1983 sc Cold Start Issue

[cwinters01]

Hello:
I found several cold start threads, but nothing described my same issue, so I was hoping someone out there has experienced my issue and figured out the problem?

A little back story...I live in San Diego, I usually drive my Porsche a couple of times per week to work and back, then occasionally out for a long several hour (harder) drive. Roughly 6 months ago, it started having an intermittent cold start issue. I would drive the car as normal with no issues starting the car during the day. I would park the car for a few days, then go out and try to start it and it wouldn't. It turned over fine, but seemed like it wasn't getting spark. Go out a few days later, and the car would start right up and start fine throughout the day, as needed. A couple of weeks later, the same issue, and the whole cycle repeats itself.
This cycle lasted for a few months. Then a couple of months ago, the issue stopped and I have not had the problem at all now for a couple of months...until this morning. This time, a slight variation of the start problem though. The car started fine, warmed up and was running fine. I started to back it out of the garage and the car stalled. Tried to restart the car, but it wouldn't start. Turns over fine, but again, it is almost like it isn't getting a spark.
As with every other time, I looked around in the engine compartment, but can see no loose connections, nothing unplugged.
Has anyone experienced this one, and any immediate ideas of what is causing this?
Thanks very much,
Christian

[GaryR]

Do you smell gas? Could be a failing CDI box, but if it doesn't smell gassy, next time it doesn't start right away before you crank it to death try popping the air cleaner off and with the ignition key on hold the throttle plate down for 2 seconds. You should hear the injectors squeal pretty good. Hop in and try to start it, if it starts it's a possible CSV system issue, if not keep looking...

[cwinters01]

Thank you for the response Gary. No real gassy smell (beyond the normal) that I have noticed. I'll do as you recommend.
Thanks again,
Christian

[cwinters01]

Update: Got home tonight and the car started right up, warmed up and drove fine. After the first startup, I quickly shut down and checked the throttle plate...could clearly hear the injectors. Also, could clearly smell gas.
Now it appears that it is one of two things:
1)It flooded when it stalled this morning - argument against this is i don't recall it smelling overly gassy this morning, though i was in a hurry to get to work. Another argument against would be the times previous (noted in the first post) where the car wouldn't start to begin with.
2)It is intermittently not getting fuel at start-up for some reason.
I guess I will have to wait until the next early morning "gift" from her to find out.
Christian

[theiceman]

I think you need to really troubleshooting this. You said it "seemed like it didn't have spark"
Verify this.

[cwinters01]

"I think you need to really troubleshooting this. You said it "seemed like it didn't have spark"
Verify this."
Thanks. My initial thought was that it wasn't sparking, I was assuming that I was getting fuel at startup...but it is very possible that that was a bad assumption. As noted, in all of the instances this occurred, I don't recall a gas/gassy smell.
Now that everything is working fine again, I'm somewhat at a loss of how to troubleshoot...I just figured it would have to wait until it happened again...

[michealwhelan]

Had similar issues with my 83 911 SC 3.0. Ran all the checks and pressure tests twice. The intermittent mature made me suspect my CDI was getting flaky. New one was $2200, rebuild was $800, MSD was $350 including new coil, cap, rotor, plugs. I went with the MSD 6 AL-2. It solved the problem. About 6 hours install time including cleaning up wire harness and under hood parts. It started right up. I advanced the timing a bit (still playing with that). For me it was a great option. I am not a purist and my car is a driver, babied, but a driver. Better power, starts instantly and keeps running.

[Bob Kontak]

Originally Posted by cwinters01

Update: Got home tonight and the car started right up, warmed up and drove fine. After the first startup, I quickly shut down and checked the throttle plate...could clearly hear the injectors. Also, could clearly smell gas.

You lifted the air sensor, correct? Throttle plate movement will not kick the fuel pump on.

Anyhoo, the fact your car stalled when pulling out of the garage is odd when related to a fuel issue. Cold start/warm start issues seldom tie in with "My car just died". Once running, a cold start valve not working or residual pressure loss is of no consequence.

Before agreeing with GaryR and MichaelW regarding the CDI box, does the car putt and sputter when you try to re-start it? If it does you may be getting spark.

Try the air sensor test AFTER the car dies.

