Starting issues (intermittent)

I am having starting issues with my '02 Cab with tiptronic. I have searched the forum and have no real clear answer. Occasionally, when you turn the key to the start position nothing happens other than all of the dash lights illuminating like normal. You can cycle the key a time or two and it will then fire up. I replaced the battery a few weeks ago, so I know it's not the battery. Also after reading about the ignition switch issues that lead me to believe I had one failing as well. I replaced the switch and all was fine for a couple of days, then it did it again! I have checked battery connections and they look good. Like I said, it is an intermittent problem and may not happen again for several days, but it sure make you nervous to leave town without knowing what the cause of the problem is. Has anyone had this problem and actually found the problem? The only other thing I haven't tried is switching keys to see if the transponder is giving problems. Thanks, Tony

bad ignition switch - common problem, easy fix, cheap part woops - you replaced that so the park sensor on the trans gear selector... I know there is such an animal but didnt have a TIP so cant say where. It is the thing that says you are in P or N so the starter will engage - thats my bet - if not then the starter might have a dead spot in it...

The gear indicator is working fine. As for a dead spot in the starter, it would seem that if you had a dead spot, it would not work again until the armature had turned past the dead spot and there is no way to do that. Tony

it sounds SO much like ignition switch... did it act excactly the same before and after you swapped it out?

Ed, nothing has changed! I have swapped keys and will see if that cures the problem. Other than that, I have no clue! When it does fail to start, the lights in the dash doesn't dim or change at all so there is obviously no real current draw. Thanks, Tony

Hi, I see this thread has died, but I am having the exact same problem as lote. '03 C4S 6-speed 4th owner; ignition switch was repleaced recently by prior owner. A. Battery fully charged, key in, clutch to floor, parking brake on, gear shift in N; B. Key to Position 1 all dash lights, battery topped off, oil level timer times out, whirring and other noises of solenoids and electric motors (not sure if this thing has a brake fluid pump like my 964?); C. Key to position 2, no starter - nothing - silence. This may happen once or a many (so far 6 or 8) times before car will crank and start right up. Car is new to me, and prior owner said to wait for the oil level thing to finish before cranking it. Now for the questions: 1. Can the oil level timer be eliminated by the dealer - thought I read that somewhere? It is a nuisance. (Yes for the blonde in Hollywood, probably a good thing.) 2. Nobody has offered any other solutions besides the ignition switch. It looks from the records, like owner 2 had the "engine bay wiring cleaned and checked", can this be a clue? 3. How robust are the 996 starters? Can it be a solenoid going bad? 4. What about the key - is this really an issue? 5. What other gremlins might I check? TIA, DC4

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Assume yours is a stick shift. Have you checked the clutch switch?

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+1.... check this first.

Thanks, at least one question out of 5 answered... ;o) I'll check that tonight. I had a similar problem with a cruise control switch in my 964. DC4

Loose ground strap???

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AFAIK the oil level timer has nothing to do with the engine's starting operation. You can choose to wait for the oil level timer or not. If it is just 5 seconds I wait cause I like to check the oil level frequently. If I'm making a series of short trips and I checked the oil level at the beginning for the intermediate trips I skip the oil level test or if the timer requires more than 5 seconds I just turn the key to start the engine. Never had any problems. Engine bay cleaning always raises the spectre of water getting into where it should not get into. Water can get into a sensor connector and cause electrical problems. One possibility is a critical sensor -- crankshaft position sensor or camshaft position sensors -- deliver an implausible signal and the engine controller can refuse to allow the engine to crank. Starters and starter solenoids are like any other device. The can fail at any time, but the symptom does not point to a starter or solenoid. The key can be an issue if the RFID pill inside is not activated by an RF signal from the transmitter in the dash. The RFID pill receives an RF transmission which provides it with the energy to respond with its ID. The in-dash receiver accepts this and confirms the ID is valid and if so then permits the engine to crank. My guess is the problem is with the clutch interlock switch. If the switch is original you should consider replacing it. The switch is not expensive nor hard to replace. At the same time check to be sure that when the clutch pedal is fully depressed the clutch switch is completely depressed. In some cases even if the switch is ok the mechanical aspects of the clutch pedal linkage and the switch conspire to cause the clutch switch to be not completely closed and in this case the engine will not crank. One possible way to id this is occuring is next time the symptom appears, turn the key to the off position and release teh clutch pedal completely, then with some force shove the pedal to the floor as far as it can go. Not need to bend/break anything but do make an effort to ensue the pedal is fully depressed. If the engine starts then the switch is most likely not being depressed completely. Look at the switch and with an assistant see how you can adjust (bend) the clutch switch bracket or finger or whatever to ensure the clutch switch is fully depressed when the pedal is depressed. Sincerely, Macster.

I changed to my other keyfob and it seemed to be ok for a while. It still does it, but not nearly as often. Mine is a tip so I have no clutch switch. The problem with an intermittent problem like this is that the dealer can't fix something unless it is doing it at the time they have it. It may do it once in a week or not at all for a month or so! Tony

To you have other chipped key on that key ring? If so try take them off for a little while and see if that fixes the problem.

