Cupcar#12

that is what my curren thinking is actually - can the replacement be rekeyed to fit the stock existing key?

tall02

The Porsche ignition switch is attached on the back of the key mechanism. Thus you keep and use the same key and tumblers. It is tight under the dash but what helped me was I also took out the left vent on the dash. There is one screw on the side of the dash which you can see when you open the door. I also unscrewed and drop one metal eleca box to allow room to unscrew two phillips screws which hold the ignition switch to the back of the mechanical key switch. I left the mechanical key switch mounted in the dash.

Bingo ...... no problemos with the hesitation.

Good luck

Tall02

sturm

Any resolution or updates?

I have the same problem....intermittently

white rsa

Cupcar#12

sorry been on vacation & i just recieved the ignition switch in the mail last night hopefully i am going to install in hte next 2 days and give it a whirl.
i will remove the lower dash and the vent to gain access.
if this does not work the next thing to replace is the the Central electics panel itself (fairly cheap at $130ish)

540964

have you replaced the coils yet? solved my problems about 3 years ago.

MassGuy

I have th esame problem and I know it is the AFM. I would recheck this area. I know what you are talking about.

Everytime I reconnect the AFM the car will run fine until a good jolt.

I am convinced........

Cupcar#12

Ignition switch done - its a PITA to get to the top screw on the module.... not fun at all.
luckly the screws came out fine though. i will see if i can repeat the problem tomorrow, if so on to the electrical panel then the coils, and just for triple redunancy i'll get a new DME relay.

tall02

Dear Cupcar #12

After replacing my ignition switch I did hear one brief interuption within 30 days so I pulled off the AFM (Air Flow Meter) behind the air filter box and opened the top plastic cover. This is held in place by a silicon sealant. Inside is the air flapper is connect by shaft to the delicate brass wiper. The wiper has three contacts which ride on a carbon ribbon resister. I had deep grooves and I read that if the wipper does not make contact then the computer believes the air flow has stopped and the air flow door has closed. Sending this signal back to the computer cause the system to shut down until the circuit is reconnected by vibration as you are coasting. I lightly sanded the ribbon resistor with 1600 grit paper and sanded the underside of the brass wiper. Reassembled with silicon sealant and no problems since.

Just another no-cost option for you to check. But be very gentle and do not bend anything, move the alignment or sand too much

Good luck

Smokin

Hmmm... I was about to post about a similar problem but thought I would try one more search... Then I found this thread with a keyword variant.

I am having the same issue(s)... The first few times it cut out there were no bumps involved... I replaced the DME relay with the newer model and thought I had beat it. Now I get the cut-outs after going over just about any bump that makes a rattle. So... It could be just about anything, eh? I guess I have a few places to start looking... I have a Hall Sensor code that I can't figure out. Perhaps it is related. My wife really wanted to go for a long drive tomorrow but I'm not sure I trust it and don't want to get stuck on the side of the road. The drive is supposed to be for relaxation... Not the stressful breakdown and the inevitable screaming in my ear that follows. I was hoping for a quick fix... Looks like I'll have to spend another day in the garage going over it again. I don't think it is the 02 sensor since it is fairly new. But I will check the connector.

Can anyone hazzard a guess? With the Hall Sensor code popping up as a guide?

So far I have;

Cleaned ISV
Replaced 02 sensor about a year ago but has only 2000 miles or so on it.
Replaced the DME Relay with 993 type.
Bitched and moaned about not solving the problem.

Anyone?

Cupcar#12

So far so good for me with the ignition switch replacement. i did have an issue with my Alarm control Unit as well (fault codes) which basically stranded me the other day (wensday evening)
basically it tripped into fault mode and refused to start the motor - this was rectified via leaving the pwr off for more than an hour and then locking and unlocking the car several times.
My mechanic and i think there is also a problem with this module since it has acted up before (refusing to allow the car to lock until it is reset, and i am replacing it with a new control unit this coming week.
however today i drove the car extensively without a fault so i am hopeful that it is fixed, another week will tell though until i can consider it solved.

on your Hall sensor fault a couple of ideas'
1. unplug and clean the hall sensor on the Disti
2. same for both knock sensors.
3. you have a 90' so i would do the TSB for the Air flow sensor and make sure your oil return pipe is secure and out of the way.
4. check your cetral electics connections to the DME relay (remove the CE board and reset the plug from below. make sure the board is secure when you replace it.
5. Ignition switchs are cheap $35-50 for the module - it is a PITA to get to though remove the left dash air vent and loosen the lower dash, unscrew the central informer to get to it.
double check the battery and ground connections as well.

hope that helps.

Smokin

Thanks for the tips Rob... I guess I might as well order an ignition switch... Seems like cheap insurance... You never know. I was also thinking about installing new coils to... Just as a preventative maintenance thing. They are almost 20 years old! (Hard to believe when you look at it!)

Thanks again!

