JPP

^^^ Loren, I forgot to mention .. I swapped out the #61 starter relay (53) with the horn relay (53, same part) because I knew it was working ...


Anybody know the part number for the clutch Microswitch? I'll be trying to figure it out today with Sunset Porsche .. they couldn't find it yesterday in their PET system either so I sent them a picture .... can't see it clearly without removing the part. Thanks ....

TMc993

EDIT: Corrected in aother post

JPP

Well, it's confusing on the PET because that is item #18, shown as qty 1 only and that is shown as the cruise control switch. When I look at the physical parts on the car, the wiring to the cruise control switch is two blade connectors and the wiring to the clutch microswitch is soldered on to the switch and goes to a connector on the floor. Did you read that number off a clutch microswitch part?
thanks,
JP

NC TRACKRAT

Why replace a part that can potentially give you the same problem again and is not really needed? Just leave the microswitch by-passed. Mine gave the same aggrevating problem until I took it out of the equation. Now, I just put the car in neutral and it starts every time.

JPP

Well, I would, but let me ask you a question ... when I push the switch bar with my finger, I hear a slight 'click' internally inside the swith as it engages .. it happens about half-way through the bar's total possible travel .. IF the switch is defective internally, couldn't it possibly fail even when the switch bar is physically pushed closed?

Allen

Yes...sometimes the actual contacts of a switch can become "dirty" and fail to allow proper current flow. So even though the contacts are making physical contact...they may not be making proper electrical contact. You can check this issue by: (1) removing the switch and examining the contacts...are they clean or do they appear "burnt/corroded/dirty"? if yes, you can use fine sand paper to carefully clean/scrub the contacts. (2) using multi-meter to check resistance of the contacts. With the meter on both sides of the switch...move/jiggle the switch actuator and see if the resistance moves from MAX (should be with open switch) to some value. Then do the inverse...close the switch...meter should read MIN (should be 0 for closed switch) and see if the resistance jumps. Bottom line....closed switch should have steady 0 resistance, open switch should have steady MAX resistance.

JPP

Ok .. so you're saying, if the exterior switch bar is clean and where it contacts is clean, when it's in contact at full throw, the internal's don't matter .. closed is closed. Is that right?

Lorenfb

"Yes...sometimes the actual contacts of a switch can become "dirty" and fail to allow proper current flow."

Right, the clicking sound of the switch is not necessarily an indication that
the switch's electrical connection is O.K. Bypass the switch for a number
of days to fully conclude that it's the problem, since the problem is intermittent.

Paul902

Agreed, that is confusing...My car is a '96 and does not physically have the starter microswith (the one you marked "This one"). It does have cruise control, and does have the switch you marked "Not this one." It starts without depressing the clutch pedal. So, the PET seems incomplete in that it does not show the starter microswitch. Can you remove the starter microswitch and get a part number off it, if needed. Other than the wiring to it, does it look physically the same as the cuise control microswitch, as that part number is listed (#18), and you could order that if you need a new switch.

As noted above, the phyical contact does not mean electrical connectivity. With an Ohmmeter, measure resistance. You should see 0.0 to 0.2 Ohms when the switch is closed, and the meter will likely display Mega Ohms when it is open (whatever the meter maximum is). If you can open the switch and inspect the contact, ensure that there is no oxidization on them, which prevents electrical connectivity, and would give you a high resistance measurement. Your automotive or electronics store will have electrical contact cleaner, which will remove any surface film of oxidization that may be present.

Paul902

Another thought, Jon Paul, check the condition of the soldering on the switch. You may want to reflow it if you can disasseble it to ensure good solder connection. Perhaps a faulty solder joint, similar to what causes the DME relays to often fail, is at play here. That can be intermittant. Also, check the condition of the wiring at the floor connector and clean it with contact cleaner.

JPP

Agreed. So far, the car has NOT failed to start since I applied the tie-wrap to the switch and closed it. I took it on my Sunday errands run today (something I would NEVER do in this car normally ... ) stopped and parked several places, sometimes letting the car set itself, sometimes pushing the remote and locking the car ... so far, the car has started every time. HOWEVER .. I will continue to do this through next week to see if she's just 'foolin' with me ... she's the devil. I'll keep you posted.

