What a day, now to figure out what's happening with the car

Was driving today and saw the CEL light start flashing. Trying to get off the freeway and to pull over, I see a bunch of smoke coming from the engine bay. A couple seconds later the car shut off and wouldn't restart. Luckily by the time that happened (less than a minute for all that) I was able to get pulled to the shoulder. got the car towed home and ran the codes for CEL and it's a plethota. P0301 P1225 P1227 P1230 P1228 P1226 P1229 P1115 P1117 P1118 P1119 2000 911 C2 6 speed 97k on the clock Eek, gotta see what these all are. And try to determine what would cause that and hope they was nothing additional to find. And, did I mention the tow truck blew a tire while taking the car and I home?

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I would first see if you could find the source of the smoke. That could possibly be the root of all the issues. P0301 Cylinder 1 missfire P1225 Cylinder 1 fuel injector - below limit P1227 Cylinder 2 fuel injector - below limit P1230 Cylinder 5 fuel injector - below limit P1228 Cylinder 4 fuel injector - below limit P1226 Cylinder 6 fuel injector - below limit P1229 Cylinder 3 fuel injector - below limit P1115 Oxygen sensor heating ahead of TWC - Bank 1 P1117 Oxygen sensor heating after TWC - Bank 1 P1118 Oxygen sensor heating after TWC - Bank 2 P1119 Oxygen sensor heating ahead of TWC - Bank 2 It looks as if the one major things these all have in common is a rely labeled "Ignition/Oxygen/Injector Relay" located on relay support 2 and is powered by fuse C2 which is a 30 Amp Maybe that may give you a starting point in your Diag?

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definitely a place to start what would cause that fuse to blow?

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A short anywhere in the circuit. That's why helping to identify the smoke may point you in a direction. Crappy example - but lets say you pop the hood and notice the serp belt broke. it would be possible that the belt tore up some wiring at the moment it snapped which would cause a short and all these codes. Not saying that is your issue, but the cause of the smoke is either your beginning of the failure or a side effect of the failure. either way, it gives direction - hopefully.

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well, the fuse is definitely blown. now to figure out why. Not sure where to even start at this point. not too long ago, found a small coolant leak from a hose. Replaced that and all was good. Didnt notice any more leaks. Could a small leak like this somehow cause the fuse to go? Maybe there is another one, car is 18 years old. The coolant level in the overflow is 3/4 now, so somewhere its leaking or evaporating again.

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Well, I would start with a good visual inspection under the hood (what little can be seen at least). i would look at the O2 sensor wiring and make sure it all looks in tact and not damaged (melted on the exhaust). If a visual inspection looks o.k. and you can't identify where the initial smoke came from, pop another 30 amp fuse in and see what happens. If it dosen't blow immediately - that will suck because the problem is intermittent and will be a pain in the butt to diag. If it does blow, then a multi meter and diagnostic will have to start. You may also want to swap the relay with another identical one too. Euro cars are known to have crappy relays that can short internal.

Good advice. Instead of a regular fuse, you may want to use a smart fuse instead. When the fuse blows, it will light up (built-in LED). If the fuse blows again, I would start unplugging each O2 sensor one by one and see if the LED goes out. If it does, it's whatever you just unplugged creating a short. You can then unplug the two big round canon connectors one by one in the right side of the engine bay.

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if that LED fuse blows, wouldn't the metal connector piece inside it melt? Therefore pulling the shorted O2 sensor wouldn't make a difference as the circuit is already compromised at the fuse. what are the cannons you speak of in the rights side of the engine bay? Would it be safe to pop another fuse in without knowing the reason it blew in the first place? Is it common enough that a fuse just as lived its life and fails without cause? thanks

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I was waiting for Ahsai to chime in. His knowledge and help is invaluable. Yes it is safe to pop another fuse in. Just don't throw a bigger one in hopping that will fix it. The fuse is designed to blow if the problem still exists. That is its whole job in life. And no - fuses don't have a life cycle. There is no moving parts to wear out.

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I will try it, just didnt want to cause more issues. Obviously something had to cause it to go, frustrating to try and find that. I was more wondering if a fuse generally just blows and is the cause of the short. Maybe defective or something.