Rick

Smokin

Well... My wife surprised me today. I warned her last night when she told me that she wanted to take the Porsche for a long drive today. I told her that I had been experiencing issues with it cutting out on me. Her response was to go get her tennis shoes in case we needed to walk anywhere! Well... She wanted to take about and hour and a half long drive out to see some covered bridges in Frederick, MD. Nice scenery everywhere... It's a neat drive if you are near here. Anyway... We were about half way there and the car craps out... We hit a bump and it started acting up. I nursed it to a weigh station that was closed. I tried swapping the DME relay... Nope... I disconnected the O2 sensor... Nope... Then I started taking connections apart and cleaning them and reseating them. BINGO! It fired right up. If I were smart I would have tried starting it after each connection reseat. I was happy to fix it and we were on our way... Until the next big bump... I pulled into a bank parking lot. All the while thinking it had ti have something to do with the split casing around the Hall Sensor connector. I juggled it around and pulled it straight up instead of having it leaning over. BINGO again! We drove to a little spot and had a nice lunch. I told my wife that I'd like to find a hardware store to get some electrical tape so I could hold the wiring in position. She looked down on the ground and saw a small length of nylon twine and asked if that would work. I picked it up and said we'd give it a try. After lunch we walked around a little and headed back to the car. I used the twine to hold the Hall Sensor cable up so that a bump wouldn't break the obvious intermittent fault in the wiring. It worked like a charm. We continued the trip and saw several covered bridges that were built in the mid 1800s. The weather was perfect all the way out and back. As I backed the Porsche into the garage the sky started clouding up and it started to rain about 15 minutes after we got back. My wife was glad to get away and see the sights and I was glad to finally (Hopefully!) find the culprit. Later this week or maybe next weekend I will take the wiring apart and look for the shorted wire in the harness. I'll post back with what I find.

Cupcar#12

update:no love....

replaced the ACU - no change
car will stop if the door is slammed or you hit the passanager seat hard -

i believe the issue is not with the ACU wiring under the passanger seat. which i will investgate tonight

anyone want to buy a cup car?.....i'm starting to get serious about moving on in my life.... i think......
(no there will be no discounts b/c of this issue)

Cupcar#12

Update #12

Possible solution:
the ACU Plug Connector #1 looks to be the most likely culprit. In a nutshell when the car was converted at Andial they bypassed and removed the ACU - when the connectors are typically removed you can break the ridge inside the connector that holds the wire in place allowing it to move when jarred disconnecting power momentatly to the relay in the ACU which sends power to the DME - there by cutting the ignition for a split second - Also they did a crappy job of reassembling it since they left wire strands hanging off of the connector and only used a small peice of eletrical tape for insulation - this also could be the issue - grounding out the pwr to the DME -

Fix -
order new connector - replace old plug
order new wire connectors and redo plug wiring
reinsulate 2 wires used to bypass the immobilizer
Bypass immobilizer for time being - retest car
redo all harnesses under pass seat - insulation and friction tape wrap as orignal.

Crossing my fingers again but this one makes sense - since the issue was very intermitiant however frequent enough to be a real nusance -
2. i have removed and replaced the seats numerious times and i could have disturbed something
3. i have had some issues with the alarm before - reseating the connector normally cleared up any issues - which would make the ignition cut off possibly worsen.

Crossing my fingers but i feel pretty good since i actually found something that was repeatable for stalling and cutting the ignition.

keep your fingers crossed...
i'll report back in a couple of days

Smokin

Two Words..... YEEEEEEEE HAAAAAAAAAA!!!!!

I FINALLY fixed the Hall Sensor code issue along with the cutting out when going over a bump! (Thanks to my wife bringing her tennis shoes! If we wouldn't have taken that trip I don't know how long it would have taken me to find the root of the problem!)

I knew my problem was in the wiring going to the Hall Sensor. I knew that when my problems disappeared when I tied the wiring up next to one of the spark plug wires. This kept the wire still and kept the connection constant. So.... Here's what I did today....

A few years ago (yes it has been that long) I noticed that the rubber shielding around that connection was split. It looked like it was okay inside so I figured that I would neatly wrap it with electrical tape to keep it closed. That has hidden my ultimate problem for over 2 years! I decided to unwrap my prior fix and cut the rubber covering off. What I found kind of shocked me. The PO (or someone) had used crimp connectors to connect all three wires just before the connection. They used heat shrink tubing over it so it looked stock after a few years of age. I went ahead and cut and peeled it off expecting to find a stock shorted wire. I found the crimp connectors instead. One of the connectors fell off in my hand. The other (Ground wire?) was hanging on by just one or two strands of wire. I went ahead and cut the connector off and stripped back the insulation on the covering and the wires. I got my handy soldering iron out and soldered all the wires back together instead of using the crappy crimp connectors. I used heat shrink covering on all the wires and then over all the wires. I finished it all off by wrapping the whole assembly tightly with self sealing/self vulcanizing heavy duty rubber tape. The stuff binds to itself and can't be torn apart after 24 hours. (Supposedly) Anyway... I cranked it up after connecting the battery and it purred like it never has before. I let it idle for about 15 minutes and then went out for about 30 minutes and drove it like I stole it. What a difference. The slight hesitation was gone when I blap the throttle... I couldn't make it stall out with the A/C on... Something it always used to do! And when I brought it back and ran ScanTool... The Hall Sensor code was there... But after clearing it... It would not come back! I did, however, come up with two codes that have been there for a while.... I have code 41 (Condenser blower motor) and code 45 (Inside sensor blower motor)... The weird thing is... Everything related to the A/C / Heating systems is working great! I changed the receiver/dryer two years ago along with the schrader valves and it still blows ice cold. So I am kind of stymied on that one... A low priority issue since everything works well. But I will track it down eventually.

So.... My Hall Sensor code is GONE and my Porsche runs like it never has before. I'm a happy, happy man tonight! Just thought I would share the experience in case anyone else might have the same symptoms. The way it is made.... I would venture a guess that there will be a large percentage of people who read this thread that are having the same problem. I hope this helps out others...