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If the car is a Tip and no start symptoms: dash lights on, just no crank; remain the same from key to key then I'd suspect the Tip park position sensor or its connection. It might be worth the effort to find this sensor and its connector to the harness and disconnect the connector then reconnect it. This action removes any surface corrosion that can build up over time and produce a much better electrical connection. I've never owned a Porsche Tip but does not only the Tip gear selector have to be in Park but doesn't one have to depress the brake pedal while starting the car? If not, then nevermind. But if yes then this means there's some kind of interlock switch and it or its connection becomes suspect as well. If this switch exists my suggestion for the Park sensor switch/connector "trick" above applies. Another possibility, harder to trouble-shoot, is a critical engine sensor is delivering an implausible signal and the engine controller refuses to allow the engine to crank. The sensor heals itself from the power cycle that occurs when the key is turned off then turned back to the on then start position. There may be an error code logged if this happens and the tech has the PST2 hooked up to read it then, cause the error code might be very transitory going away upon the next engine start. Or there may be no error code because the error does not effect emissions. Like I said a harder possibility to trouble-shoot. Sincerely, Macster.

FOUND THE PROBLEM. There is some great feedback - thanks especially to Macster for the detailed response. The problem was exactly what he described - I really have to push the clutch sort of hard into the floorboard - then it starts every time. Thank goodness nothing more than the switch. Next step will be to adjust or bend or whatever, so the switch is activated "easier". On the oil level before start - again spot on. I can start the car without waiting, or simply cancel with the computer lever. Thanks, DC4

If the switch is like most on pedals it will be a screw in. Try adjusting how far it is screwed in with the lock nut if it is the common variety.

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Great to hear your starting problem is solved.

Wasn't a screw adjustment, rather just bent the "blade" out a bit. No problems since! DC4

DaveCarrera4; you still around? Did this result in a permanent fix? I'm having the same issue. I'll take a look at the sensor to see how to bend it. Anyone else?

A question to Macster. Are these the switches that are the same exactly, One operated by the brake pedal and the other by the clutch pedal? Doesn't either when depressing take out the cruise control if engaged when driving? If so, could they be interchaged to make a test on the starting problem?

The pedal fully released switches are the same for brake and clutch. #17 in the diagram below (click link). http://www.autoatlanta.com/porsche-p...-05/702-00.php The pedal fully depressed are different for brake and clutch. #16 for the clutch. The pedal pushes the metal tab in, closes the circuit, and allows the engine to start. Some people tie wrap this switch allowing clutchless starting. However DO be careful, the transmission MUST always be in neutral if you do this hack. Even one mistake can cause damage. To eliminate #16 switch you can unplug the two wire connector from it, and jumper the leads (put a wire in between the two contacts). If the car starts every time then that is your problem.

I have the same problem with my 2002 C4S stick shift. I changed the clutch switch and the ignition lock switch. Still not cranking all the time. In addition I now have a airbag warning light that stays on and a red blinking light from the radio when the car is running. Any other suggestions?

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I installed a new starter and battery. Still won't start. Only get a clicking noise from the rear. Airbag light still comes on. What else could there be wrong?

The clicking noise is the starter solenoid kicking in...the problem is you're not getting enough voltage/amps to turn over the starter. Clean all connections including the ground straps, substitute a different battery, try to jump it with the connectors in the engine bay. If that works, you've got a loose 12V connector to the starter somewhere.

Thank you. Does this mean the ignition switch must be ok if I can hear the solenoid kicking in? The battery is brand new.

Yes...if the solenoid is clicking the ignition switch is more than likely not at fault. Two circuits go to the starter, think of it this way - you turn the ignition switch, it activates the solenoid, the solenoid acts like a great big switch that throws the main 12V amperage at the starter which then engages and turns over the engine. The little tiny wires from the ignition switch work the solenoid switch on the starter. The great big wires (like battery cable size) are what work the starter.

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11.90 V at the starter from the battery. Jumping it with my truck did not do it. It turns over when I bridge the two big connectors but it did not when I connected a jumper cable to the terminal coming from the battery (left connector).

I did not bridge the two big terminals. The starter turns over when I put power on the smaller terminal.

I checked the '99 circuit diagram and there is a relay called "Start Lock relay" which is between the ignition switch and the starter solenoid. Energized by the ECU. Wonder if your car '02 has it also and maybe the relay is faulty or connection to the solenoid is bad. Part number is 996.615.110.00 http://forums.pelicanparts.com/porsc...lay-996-a.html

Thank you. I will check this next

After reading here more, I tried to start it down the street. Did not work. Didn't even try. Like there is no spark. Could this be the immobilizer?

It was (again) the ignition switch. Just three Month ago I replaced it and now again. But it runs now again and the airbag warning light is gone too.

Just to follow up, I applied the zip tie solution for a couple months and, for me, that isolated my problem as the clutch switch. The car started 100% with the zip tie in place. I recently cut off the zip tie and very barely bent the arm on the switch. So far so good, but I've only started the car maybe a dozen times since I bent it. I've had my car at a shop for an ECU read and then a paint shop for a minor touch up. Even though I warned them, I was so worried they would start the car without depressing the clutch... So I had to take off the zip tie.