Yes, exactly .. the PET is incomplete. IF it were using the same switch as #18, it should show qty of 2 ... which it doesn't. Also, if you noticed, it went through a part number roll for '97 and on ... so there's THAT to deal with as well.
Sometimes Sunset will have an internal note on their dealer PET system showing factory changes/addendum's that list parts not shown on the regular PET system .. hopefully that's the case here. If they can't figure it out, then I'll pull the switch in a few days and have a look at it to see if I can pull a part number off of it. As I noted above to Loren, so far, the car hasn't failed to start since I by-passed the switch yesterday. I'm pessimistically cautious at this point and will continue to drive the car around next week to see if the gremlins are dead or just hiding ...

BTW ... Thanks ALL for the comments and input, it's all leading me to the resolution. This is the way it gets done when you're an electrical moran like me

Paul902

JPP, electrically speaking, you have NOT by-passed the switch, you have just closed it by another means than the clutch pedal. If you continue to have good success with it, it suggests that the clutch pedal action was not properly closing the switch, and perhaps an adjustment of the external arm, or switch position is needed.

Edit: JPP, the clutch pedal has a rubber stop on the backside of the floorboard. It is the nub I was asking you about in my PM. It is an adjustable stop for how for the clutch pedal travel is. Could it be that your's is adjusted such that you are getting proper clutch operation, but the pedal is not travelling down far enough to close the microswitch every time?

JPP

I checked the travel yesterday when the car was starting ... and it would start even if the clutch was depressed only half way .... I verified that when I was messing with the metal contact arm and can hear the 'click' at about half depressed position. When I pressed on the clutch with my hand, it looked like the switch contact arm was closing all the way but VERY difficult to really tell .. but it all made me think that there was the arm .. and maybe it had a contact on the outside when it was closed .. and there was the 'internal' switch contacts that are supposed to close the circuit way before the physical arm has been depressed all the way. I won't be able to verify the physical aspects of the part until I remove it .... unless somebody here reads this and happens to have a switch lying around they can post pictures of ... hope springs eternal :-)

lcorkum

Jon Paul,

Here is my message back to paul when he asked me about your problem since I too had a problem starting my car which is a 96 C2. I will just copy the message again here and maybe add some more.

I know you replaced the cable for the Ground to the batter but did you check carefully the connection to the body to make sure you had a very good contact?

I would buy a spare Ignition Switch so you can test yours without installing it like my message below and then have it as a spare that you carry with you along with a spare DME Relay, I also have a spare Start Relay now but you can always use the Horn Relay to get home if stuck.

Keep us posted on any difinitive results, these problems are going to get more common as our cars get older and gremlins like these are difficult to track down but always start with the simple stuff and elliminate any chance they are the problem first.

Cheers
Lloyd
++++++++++++++++++++++++++++

Paul

I was sure mine was the Ignition Switch also however it was not and it is not where you should start to look since it is the hardest to replace. The Start Relay is number one on the list to replace after checking all the fuses!!!, I am attaching a few Pictures of the Start Relay & Horn Relay that can be interchanged to see if the car will start. Next make sure the plug is fully engaged on the back of the switch, see pics. if this fails I would have the DME Checked before attempting to replace the Ignition Switch however if you can get your hands on a known workinging Ignition Switch you can pull the plug off the back then plug into the one you have in your hand then using a philips screwdriver turn the Ignition Switch in the On Position making sure to release if the car starts, it is a momentary engagementfor the start position same as using the key. If all this fails there would have to be an issue with the Harness but that would be my last resort since it is a big replacement job if you had to do it and you would know if there was any reason to suspect it by a possible intermittent operation of the car when it was working.
My problem was the relay and l looked at all the difficult things first which really isn't normally how things fail, it is usually the simple things that go wrong first.
Good Luck with your investigation.
Lloyd

lcorkum

Jon Paul,

Here are my Pics I spoke about in my message. By the sounds of all the checks you have made so far I would get a Switch and try that next.

All the best
Lloyd