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YOUR RESEARCHQuestion on replacing ignition switch
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Install couple of days ago
Performed · outcome unconfirmed
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Performed · outcome unconfirmed · Original poster
Fuel pump is brand new and installed a couple of days ago with electrical and fuel hose connections made.
Leading evidence: 'Install couple of days ago' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check orientation of the female slot' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Performed · outcome unconfirmed · Original poster
I've replaced the AOS and fixed the crumbling HVAC vent foam, so in comparison to them this seems relatively easy!
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Performed · outcome unconfirmed · Original poster
At some point the starter assembly on my 1999 was swapped for a later one (it seems like Porsche changed the design in 2004).
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No difference cranking the engine, still not moving off 0 psi.
I am the original owner of a 1999 996 with a build date of Sept. 1998. My frunk lever is cable actuated and will not engage. I've read elsewhere that even though the cable is manual, there is some electronic component to it that will keep it from engaging if the ignition switch is bad. I think mine is bad, it was really difficult to turn on the other day and I finally got the car running. Now it won't start and stay running and the battery is fully charged.
My question is: if a replace the ignition switch on this car, will I need a new key? I've read of people swapping out the switch, but no one ever says "Oh, and you'll need a new key" or "The old key will work just fine" or "The switch will come with a key". I've done a lot of work on the car, but never replaced an ignition switch and have no clue.
You are only replacing the electrical part of the ignition switch. No need for new keys. Search this forum for replacing the electrical part of the ignition switch...several good write ups.
Many thanks for the clarification; I've seen the write-ups and it seems pretty straightforward. I've replaced the AOS and fixed the crumbling HVAC vent foam, so in comparison to them this seems relatively easy!
Ignition switch is a really easy DIY especially compared to the AOS replacement. Talk about easy I did my 996 SuperCup, took off drivers door, obviously no AC or other dash components took me all of 15 minutes😀 my street cars a bit longer.
Rich
Super easy you just need to be able to contort your body upside down under the dash :P). I've done it twice now! And you'll need a very small (eye glass small) screwdriver to unscrew and screw the set screws. Check out YouTube many videos on how to do it.
Okay, learned something VERY important on this journey, there are TWO different starter assemblies for the 996, an earlier and later version. I have a 1999 996 and gave the parts person the VIN number for the car; they sent me this starter switch:
You'll notice that the female slot is perpendicular to the two side tabs that orient the switch into the assembly.
This is the inside of my assembly with the key in the OFF position:
The male post is on the same line as the two side slots. If you click the earlier switch into the wiring harness, the dash lights come on.
After I figured this out, I searched pictures of the switch where the female slot was on the same line as the side tabs.
This switch goes into the assembly correctly and the dashboard lights don't turn on until the key is turned.
There is confusion on the part numbers, as you see in the URO box I received, the part number is: 4B0905849
When searching for parts, sometimes you get the above number and sometimes you get this number: 4A0905849B
At some point the starter assembly on my 1999 was swapped for a later one (it seems like Porsche changed the design in 2004).
So, my
strong
advice is to not rely on you car's VIN or manufacture date. Crawl under the dash, or if you have mechanically inclined 10 year old, have them to it. Once the hidden micro-screws on either side of the switch are loosened, pull the switch and check the orientation of the female slot. Perpendicular to side tabs - 4A0905849 (earlier version). In line with side tabs - 4B0905849 or 4A0905849B (later version).
If I have any of this backwards, I'm sure someone will correct me.
The 4
B
0 905 849 version is for 2004 and newer. The cylinder body doesn't have the step down that the A version has so it's too fat to fit into the ignition switch on earlier models.
I know most of this thread is about the ignition switch, but I thought I would jump in and provide advice on the frunk lever. Your MY99 build 996 will have a true manual cable to open the frunk. (#11 in the diagram) In MY01 cars, Porsche moved to a electrically actuated system (part #19 in the diagram).
Now, for security, if the car is armed or if the car is in motion, the the release lever assembly has an electrical pin that LOCKS the levels. Hope that makes sense.
Thanks for this schematic; I know this is off topic a bit from my original post but one quick question. I have a loop that looks like the end of #12 that extends out of the inside door panel when you open the passenger door. I have pulled on that to no avail. Should that open the frunk? If so, I'll get more aggressive with it. The loop is very thin and it feels like you're going to sever the end of your finger pulling on it. I'd have to slip a rod through it and pull it like a "T" handle to put more pressure on it.
On the original topic, after installing the new switch the car still won't start; it does a quick attempt and stops, so I'm thinking I need to replace the starter?
No, that's the manual release for the fuel filler door.
IMHO, it's usually NOT the started. The starters on these cars are very robust. You NEED to get a Durametric scanner and see if it's throwing any codes.
It could be something simple like a Crank Position Sensor. (common culprit on NO start situations), but it also could be something most complex like a faulty fuel pump.
To rule out the CPS, try to start the car and watch to see if the TACH needle is moving when cranking. Report back.
I'm out of town but will put it on my code reader when I get back next weekend and will report back.
Interesting about the starter because I had the original fail with less then 30K miles on it. I was out of town nowhere near a Porsche dealership and they had to bring one in overnight. The car only has 41K on it at this point so hopefully you're right!
Maybe an anomaly?
Been on the forums for more than a decade and in my experience the starters are pretty durable - do they fail? Absolutely! But unlike others things on these engines that get a lot of press, the starters aren't among them.
I've changed out starters on other cars, but not on my Porsche 996. Shhhhh... let's be quiet because my '99 still has good hearing and would love nothing more than to have my hands on it. hahaha
Your 996 is being good; mine is usually but right now is being a PITA. Frunk won't open, car won't start. 3,000 pound lump of metal with 41K miles. Sheesh!
