MSD ignition, recon WUR, fuel metering unit, fuel accumulator, fuel pump check valve ie everything was either renewed or reconditioned.
On starting the engine would immediately rev up to about 3000rpm and die. After 3 attempts it would get going on a few cylinders and stutter itself into life which usually took about 30 seconds. We looked at everything including the butterfly setup in the throttle body and discovered that some 'amateur' had been in there before causing damage with a screwdriver. We sorted the butterfly out, reseated it so there was no longer an excess of air on start up and it worked.