CEL and misfires

[dcporsche99]

Hi,

Could use some help with a few codes please. :(

My car is a 1999 2.5 Boxster (Tip) with over 60K.

A quick history---my car had been sitting for a few weeks. I had it on a trickle charger for a couple hours prior. When I started 'er up I heard a ticking sound on the passenger's side rear. It sounded like a sticky lifter. Anyway, I warmed it up to operating temp and took the car out for a quick spin around the block. I got a flashing CEL w/c then turned solid (2X). The car also began to stutter and run poorly at low RPMs. I also got a whiff of a faint "burnt" smell when driving back home. My OBD II reader showed P302 and P1314 (re: misfire cylinder 2). From my research on the forum.....long story short, bought new Beru plugs and a few coilpacks for good measure.

Today, after 2 wks I finally had the time to change out the coil and plug (cylinder #2). The cylinder was dry and the plug looked like it did need to be changed. But the coil looked intact---although I will take a closer look. So, afterwards I reset the codes and started it up. Again, I heard a ticking, but this time on the driver's side. I warmed it up and I took it out for a test drive and these are my new codes below. Again, the car was running poorly and stuttering on idle.

Here are the current codes:

P300

P302

P304

P319

P314

P316

Any help would be appreciated.

Thanks in advance!!

-Dana

[Loren]

P0300 Misfire Damaging to Catalytic Converter

P0302 Misfire, Cylinder 2, Damaging to Catalytic Converter

P0304 Misfire, Cylinder 4, Damaging to Catalytic Converter

P1314 Misfire, Cylinder 2, Emission Relevant

P1316 Misfire, Cylinder 4, Emission Relevant

P1319 Misfire, Emission Relevant

Potential causes:

- Fouled, faulty or incorrect

- Contact resistance

- Loose contacts

Check spark plug connectors.

Resistance: approx. 2 k ohms

Check ignition coil(s).

Resistance between terminal 1 and terminal 15 at 20°C: 0.3 - 0.7 ohms

You might want to try an oil change too.

If you really have a stuck lifter or two this might be a cheap fix - short of removing and replacing the lifters.

If is is not one of the"easy" things you may need a PST2 or PIWIS to further diagnose mixtures and cam actuation and sensor readouts.

[dcporsche99]

Thanks Loren. Appreciate the quick response. :)

I will try to check the resistance on those items....although I have never done that before.

It's just weird that the other bank would pop up with codes when I didn't have that before I changed the plug and the coil pack. Throwing codes after having fixed one....what a PIA??

Edited April 11, 2008 by dcporsche99

[klueless7571]

I've had P0300 P0301 intermittently for about 8 months now. Took it in to local Porsche dealer a couple of times but they couldn't find any problems. Now I just use my Durametric to reset to codes whenever they pop up. But I think they are getting more frequent

Derek

[dcporsche99]

I've had P0300 P0301 intermittently for about 8 months now. Took it in to local Porsche dealer a couple of times but they couldn't find any problems. Now I just use my Durametric to reset to codes whenever they pop up. But I think they are getting more frequent

Derek

Hey Derek,

Thanks for the input....Sorry to hear that they can't find a problem, though I'm sure they were happy to charge you each time. Hope you can find out what the trouble is.

Found this online for you:

P0300 Misfire Damaging to Catalytic Converter

P0301 Misfire, Cylinder 1, Damaging to Catalytic Converter

Well, IMHO, I don't have too much trust in the dealership...unless of course I don't have a choice.

Anyway, why don't you try to change out the plug and/or the coil yourself and see if that fixes it??

Good luck with that. :)

[Chris_in_NH]

there are a few things i would do/check. first, i would double-check all the coil pack connections, especially on the cylinders that are misfiring. make sure the ignition wires are connected properly and snapped into the coil packs.

then i would run a bottle of Techron through the car. do this with a full tank of gas and after the tank of fuel is gone, change the oil (assuming you can get the car to run well using the MAF test below). if the car is completely undriveable even after the MAF test, i would still add the Techron and change the oil.

