SC Starts for Mechanic But Won't Start For Me

[Mattlock18]

Took the SC out last week for a meeting with a client. When I went to leave his office it kept cranking but wouldn't start. I left it a few hours, went back and still nothing. So I had it towed over to the local Porsche dealer. It's been a few days and I called to see the prognosis. He says it keeps starting right up for him. Anyone have any suggestions. I had never had any problems with it before last week, but don't want to take it home from the shop only to have to get it towed back there when it doesn't start again. Any help is appreciated.

thanks

[Peter Zimmermann]

If your "no start" was an attempted hot re-start, I would suspect that your fuel accumulator is bad. Is your mechanic trying to duplicate the temp of your no-start condition? If he's doing cold starts only, the car will start every time with a bad accumulator. I can't explain the "left it a few hours..." part of your no-start problem, perhaps there is also a problem with your fuel pump relay.

[Bob Kontak]

Do you have a Permatune box? Symptoms sound the same as a bad box except for the few hour rest time before not starting again. Usually no start period is less than one hour.

[stealthn]

Sounds like a bad ground to me, check the strap at the tranny underneath. I also had similar problem with a failing starter, was hit and miss when it would work. If I banged it the car would start. I replaced it everything's been fine since.

Good luck

[ToddM]

You will also cold start every time and not hot start with a bad starter solenoid (a very common SC failure)

You didn't mention if the engine would turn over or not when you tried to start it.

[crustychief]

Get a lawyer.

I would also say fuel accumulator, all that cranking and no starting unless cold.

[Vincent Hill]

Looks like all great advice here! Get the Largest Fuel Accumulator that will fit and Install it! Also stay away from Shell gasoline! Even in cold weather the make up of the fuel will allow it to vaporize and stop your engine from running.

[mikesride]

Strange... out of all the fuels Ive tried shell has been the best....Same prob with my 82 sc and a new fuel acc. solved it very simple and as far as Porsche parts go, very reasonable price right here on Pelican! Good luck!

[dtw]

Originally Posted by crustychief

Get a lawyer.

....wha...?!?!

[JJ 911SC]

Originally Posted by mikesride

Strange... out of all the fuels Ive tried shell has been the best....

V Power with nitrogen + the 91 (in Canada) does not have any Ethanol Crapola

[crustychief]

Originally Posted by dtw

....wha...?!?!

His SC has to be cheating on him. Sorry, OT.

[Mattlock18]

Thanks for all the advice. I talked to the mechanic this morning and he said everything is fine. I asked him if he tried starting it under hot-start conditions with the engine warmed up to running temperature and he said "no". I told him to try that and then let me know the results. Apparently that will take another day. I'll mention the fuel accumulator when I talk to him again.

I thought it would be a quicker fix to have the dealer work on this while my regular mechanic is on vacation this week. I'm sure by the time I get the car back my regular wrench will be back from his vacation and I could have saved myself the headache of going to the dealer.

[JJ 911SC]

Originally Posted by Mattlock18

... he said "no". I told him to try that and then let me know the results. Apparently that will take another day...

He is going for a nice ride...

[dshepp806]

Careful they don't just crank her up and let her sit at idle until she reaches temp....not good.

Doyle

[Mattlock18]

Well I told the wrench to drive it around and then check and see if it starts. He did (or says he did) and I picked it up last night (running) and drove it home. Hop in it today and it won't start. Just like last time I just get the cranking but no turn-over. The only difference is that this time it was sitting in the garage overnight and I hadn't just driven it. Don't know if this changes any of the advice above or gives any more insight.

thanks for the help.

[JJ 911SC]

Matt

Ask the mechanic if he has done anything?

It's an 83, is it still fitted with an 3 liter?

[Peter Zimmermann]

Originally Posted by Mattlock18

Well I told the wrench to drive it around and then check and see if it starts. He did (or says he did) and I picked it up last night (running) and drove it home. Hop in it today and it won't start. Just like last time I just get the cranking but no turn-over. The only difference is that this time it was sitting in the garage overnight and I hadn't just driven it. Don't know if this changes any of the advice above or gives any more insight.

thanks for the help.

Actually, it changes everything. Try this. Lie down next to the front wheel/tire, so that you can reach under the car behind the gas tank. You will see a rectangular "skid plate" that's roughly 1' x 2.5', and is fairly heavy metal (it's fastened in four places). Take a mallet and tap against that plate, at about its center (side to side), a couple of inches back from the tank. This can wake up a sleeping fuel pump. After doing this, if the car starts its highly likely that the fuel pump is failing.

Also, in the front trunk, locate the fuse box and examine the fuel pump fuse (#6 from the windshield end of the fuse box). The fuse might be corroded enough to prevent voltage from passing through it, and it must be 25 amp (blue in color) capacity.

There is also a relay (above the fuse location, red in color, and about 1" in diameter and about 1" thick). Grip that relay and pull it straight out and look at the five pins. If any look burned, simply use one of the black relays (horn, etc.) that you know is OK, plug it in and see if the car starts.

Good luck!

[JJ 911SC]

Originally Posted by Peter Zimmermann

Actually, it changes everything...!

Peter

You probably got it nail. Nothing worse then chasing changing symptoms as you go along.

Actually my next question for Matt was to tell us how he start the car. May sound "funny" but I'm use to first hear the motor blower (long story... anti theft device) and listen to the fuel pump.

I remembers in my Navy days when we used to ask the operators what was the last thing they did before the equipment smoke up, after we slap them a few time... we knew where to look, the good old days

[Bob Kontak]

I was typing while Peter Z was posting but I will post the whole thing anyway. Good luck and give us feedback.

Did you pay the mechanic for any work?

From what you have told us he just got in the car and started it occasionally and took it for a ride then started it after it was warm per your instructions. That sounds like $60 dollars worth of work max. Was it a Porsche dealer?

You car not firing this morning changes almost everything. We do now know that the starter cranks the engine and that it does not start cold for YOU at least. That lessens the probability it is the fuel accumulator. If the car drives ok when it is running the gas issue is gone. I mentioned the Permatune box and received no response so I am guessing you don't have one.

That leaves the fuel pump relay and all the other possibilities not mentioned.

So follow these instructions and have some data ready for your real mechanic:

1. Remove and replace your fuel pump relay. Slide it in and out a few times (that's what she said) to knock off some corrosion. It's in the front trunk in the fuse panel - round red one - closest to the windshield.

2. Set your parking brake and reach in and turn the key to "on" so the instrument lights come on but do not start it. Walk back to the engine and pull the air cleaner off and reach in and lift up the air sensor with your fingers. You should hear a nasty-ass skreeching noise that indicates the fuel pump is delivering fuel to the system under a good deal of pressure. Only a second or two is needed. Not sure what causes the noise but you will know it if you hear it. If you don't hear it that relay is probably the issue.

So now you got fuel if you hear the noise. This is good. Try to start it. Just once or twice and then perform the next step if it does not start.

I have a hunch and I think you problem is a simple electrical issue. Try starting after each of the next steps.

3. Turn key off. Remove the wire connection to your CD box and re-fasten - do this a few times without reefing sideways on it. Again - dusting off some corrosion.

4. Look at the wires on your coil. Wiggle the connections to make sure they are tight.

5. Remove and re-install the fat (secondary ignition) wire between the coil and distributor.

6. Look at the green wire that is connected to your distributor and leads into the CD box wiring connection. Rubbing on anything that could create a short?

Finally:

7. Check for spark by having someone start the car while you look at a plug wire placed close to a ground.

Those are the basics I can think of without going into deep diagnosis with a multi-meter.

[Zeke]

Bob K. , that's a nice write up.