My Permatune box(es) took 10-15 minutes to cool down before the car would fire. Since the MSD 6AL install in 2003, not one issue.

[GaryR]

So there is no confusion, my procedure is only if the car will not cold start and all it does is inject some fuel into the cylinders (assuming the cold start injector isn't doing it)..

[Roslin]

Do you have the factory key operated alarm system in the car ? I have had similar issues, but after i stopped using the alarm, there has been no issues.

[Bob Kontak]

Originally Posted by GaryR

So there is no confusion, my procedure is only if the car will not cold start and all it does is inject some fuel into the cylinders (assuming the cold start injector isn't doing it)..

I am with you. I was focusing on the fact that the car stalled after warmup pulling out of the garage. My thinking was on the warm start procedure to pump up line pressure, but the more I think about it that is a long shot as the issue is that the car died.

[GaryR]

Originally Posted by cwinters01

The car started fine, warmed up and was running fine. I started to back it out of the garage and the car stalled. Tried to restart the car, but it wouldn't start. Turns over fine, but again, it is almost like it isn't getting a spark.

Sorry Bob, I missed that part, and that would have nothing to do with the Cold start system being energized.

[Bob Kontak]

Originally Posted by GaryR

Sorry Bob, I missed that part, and that would have nothing to do with the Cold start system being energized.

I should have expanded a bit on the "why" for proper context.

Need to do a spark check after one of the unexpected shutdowns. Bummer is two people are needed and there is not a consistent pattern of failure for planning the check.

[Vereeken]

Try to check the coil first much cheaper to replace. Before replacing check this forum for posts on BoSch Silver Bullit.

The intermittent nature can be due to coil issues.

I agree with others that CSV is not the most likely source; I think it works or doesn't.

Tony has must certainly tested 10 of them so he would be able to confirm.

Michel

[michealwhelan]

Originally Posted by Bob Kontak

You lifted the air sensor, correct? Throttle plate movement will not kick the fuel pump on.

Anyhoo, the fact your car stalled when pulling out of the garage is odd when related to a fuel issue. Cold start/warm start issues seldom tie in with "My car just died". Once running, a cold start valve not working or residual pressure loss is of no consequence.

Before agreeing with GaryR and MichaelW regarding the CDI box, does the car putt and sputter when you try to re-start it? If it does you may be getting spark.

Try the air sensor test AFTER the car dies.

My Permatune box(es) took 10-15 minutes to cool down before the car would fire. Since the MSD 6AL install in 2003, not one issue.

I should have clarified. My coil tested good and only replaced as a recommendation of other MSD users and the factory. Timing on my car is now at 12 BDC with the MSD (Factory spec is 5 BDC). This was a trial and error process. Had a lot of backfire between 2000 and 3000 rpm until I pushed it to 12 BDC. Still working on the timing issue.

[cwinters01]

Thank you all for the responses...this place is incredible, and such an amazing asset!
Michael - Thank you very much for the suggestion; I am actually thinking that I may go down the MSD path, so the timing of this post could not have been better. I'm going to research MSD further on Pelican...I've ready about it also in Wayne's book.
Bob and Gary, yes sorry, I lifted the sensor plate. Typically, there is no coughing or sputtering, and I don't recall a fuel smell either. I don't think this was a flooding issue after all. The engine just turns over, but either isn't getting fuel or spark. I replaced the CDI box ~ 12 years/40k miles ago. How long do these things typically last?
Hey Roslin, while I still do have the factory alarm in the mix, it isn't connected...I have an aftermarket installed (since I bought the car in '99)
Michel, I will check the coil (first research the thread you noted "BoSch Silver Bullit")..agree that there is no use throwing $ out the window.
Thank you all,
Christian

[michealwhelan]

The thread 83 911 SC engine quits when warm is the end to end help advice and work I went to in an effort to fix it right. I would suggest eliminating the good a step at a time. There are a lot of tests that you can do to narrow down to the real issue. Before you run out and buy the part make sure something else is not causing the issue. My old CDI was the original so I was not surprised when it turned out to be the issue. The above thread had a lot of great advice to help you troubleshoot the problem. Good luck, and by the way I love my MSD 6AL-2. Did final tuning today and it makes the car act like a Porsche again.

[cwinters01]

Thanks again Michael; going to be an interesting next few weekends!