a failing MAF (Mass Air Flow meter) is a possibility. when the MAF goes bad, it starts sending wacky signals to the DME and can make your car run REALLY rough and/or not at all. a very easy test to do is to unplug the MAF's wiring harness, then disconnect the neg battery cable for at least 1 minute (this will reset the DME/ECU), re-connect neg battery cable (but not MAF's wiring harness) and go for a drive. if the problem is completely resolved (and you will know *instantly*), you need a new MAF. DO NOT skip the battery disconnect/connect with this test. you will also need your radio code to get the radio working again after the battery disconnect, so make sure you have it if your radio is OEM.

at 60K on an earlier car, the AOS (Air-Oil Separator) could be starting to fail. this is a fairly common failure and many people proactively install a new AOS to head-off a potentially catastrophic event. the AOS design has been 'updated' 5 or so times now. that's how bad the original design was. and that's what's in your car! (unless you've already replaced it) ;)

a failing AOS usually (eventually) produces 1125/1128/1130 codes (and misfires from the engine being fed oil), but who knows, maybe this is the beginning of AOS failure. it won't hurt to consider it.

you can check the AOS by opening up the throttle body and looking for more than just a misting of oil. you can also check the J-tube that connects the AOS to the throttle body for more than a misting of oil. my TB had a RIVER of oil in it. here's a pic:

if this is what your TB/J-tube looks like, it's time for a new AOS.

so that's what i would do and the order i would do it in. let us know how it works out!

[dcporsche99]

Thanks for your thorough advice Chris. Totally appreciate it!

Actually, I have the parts already for an AOS install for months now in the anticipation that I would eventually have to do this. I also have the parts to change out a leaky coolant tank. This CEL was not on my list to do. I was just waiting on some good weather to tackle the DIY of the other stuff.

Awhile back, I had CELs for 02 sensors (re: after I completed my DIY install of my aftermarket headers) and thought it might be the MAF. But I did notice that the MAF had already been changed out by the previous owner. So, I changed out the sensors and the CEL didn't pop up again until now (re: it's been approx. a year to date). Is there a possibility that the aftermarket headers that I installed is related?? Or is this just within the norm of Porsche ownership?? Don't get me wrong,...totally LOVE my car, but I haven't done so much DIY with any other cars....funny, even my SUV (Explorer w/ over 135K) hasn't given me so much unexpected $$ out of pocket...at least, it puts me back into perspective when I think of more mods that I want to do and realize that I should just keep my cash for times like this...... well, enough of this rant....I feel a little bit better now. :P

Thanks again.

-Dana

[1schoir]

...

Actually, I have the parts already for an AOS install for months now in the anticipation that I would eventually have to do this.

....

-Dana

Dana:

Before you tackle the AOS, make sure that you have a decent pair of hose clamp pliers to deal with the hose clamp at the lower end of the bellows.

I just replaced my AOS, using the aforesaid hose clamp pliers and plastic zip ties and it was pretty straightforward. If you position the car (and yourself) properly, it's not too difficult to access the bellows once the right rear wheel is off.

Where in NY are you located?

Regards, Maurice.

[dcporsche99]

...

Actually, I have the parts already for an AOS install for months now in the anticipation that I would eventually have to do this.

....

-Dana

Dana:

Before you tackle the AOS, make sure that you have a decent pair of hose clamp pliers to deal with the hose clamp at the lower end of the bellows.

I just replaced my AOS, using the aforesaid hose clamp pliers and plastic zip ties and it was pretty straightforward. If you position the car (and yourself) properly, it's not too difficult to access the bellows once the right rear wheel is off.

Where in NY are you located?

Regards, Maurice.

Hey Maurice,

Thanks for the reminder for the AOS DIY. Before I tackle that I'll make sure to go over the DIY online to make certain I have everything. Actually, I'm hoping that my CEL can be taken care of without doing that (re: either of those--AOS and coolant tank) just yet. I'd like to drive the car some before then.

I'm close to Stony Brook University. Maybe when I get to the AOS I'll send you a PM that'll say, "HEEEELLLLLLLLPPPPPPP" :P

[1schoir]

Hey Maurice,

Thanks for the reminder for the AOS DIY. Before I tackle that I'll make sure to go over the DIY online to make certain I have everything. Actually, I'm hoping that my CEL can be taken care of without doing that (re: either of those--AOS and coolant tank) just yet. I'd like to drive the car some before then.

