Oh crap. What should I do? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

texomawaves · 10-21-2010, 11:36 AM

Here's what I did recently... I bought the Durametric, and showed Cyl misfire #5. So... I swapped coil pack between cyl 5 and 6 and guess what??? The next CEL code threw a Cyl misfire in number 6. Bingo!!!

So...

1. read your code on the Durametric
2. swap coil packs on adjacent cyl AND...
3. swap plugs on OTHER adjacent cyl
4. clear the Durametric code
5. drive car, run engine up to the 4k+ RPM
6. let engine cool, drink a beer (or two)
7. read the code again and see which cyl the problem follows
8. order parts
9. take girlfriend out to dinner

This procedure took me an hour or so. I'm assuming you have ignition issue, and guessing a fouled plug. My coil pack issue wasn't rpm related, it was intermittent. I hope this helps.

Topless · 10-21-2010, 11:52 AM

"Does anybody have any suggestion on how I can troubleshoot the problem and identify what's causing it?"

Jack up your car, pull the spark plugs and inspect the plugs and coil paks. The misfire cyl spark plug tip will be discolored (usually black or wet) compared with the other 5. Inspect the coil pak on the offending cyl and look for cracks or signs of arcing. Replace failed parts. Easy breezy.

The Durametric is nice but any simple $60 OBDII reader will also give you misfire codes that identify which cyl. is the problem.

texomawaves · 10-21-2010, 12:01 PM

One simple thing I forgot to mention... stop by Autozone and get them to read your code with their Actron. Not as detailed as a Durametric, and dont think it can clear codes, BUT you might get an early indication while you're waiting on your $300 Durametric to arrive in the mailbox

Mike_Yi · 10-21-2010, 12:45 PM

I don't have a CEL so AFAIK, I won't have a code.

I do have an AutoTap, which is supposed to work on all poast-'98 cars. So that should give me diag info. I'll try it this weekend.

Mike_Yi · 10-24-2010, 12:52 PM

I hooked up the AutoTap today. Even though it doesn't show a whole heck of a lot on this car, it did show me two codes. I'm getting
P1313 - misfire, cylinder 1, emission relevant
P1316 - misfire, cylinder 4, emission relevant.

So at least I know the cylinders involved right now. I still have no CEL, and it seems to be running fine now. Looks like I'm going to have to swap the wires and plugs and see if I get any more problems. I'm a bit worried that I'm not going to find anything since the car is running fine again.

Do you guys think it could have been bad gas? I filled up just before I got to the track. So I probably drove about 30 miles after filling up before the problem. I filled up again when I got home and haven't driven it much, but probably about 30 miles give or take.

Mike_Yi · 10-27-2010, 04:33 PM

Well, it died today. I've had to drive it to work even though I haven't fixed the problem. It's been running fine though (I've been avoiding high revs). Today, on the way to work, it started running rough at lower revs. When I exited the tollway and pushed in the clutch, the car died. I restarted it and it just ran rough. Something was making a squeaking noise (it sounded like an exhaust shroud squeaking). I turned off the road, shut it off, and coasted to a safe place. Waiting for a tow truck now.

The plugs are 4,000 miles old, the MAF and O2 sensors are about 15k miles old. Not sure what I'll find out.

Reborn996 · 10-30-2010, 03:34 PM

When you changed the plugs did you do coilpacks too? How many miles on your car? If you have 40k or more and are on the original coilpacks I would have them changed. I have had two other Porsche's (996 and Cayenne) with higher miles and in both cases the coilpacks were shot. I do not think they are that much money and should be considered a wear item every 40-60k in my opinion. When they start to go it can be very intermittent and it is just better to replace them every couple of years. IMHO

Topless · 11-01-2010, 07:06 AM

Quote:

Originally Posted by Topless

"Does anybody have any suggestion on how I can troubleshoot the problem and identify what's causing it?"

Jack up your car, pull the spark plugs and inspect the plugs and coil paks. The misfire cyl spark plug tip will be discolored (usually black or wet) compared with the other 5. Inspect the coil pak on the offending cyl and look for cracks or signs of arcing. Replace failed parts. Easy breezy.

The Durametric is nice but any simple $60 OBDII reader will also give you misfire codes that identify which cyl. is the problem.

The logical next step?? Or... take it to your favorite local mechanic. My money is on cracked coil paks.

Mike_Yi · 11-01-2010, 05:01 PM

You were all wrong. It's a bad main bearing.

Not sure what I'm going to do, but I suspect I will be selling the chassis and eating what I owe on the car rather than putting thousands into the car and having no guarantee that it will be any better than the car is right now.

Steve Tinker · 11-01-2010, 05:40 PM

I feel for your predicament having a major breakage like that. I think Porsches fitted with the M96 engine that are tracked really need the deep sump kit that helps prevent oil starvation under high cornering loads.....
As a matter of interest, how was the main bearing damage diagnosed?
You say that the car has been "running fine" after the initial vibration & rough running - I would have thought that you would have heard a bad main bearing, even at low revs.

Mike_Yi · 11-01-2010, 05:50 PM

Quote:

Originally Posted by Steve Tinker

I feel for your predicament having a major breakage like that. I think Porsches fitted with the M96 engine that are tracked really need the deep sump kit that helps prevent oil starvation under high cornering loads.....
As a matter of interest, how was the main bearing damage diagnosed?
You say that the car has been "running fine" after the initial vibration & rough running - I would have thought that you would have heard a bad main bearing, even at low revs.

I didn't ask how he determined it was the bearing, but he did say it was scored. He said he didn't look at the crank. Not sure how he got a look at the bearing, especially since they didn't start looking at the car until late in the afternoon. I'm going to ask him tomorrow.

When it did finally stop running, I did hear a bearing noise.

Everybody told me that I only needed a deep sump if I had slicks. They said you wouldn't generate the Gs with street tires that could cause scavenging. I guess they were wrong.

Jake Raby · 11-01-2010, 06:10 PM

Actually the engines that fail on the track only appear to fail from starvation...

Most fail because their oil temperatures soar and the oil doesn't have the capability to protect the components or maintain pressure at these temperatures that are generally 250-265 degrees.

Here are some examples from one of our test cars running a bone stock 3.2, just purchased in May of this year from Porsche. The oil was Mobil 1 10/40 for these tests, we used these for baselines for ongoing lubricant development.

When an engine dies due to a lack of oil pressure from overheated oil, the symptoms will fool many into believing the issue is starvation. This data suggests oil that is being cooked well beyond the point where pressures drop off significantly.

That said, I may have a buyer for the car with the blown engine.. I have a wait list of those who are looking for a car to equip with an upgraded engine who don't care if the engine is currently scattered.. It won't bring much, but at least you can move it.