Or the immobilizer *NM*

I'm having a starting issue with my 04 GT3. I think it has the same ignition switch as my 02 Boxster S and I am wondering if this ignition switch can be the cause of the problem. First I can tell you that the battery is 18 months old and always on a Porsche maintainer. The car only has about 9,000 miles on it. When I turn the key to the start position I get nothing or just one click like a bad solenoid or dead spot spot in the starter. If I keep trying, so far it eventually starts. When I immediately turn it off and try to restart again it usually does but sometimes not. Could this be caused by the ignition switch or the switch on the clutch ? What would be the procedure for process of elimination to determine the wether it is the starter, starter solenoid, clutch switch, or ignition switch ? Also would a bad ground display this kind of issue ?

That is not the classic failure pattern of the switch. You *could* have a high impedance switch, biut even then i would guess the switch actually controls a relay. So it would either be dead or full. Guess.

As to the brake lock-out - same deal. That's a safety - either on or off.

I'm actually thinking starter brushes - the fact that its better once you move it (to another position, to remove debris?) supports that guess.

As to the switch - its an Audi part/. I've never had a [problem on my 986s, but I've had several failures on several Audis, and helped many others.

The most common failure is "car runs but accessories don't" - you have to manually move it back to accessory position, a PITA, but serviceable.

Another two times i had it prevent the car from starting, although it cranked just fine. Something in the ECU interlock.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

Grant

gee-lenahan-at-gee-mail-dot-com

My read on the description was that there are electrical components that are clicking, not the starter motor.

Wayne, can you clarify? When it does eventually start, is it cranking normally or slowly?

is not very old, and is maintained the battery can still fail. I had a new last but 7 months one time and the car was used regularly.

Another possibility is some kind of marginal connection between the battery and the car's electrical system. This can be at the battery, or where the cables attach to wherever they attach too. I've been told a particularly bad spot is where the negative lead connects. The tech said all that is necessary is to loosen the fastener then tighten it again.

The behavior you report doesn't really agree with a bad clutch switch or even a bad ignition switch or an immobilizer problem.

and, of course, batteries are just plain weird.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

1. measured the no load battery voltage
2. measured the voltage under cranking, or trying (loaded voltage). This can be as easy as a voltmeter int he cockpit if you happen to have one in GT3
3. checked the battery connections - loosen, move to scrub, tighten
4. checked the ground strap

Do you knwo the battery maintainer is working properly?

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

... battery, as has been recommended.
Happy Porscheing,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

Thank you for all the replies. To answer boxsterra's questions it does turn over and starts normally or it just just does nothing or one click sound and nothing. From my experience it does act like a dead or low battery but I ruled that out because of the age of the battery and it is always on the maintainer when not in use, plus the fact that it turns over and starts as normal when it does work. I might add that the car sat for about 8 months without driving except I had to start it and move it a couple times during our home construction project. It wasn't until I went to move it to the new location that this started to happen. Most of you are thinking battery or bad ground so I do have a device to check voltage and load test the battery. I will first check the ground connection at the battery. Are there other grounds that are part of the starting system? Perhaps something at the starter itself? It may be a few weeks before and can reply again as we are in the midst of moving ( as in not having a good time ). I will try and get a helper to check the starter at cranking as Grant has suggested. Do these cars push start when popping the clutch?

the chassis and the block are typically ground, connected, as is the battery ground, by large braids or heavy cables.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

but given this one's history, you might be right!

Grant

gee-lenahan-at-gee-mail-dot-com



Edited 1 time(s). Last edit at 10/14/2014 07:35PM by grant. (view changes)

especially in the winter when i put it to sleep, then run it 80 miles in a day to get good and hot.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

from you I think you better get the car to a qualified shop. I hope I'm wrong but I think the car has suffered rodent damage. If the shop turns up *no* sign of rodent infestation then it can check the battery and if the battery proves to be ok -- I suspect it will be found to be bad -- then it can find the cause of the behavior.

Marc,

I don't plan on using the car until I get whatever is wrong fixed. I was just curious if they can be push started in an emergency like manual transmission cars could years ago.

It ain't like the old days.

The problem is these cars need a healthy electrical system. The car's electrics/electronics has to do more than just crank the engine and supply sufficient power to generate a spark from the coil.

The DME has to be running and with a healthy voltage too. It triggers the spark and the fuel injector pulse. To do this right (enough) it needs its population of sensors working too. The fuel pump has to be running to supply fuel and at the right pressure or you can push the car until you are blue in the face.

Even before the engine is allowed to run, if it will run, the security system has to be able to query the key module for the RFID.

While there have been cases where the engine started when the car was push started, I'd just not bother. Better would be to address what is wrong or get the car somewhere and have what is wrong addressed.

Grant

gee-lenahan-at-gee-mail-dot-com

reason other than to satisfy one's curiosity?

And if it doesn't start one's likely wore out and the car's in probably a less suitable location than it was to begin with.

Some years ago I had a Pontiac van that would have an intermittent starting problem. It turned out to be an intermittent internal connection in the battery. Sadly, the only way to rule out the battery is to replace it with a new one.

See if you can swap in a battery even a used but know good and/or even one of a slightly different size and see if the problem goes away. Swap the current battery back in and see.

Then you can look at the really expensive things.

I tracked down my problem with a voltmeter directly across the battery terminals when it was misbehaving.

If you swap in a new battery and the problem seems to go away, it could be:

- The connection to the battery is faulty/corroded
- The battery is sulfated (much cheaper to fix than replace)
- The charging isn't working very well

So, swapping the battery may mislead you into spending money unnecessarily and maybe not even solving the problem.

This is one of the reasons why I often recommend desulfation as an early step. The symptoms of a bad battery and a sulfated battery are quite similar. But the latter is way more likely, and is fixable.