I have a 356B and changed the starter on that last year which was
interesting
. Once I decoded the mystery of the top bolt (someone had welded a piece to the bolt head so the socket wouldn't fit over it. I had to buy a borescope to figure that one out! But after that, and figuring out another secret of assembly, it went pretty fast.
What does it sound like when trying to start your car? Maybe post a video?
A starter doesn�t actually start your car-it only turns the engine over slowly, but fast enough for air and fuel to enter the cylinders and the spark plugs fire at the right time when the computer gets the right signals from the DME, approved by the security system (alarm), after the CPS (Crank Position Sensor) tells the DME where the pistons are actually located.
A bad starter turns the engine too slowly or not at all. Sometimes you turn the key and nothing. Sometimes clicking. Similar to a bad or low battery. A starter�s failed bearing sounds like a screaming frog.
But if the starter is tuning over the engine, but the engine won�t catch, it�s probably not the starter.
When I get back home next weekend, I'll post a video. It's a quick attempt to crank, and nothing. Dashboard lights are on, there's no clicking from anywhere.
This whole process started when I turned the key and it was REALLY difficult to turn, but it did start. I drove it a few days with no problems and then backed out of garage one day and it stopped dead; I thought maybe I stalled it since reverse in this car is so unforgiving (and I might have) . So I don't know if it stopped on its own or just stalled. At that point I got the quick attempt to crank behavior. Then went down the starter switch rabbit hole and finally got the right switch installed, but same behavior.
It's been years, but I had a 99 early build car with starting issues. I also replaced my starter elec section and it got better. However, there is another failure mode with the alternator "Y" cable. This may be your issue as well. Search around for alternator Y cable replacement. It's not a real hard job. Disconnect the battery first, as there is a heavy cable involved. Once I did the Y cable, my car started much quicker every time.
https://rennlist.com/forums/996-foru...plified-2.html
Sorry this has been so long; too much traveling and no time to focus on this. I'm also still dealing with the frunk issue but that's another thread (literally).
I put a code reader on it and it came back with 0 codes.
I'm attaching a video where I tried to start the car 2 times so you can hear what it's doing.
I tested the battery and it is at 12.08V.
This is what my Boxster S sounded like when the fuel pump stopped working. The starter and battery are good. The engine turns over, catches a bit (spark plugs are firing and the fuel is igniting), but then fails. If you keep trying to start it and it catches less and less, then it�s probably your fuel pump because right now the injectors are able to deliver some fuel. If the fuel pump is going out, the injectors will run out of fuel, and all it will do is crank.
I would not hold the key in the start position for more than 5 seconds at a time, and wait 20 seconds between attempts. There�s noise killing your starter and battery. And in fact, if you have a battery maintainer, I would keep it connected throughout all of this.
Many thanks for the reply! I have the battery on a tender most of the time so it should be good. I've only tried to start it about 10 times with the current behavior so the starter should be good as well. I'll find a fuel pump and we'll see what happens.
Thanks, I'll pull the fuel pump relay and test that too. I'm assuming the fuel pump is in the tank which is in the frunk which I haven't been able to figure out how to access yet since it stopped opening last month.
Luckily I have other cars that actually run!
Okay, getting back to this and have the frunk figured out and under control. Car still has same non-starting characteristics (I think there's a video in this thread somewhere showing the behavior). At this point I have:
1. Replaced the ignition switch
2. Replaced the fuel pump relay
3. Replaced the fuel pump.
4. Installed a brand new battery (it was about 2 months over 4 years)
5. When I try and start the car, the tach moves up to about 10 on the dial and then the engine cuts out.
I bought an Autel Scanner MaxiCOM MK808S to scan the car for codes and ran it (admittedly right out of the box once I registered it, so nothing advanced). The only engine related code I'm seeing is P0102. I cleaned the MAF with CRC MAF Cleaner, reset the code, rescanned it and the code was gone.
Car still not starting so, the journey continues.
I'm open for suggestions.....
I've never done it on this car before and when I tried with my gauge, I got 0 psi. When I looked more closely at the container the fuel pressure gauge came in, it says "Will not work with
Bosch, CIS Jetronic, TB System on GM vehicles".
No idea why; I'm attaching a picture of the Schrader valve which looks normal but I'm guessing the fitting on the gauge isn't depressing the valve stem.
I looked around online a bit and it seems like I might need an adapter but I haven't found one. Here's a picture of the valve:
Is there an adapter or what kind of fuel pressure gauges are others using on a 1999 996?
Also, for what it's worth, I tested the fuel pump fuse and the fuel pump relay and they are good. Fuel pump is brand new and installed a couple of days ago with electrical and fuel hose connections made.
However, when I turned the ignition on and took the small end of a screwdriver and depressed the schrader valve stem, I didn't get a pressurized spray at all. It was more of a sad drip.
So, 0 psi could be accurate. I might open up the fuel tank again in the morning and make sure that electrical connection is solid; it sure felt like it when I installed it.
Don't jump to conclusions. Years ago working on BMW's, found out that just turning the key on does not activate fuel pump. This is done for safety reasons. Engine needed to be cranked, ECU saw engine rotation via CPS and activated fuel pump. So, I would crank the motor with a gauge on rail and than see what is going on.
Sorry for reviving a dead thread, but hoping someone can confirm the above. I have an '01 turbo, does that mean I need the 4A0905849B part? I'm unsure because it's nowhere near as widely available as the later "4B" version. A bunch of sites show the "4A' as discontinued.
This is a source reference. Confirm exact model applicability in the original material.