I'm close to Stony Brook University. Maybe when I get to the AOS I'll send you a PM that'll say, "HEEEELLLLLLLLPPPPPPP" :P

Dana:

If you feel intimidated by the AOS and would rather do it by my house, let me know and I'll help you out, anytime.

Drop me a PM and I'll give you my phone number.

I'm in Freeport, a few blocks from the Meadowbrook and Sunrise Highway.

Regards, Maurice.

[dcporsche99]

Hey Maurice,

Thanks for the reminder for the AOS DIY. Before I tackle that I'll make sure to go over the DIY online to make certain I have everything. Actually, I'm hoping that my CEL can be taken care of without doing that (re: either of those--AOS and coolant tank) just yet. I'd like to drive the car some before then.

I'm close to Stony Brook University. Maybe when I get to the AOS I'll send you a PM that'll say, "HEEEELLLLLLLLPPPPPPP" :P

Dana:

If you feel intimidated by the AOS and would rather do it by my house, let me know and I'll help you out, anytime.

Drop me a PM and I'll give you my phone number.

I'm in Freeport, a few blocks from the Meadowbrook and Sunrise Highway.

Regards, Maurice.

Cool beans! I think I might take you up on that offer..... I'll let you know how this goes. I appreciate it!

Thanks Maurice!

-Dana

[Chris_in_NH]

Cool beans! I think I might take you up on that offer..... I'll let you know how this goes. I appreciate it!

Thanks Maurice!

-Dana

what is the car doing now? have you unplugged the MAF yet/reset the DME yet?

i understand that the previous owner installed a new MAF, but that doesn't mean it's not bad. ;)

Edited April 12, 2008 by Chris_in_NH

[dcporsche99]

Cool beans! I think I might take you up on that offer..... I'll let you know how this goes. I appreciate it!

Thanks Maurice!

-Dana

what is the car doing now? have you unplugged the MAF yet/reset the DME yet?

i understand that the previous owner installed a new MAF, but that doesn't mean it's not bad. ;)

Good point Chris. As for the MAF and TB, I have to take the hardtop off to get to it. I don't have time to get to that until next week.

Just finished changing out all the plugs, coils, and cleaning 'er up. I figured I might as well do them all since they were due for a change (re: over 60K on the clock). Actually, while I was checking cylinder #2, I did find that I had not connected the wire correctly to the coil (re: Thanks for the heads up on the "snap")....hence, my repeated misfire on cylinder #2. So, for good measure I made sure to hear and see the coil snap into place.

Having done this, should I now clear the codes via OBD II AND take off the negative cable from the battery to reset the DME?? Or will just taking the negative cable off from the battery do both?? I'd like to take it for a test drive in the morning. I still have to buy the Techron. Is there only one type?? Can I purchase this at Autozone or Walmart??

TIA!

Edit: BTW, that cylinder #1 plug was a PIA! Thank goodness for the swiveling ratchet head.

Edited April 13, 2008 by dcporsche99

[1schoir]

Good point Chris. As for the MAF and TB, I have to take the hardtop off to get to it. I don't have time to get to that until next week.

Just finished changing out all the plugs, coils, and cleaning 'er up. I figured I might as well do them all since they were due for a change (re: over 60K on the clock). Actually, while I was checking cylinder #2, I did find that I had not connected the wire correctly to the coil (re: Thanks for the heads up on the "snap")....hence, my repeated misfire on cylinder #2. So, for good measure I made sure to hear and see the coil snap into place.

Having done this, should I now clear the codes via OBD II AND take off the negative cable from the battery to reset the DME?? Or will just taking the negative cable off from the battery do both?? I'd like to take it for a test drive in the morning. I still have to buy the Techron. Is there only one type?? Can I purchase this at Autozone or Walmart??

TIA!

Edit: BTW, that cylinder #1 plug was a PIA! Thank goodness for the swiveling ratchet head.

Dana:

Disconnecting the negative cable from the battery for one full minute will do the trick.

You can pick up Techron at Autozone, as well as Pep Boys or Advance Auto Parts on Long Island. It comes in two sizes. The smaller size is sufficient for the size of a Boxster gas tank. As Chris said, it's a good idea to run the Techron just before an oil change.

Regards, Maurice.