I would pull cylinder 1 coil and inspect it closely. The reason I say this is that your flashing check engine light indicates a misfire. You have a cylinder 1 misfire code also, but no other misfire codes, but fuse C2 powers all the coils so if the misfire code set from the fuse blowing, you should have codes for all 6 cylinders misfiring. My money says the #1 coil is shorted and that was the start of your issues before the overloaded 30 amp fuse blew and set all the other codes and causing the car to shut down.

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Very good point. My wiring diagram agree's with this statement. An easy confirmation to a fried coil could be if the fuse continues to pop when installed (or use smart fuses as Ashai described), disconnect coil #1. If the short goes away, there's your problem.

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good idea. I will have to look at that tomorrow most likely. To confirm, cylinder 1 is driver side furthest to back of car? Got to find a way to get the car from the driveway into the garage. Dont want to jack it up on an incline. the relay itself seems to function properly when I pulled it out and tested it.

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If the relay wasn't working the fuse likely wouldn't be blown. I guess it's possible there is a short between the fuse and relay, but in my experience that is rare. You could verify by pulling the relay and installing a new fuse. If it doesn't blow your short is on the other side of the relay which is most likely the case.

Wow...watching this realtime diagnosis is really great to see. THis is a great example of the power of this forum. I am not even the one this is happening to and yet...Thanks guys and TSG, hope its as easy as it seems.

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true, just figured I'd test it to be sure while I could. i put a new 30A fuse in and it blew immediately ion trying to start the car. It tries to turn over, but can't, not surprisingly one I saw the led on the fuse come on.

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it's amazing to see. again, thank you to those that can assist. tomorrow I'll see if I can pull the coil from cylinder 1. Have to find a way to get the car in the garage first. cylinder 1 is driver side, closest to rear, correct?

If the smart fuse (or any fuse) blows, that means there's an electrical path flowing to ground with very low resistance. This same path makes the LED light up. If you remove the shorted component that provides this ground path, the LED will turn off, then you know the component is thre culprit. Look at the right side of the engine compartment. Deep inside you will see two big round electrical connectors. Just unscrew and pull apart. One at a time. Check if the LED still lights up.

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what are these round connectors? Just curious pulled each one separately and turned ignition to on. Led came on while each was pulled.

Those connectors (actually one of them) contains the wires connected to the coils and injectors. I suggested this because these are very easy to reach and unplug. If the LED is still ON even after BOTH are disconnected, you problem is somewhere else. Could be the O2 sensors. You can just remove the airbox and unplug the O2 sensors one by one and keep checking the LED.

I crawled under and saw the coil pack. I'm not a genius, but something is telling me it shouldn't look this way.

You found it!

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is there a diagram for the O2 sensors? How many?

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retracted comment after noticed you found the source

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but wouldn't unplugging the other connectors have caused this short to disappear temporarily? The more I look at it, the tears appear to be in the rubber boot, not wiring. edit: maybe is wiring too after zooming in do you happen to know the size of socket needed to get those star bolts out? is there a diagram showing where the other end of the wires go? This doesn't appear to be part of the coil pack, but a wiring harness.

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when i zoom it that looks like rodent damage and i do see damaged wires not just the boot. Hard to tell by the picture but that does look like it is the coil connector and the wire looks to be black. The black coil wire is on the same circuit as fuse C2 so i think you are on the right path. I am not as familiar as other with the 996 wiring layout. But i too would have assumed that once the 2 round bulkhead connectors were discconected and the fuse led stayed light - that the problem would have then been inside the cabin. Again that assuming the 2 connector cut all links on the circuit between in cabin and engine compartment. The diagrams i have dont show those connectors so i dont know. Maybe someone else can chime in. however seeing the the picture you took i think that is going to be your issue. If that does find to be rodent damage, take a good look around for more damaged wiring and in the air filter and cabin filter housings. its 11pm on the east coast so i am off to bed. Hopefully i wake up in the am to some awesome diag info and a conclusion for you. Good luck.

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yeah, I started thinking the same when zooming in. I have never seen or heard of rodents here in my neighborhood other than rabbits. I will definitely be looking around some more. trying to track down where to buy this harness and a diagram of where the other end goes. Not finding anything on pelicanparts or suncoast porsche websites yet. thanks for the help.