Boxsterra, will you explain a "sulfated" battery. What are its symptoms, what causes it and how do you "fix" it?

Sulfation is a buildup of sulfate crystals on the battery plates. It happens at any time that a lead-acid battery is not completely charged. It inhibits the battery's ability to receive and hold a charge. It is one of the most common causes of a young (6 or fewer years) battery dying.

The fix is to use a desulfating battery charger. It works by using a series of high-current pulses into the battery. The combination of the heat and agitation causes the crystals to detach from the plates. The longer you let a sulfated battery sit, the harder it is to reverse.

If your battery is more than a couple years old and/or you have left your car sitting for 1-2 weeks more than once, your battery would likely benefit from desulfation.

--

The one I have is the CTek 7002. If anyone in the NYC area wants to use it, I'd be happy to loan it out.

This weekend I had a chance to check battery condition. Voltage showing 12.7. Load test in OK zone and battery recoverd to 12.7 after load test. I backed off the nut on the battery to chassis ground and wiggled it several times and tightened it back up. There are no signs of corrosion at the battery and it's ground. Looks to me like the battery and ground are good. I will next test the starter which calls for testing at operating temp cranking in no start mode. Is there a fuse I can pull that will disable the engine from starting when cranking?

Thanks. I will report my findings. Current temps in my garage are about 55 degrees. Do you think it is really necessary to have the engine at operarating temp to do the cranking test? I am also going to try it on the Boxster to have something to compare to. Both have the same battery in them and they both had the same results on the voltage and load test.

Could the clutch pedal switch cause the same symptoms?

but no starter action that is not based on my experience how a bad clutch interlock switch affects starting.

In the case of my Boxster the dash lights were normal, everything was normal, but when I turned the key from on to start there was no reaction from anything.

Anyone with a manual transmission equipped car can experience this: Just the next time you attempt to start the engine do not depress the clutch pedal. Just in case the clutch pedal interlock switch has been bypassed or possibly failed be sure the transmission in neutral.

The clutch switch is not expensive but a bit awkward to swap out so if you want to eliminate this switch just replace it.

The times -- the thankfully few times -- the dash lights acted normally but the engine failed to crank or start, with sometimes a click, proved to be battery related, just a nearly dead battery.

If the clutch interlock is engaged, it will prevent the signal from going to the starter at all. So here will be no relay click, no solenoid engagement, no starter engagement and certainly no starting of the motor. Or that's my string supposition.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

So if I'm getting this right besides the battery the starting system consists of the ignition switch, the interlock switch, a starter relay, the starter solenoid, and the starter itself. Where is the starter relay located and how can I determine if it is bad? Is the solenoid connected to the starter or elsewhere?

Quote
Wayne K
So if I'm getting this right besides the battery the starting system consists of the ignition switch, the interlock switch, a starter relay, the starter solenoid, and the starter itself. Where is the starter relay located and how can I determine if it is bad? Is the solenoid connected to the starter or elsewhere?

activated.

However, if the security module was involved in this no start scenario you would not get a click or any noise.

My references do not give the relay locations for the GT3, just the 996 Turbo and 996 GT2. The car's owner manual should give these. Or you should be able to get a print out of this from your local dealer.

To test a relay, I don't know off hand, but here's a link that may be of some value:

[www.agcoauto.com]

The solenoid is part of the starter. When energized the solenoid causes the pinion gear to move into engagement with the ring gear (on the flywheel). As soon as the pinion gear is fully engaged an electrical switch is closed which then provides power to the starter. If there is sufficient battery power the starter turns and generally the engine starts and runs.

I'm not sure how this is done but the circuit I believe is designed so the solenoid either fully engages the pinion gear with the ring gear or it does not. This eliminates the risk of the pinion gear being only partially engaged and stripping the pinion gear or ring gear teeth.

The click suggests the solenoid is not receiving sufficient electrical energy. However, the click could come from the starter relay when it is being activated but the relay does not have sufficient 12V power to work. (Maybe the relay is how the starter pinion gear/ring gear teeth are protected against partial/insufficient engagement?)

The behavior really points to a weak battery. However, the power/ground cables and connections at the starter/solenoid also come under suspicion.

..is the device that pushes the starter's gear out and into mesh with the teeth on the flywheel. It is only connected while you crank and then retracts.

When you turn the key, first the solenoid pushes the gear out, then the starter motor is engaged, turning the gear, and when you turn the key back, it retracts and the motor keeps ruining. Maybe :-)

The dreaded "click" one hears is the solenoid moving, but not enough amperage to turn the starter motor against the resistance of the internal combustion motor.

Often you hear "click, groan".

The relay is there because one would nto want to run a very heavy wire a long way, into the passenger compartment, up the stalk, into a teeny-tiny switch, through a teeny-tiny contact and back to the motor. You have a small wire that energies the relay, which then closes and sends power to the starter. relay is simply a switch that is thrown by electricity, rather than your thumb. Some are mechanical, others solid-state.

If you are getting power to the starter *at all* i would guess the switch, relay are ok. Wiring and ground, who knows?

For battery you need to load test. Does it fall below 10+V under full crank? This determines output impedance of the battery. it can have no -load voltage but not the capability to maintain voltage when loaded.

The rodent thing is a real worry.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

Had some time to look at this on the weekend. Battery voltage before cranking with fuse removed to disable from starting was 12.6. Cranking voltage dropped to 10.8. When stopped cranking battery voltage came back up to 12,5 in about 4 seconds. Repeated this 6 times with same results. I then bumped the starter to try and find a dead stop. Could not find one. I'm thinking from sitting a long time without starting there may have been some corrosion in the solenoid or starter. If the problem returns I will report.

Grant

gee-lenahan-at-gee-mail-dot-com