[dcporsche99]

Good point Chris. As for the MAF and TB, I have to take the hardtop off to get to it. I don't have time to get to that until next week.

Just finished changing out all the plugs, coils, and cleaning 'er up. I figured I might as well do them all since they were due for a change (re: over 60K on the clock). Actually, while I was checking cylinder #2, I did find that I had not connected the wire correctly to the coil (re: Thanks for the heads up on the "snap")....hence, my repeated misfire on cylinder #2. So, for good measure I made sure to hear and see the coil snap into place.

Having done this, should I now clear the codes via OBD II AND take off the negative cable from the battery to reset the DME?? Or will just taking the negative cable off from the battery do both?? I'd like to take it for a test drive in the morning. I still have to buy the Techron. Is there only one type?? Can I purchase this at Autozone or Walmart??

TIA!

Edit: BTW, that cylinder #1 plug was a PIA! Thank goodness for the swiveling ratchet head.

Dana:

Disconnecting the negative cable from the battery for one full minute will do the trick.

You can pick up Techron at Autozone, as well as Pep Boys or Advance Auto Parts on Long Island. It comes in two sizes. The smaller size is sufficient for the size of a Boxster gas tank. As Chris said, it's a good idea to run the Techron just before an oil change.

Regards, Maurice.

Great! Thanks for the info Maurice! Will do.

[dcporsche99]

Good point Chris. As for the MAF and TB, I have to take the hardtop off to get to it. I don't have time to get to that until next week.

Just finished changing out all the plugs, coils, and cleaning 'er up. I figured I might as well do them all since they were due for a change (re: over 60K on the clock). Actually, while I was checking cylinder #2, I did find that I had not connected the wire correctly to the coil (re: Thanks for the heads up on the "snap")....hence, my repeated misfire on cylinder #2. So, for good measure I made sure to hear and see the coil snap into place.

Having done this, should I now clear the codes via OBD II AND take off the negative cable from the battery to reset the DME?? Or will just taking the negative cable off from the battery do both?? I'd like to take it for a test drive in the morning. I still have to buy the Techron. Is there only one type?? Can I purchase this at Autozone or Walmart??

TIA!

Edit: BTW, that cylinder #1 plug was a PIA! Thank goodness for the swiveling ratchet head.

Dana:

Disconnecting the negative cable from the battery for one full minute will do the trick.

You can pick up Techron at Autozone, as well as Pep Boys or Advance Auto Parts on Long Island. It comes in two sizes. The smaller size is sufficient for the size of a Boxster gas tank. As Chris said, it's a good idea to run the Techron just before an oil change.

Regards, Maurice.

Great! Thanks for the info Maurice! Will do.

As an update:

Car is running well since I did the change out of the plugs and coils. But, I still have to get some Techron and change the oil. BTW, I was hoping to go with a thicker oil. I noticed that when I changed the oil & filter last season with 0W40 that my little drops were more frequent after a spirited drive. Any suggestions would be appreciated. edit: Looked up Toolpants' thread that entertained the idea of the non-Porsche approved Mobil 1 15W50 w/c I will try out this season.

Also, I had my bro help me take off the hardtop last weekend. But, it was only just yesterday that I was able to open up the engine compartment to take a good look. I was happily suprised to find that the compartment was clean (TB..etc.) and that the previous owner had already changed out the AOS to the updated version. So, I'll hold on to the AOS replacement & parts for the future since I've read that it holds up on the average of 50K? Is that right?? Thanks for the offer Maurice! Hope the offer still stands in the future ; ) edit: looks like I may have spoke to soon---just double-checking---w/c configuration is the updated version?? From Mike Focke's website I understood it to be the vertical (circular part) as the updated and the horizontal config as the outdated version. I found some conflicting info so, please do let me know.

Anyway, the only thing that I replaced yesterday was my air filter (w/c I had ordered over a year ago and almost forgot I had). Anyone have a "True Flow" filter?? I noticed that it had been oiled / conditioned and so, I wiped off the excess before I installed it. Hopefully, it doesn't screw up my MAF. edit:It was suggested that I go back to the stock air filter. After reading a few threads, I concur with his suggestions. Thanks Maurice!

Thanks in advance.

Edited April 21, 2008 by dcporsche99