The power to the coils and injectors come from pin4 of one of the big round connector called x59/1, which connects to relay #2 (ignition/O2 sensor), then to fuse C2. What if you remove relay#2 under the rear parcel shelf? Does the LED stays lit?

Your better bet would be to repair the harness or get a used set from ebay. A brand new one will probably be more than $1k.

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I will check that in the morning. I'll have to see how bad it is when I get the coil pack off and find the other end of that harness. Do you know where it might go and how easy it will be to get the harness out?

It's a pile of spaghetti https://www.ebay.com/itm/Porsche-99-...sAAOSwJK9bhrkO https://www.ebay.com/sch/i.html?_fro...rness&_sacat=0 You will need to remove the whole intake manifold to replace the whole harness. Btw, get the wiring diagram here http://arma.free.fr/porsche/996/GT3/...01999-2000.pdf The power comes from fuse c2 then to the ignition/O2 relay, then it splits into two branches: - to the coils and injectors via x59/1 connector - to the 4 O2 sensors via those rectangular red/grey locking connectors

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eek, I was hoping it was in pieces, not a complete harness. may look to get under there and see how bad it is and repair it connected to car

The socket for the torx bolts should be E10 or you can use a 8mm 12-pt wrench in a pinch. Btw, the x59/1 connector does cut all the wires to the coils.

I would repair the harness. When we do engine swaps here at my shop with used motors I always keep the old harnesses and cut the pigtails off for this exact reason, you just never know when one plug can be the difference between repairing a harness inexpensively versus replacing a harness for thousands. In our area this past year rodent damage has been rampant, so we are seeing more and more harness damage. If you have a good Porsche independent shop in your area swing by with that plug, you might be surprised with what they have. Heck, every dealership I have ever worked for had a box of old connectors around for stuff like this, so might be worth swinging by a dealership and asking a tech if they might have a harness out back they cut up.

NAPA lists the coil pigtail. Echlin EC506 is the part number. $63.00 retail.

Get some rat traps set up and catch that bastard before it causes more damage!

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Thanks. looks like the only way to be able to get up and reach that pigtail and cut it off and solder a new one on is by removing the header

Removing the header is not hard.

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For sure It doesn't, just a few bolts and ordering new gaskets. the trying to attach a new pigtail looks to be challenging as there isn't much room to work with under there.

I may have a harness.

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the full one or the coil connector?

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The coil connectors

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if you do, that'd be awesome. PM me and we can discuss thanks

I've got the full harness pulled from a 2000 C4 if you decide to go that route.

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If I do, I'll PM you. From what I hear, that's pretty invasive and means taking quite a bit apart. I dont see an other damage that would warrant replacing the whole thing yet

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PM sent

UPDATE: well this week, so far I've replaces all 6 coil packs, spark plugs and wired in a new plug/connector for the cylinder 1 coil pack. While at it, changed the fuel filter, oil change and replaced the radiator cap. it fired right up and ran great. then I get a couple miles away and stop, only to see the coolant leak wasnt the radiatoradiatas steam was coming from the engine bay. Looked around that area and sure enough some splatter. I went ahead and tightened the cap down as it seemed to have a few spins to go, hopefully that's all it was and not a leak somewhere else. I guess next step would be bleeding the system making sure no air is caught and then a pressure test. [Anyone know if you can rent/borrow these from autozone?] [Or what the approximate cost from an indy to test it? I dont really want to drive it that far to the closest indy]. what then? Water pump, expansion reservoir, thermostat? damn....was really hoping to be able to take the car on a road trip to SoCal, about 250 miles each way this weekend. Edit: the other oddity... the climate controls didnt come on, buttons dont work, no temp or fan speed, etc showing on the display. I will double check the fuse when I get back home and have a light.

I'd drive it around (close to home) and get it up to temp, stopping periodically to check for leaks.

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I'm about to do that on the way home. It's only 1.2 miles, but I figure I can drive up the street and such before going into neighborhood.

Clean off the coolant cap and the expansion tank so you can see if there are new accumulations of coolant. Check the part number on the coolant cap (should be -04) and examine the tank for leaks. Those are good places to start.

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Yup, just installed the new cap. Pretty sure it want tight enough. Also found a hose clamp that was a bit loose. Between tightening those both up, didnt notice any more leakage

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