Correction. Found the oil pressure switch just below the fuel rail. It looks like the wire going to the switch has had a previous repair with a crimped splice. Maybe the splice is bad and the circuit is open. I'll get out there in a bit and ohm things out. I looked at the wiring diagram and it appears that the switch passes a ground to the DME when the oil pressure is ok. Shouldn't I be able to jumper this wire to ground to test the functionality?

I checked out the splice with a multimeter and it was ok. I then jumpered the switch wire to ground and started the car. The oil light was illuminated on the dash. While the car was running I disconnected the jumper and the oil light went off. So a ground causes the lamp to illuminate. With the switch wire disconnected, the car kept running, poorly, but running. Lots of vibration and missing. I need to check the voltage at the switch itself. Reconnecting the wire to the switch did not cause the oil light to come on. I need to go pick up some spark plugs to replace the carbon fouled ones.

Request for some help
 

I got all the spark plugs out and found the plugs in cylinders 1, 2, and 3 were covered with carbon. I found cylinders 4, 5, and 6 covered with gasoline. Is it possible that 3 injectors got stuck open? Or is this lack of spark in one side of the engine? Thanks in advance.

I wonder if the flooded plugs could be due to a bad fuel pressure regulator which I just replaced? I've measured 12 volts at each of the coil pack connectors. I guess it is possible 3 coil packs failed, but they all ohm out ok. I'll check spark from the actual coil packs tomorrow with a spark tester before replacing any plugs. Going to do another fuel pressure test today to see if there is a chance of injectors leaking.

I would verify spark on all packs AND plugs (put the plug back in the pack, ground the body of the plug with a jumper and watch for spark while cranking). That will tell you for sure if you are getting spark.

Took your advice and tested for spark exactly as you suggested. All spark plugs are firing. Even with carbon and gas on them. I did a fuel pressure test. 3.8 bars with key on engine off. Dropped to 3.4 bars after 30 minutes, 3.0 bars after an hour, and 2.0 bars after being left overnight. So if there is a fuel injector leaking, it's a slow leak. I guess the next step is to put a noid light on each of the injectors cables and check them out. After that, I'm down to the injectors themselves.

I'm really impressed with your deductions and reasoning and the steps you're taking to get there. It is looking more and more like your injectors are the issue. Either dirty or leaking. You know you have compression and spark...so it's gotta be air/fuel related.

If you end having a leaky injector, you may want to send the six of them to get serviced, I had pretty good experience with RC Engineering as they charge less than $25 a piece and they are returned within a couple of days

RC Fuel Injection

Good luck!

Name this tube
 

I did the noid test and found to my dismay that all injectors were pulsing. Not really my dismay, but an end to the quest. But while I was underneath the car wresting to get to the injector plug on cylinder 4, I found the tube shown below unhooked at one end near the driver side front of the engine (maybe the PCV valve?). The other end goes under the plenum and somewhere below or into the manifold (possibly to AOS). Fairly rigid tube, not rubberized. I hooked it back up by feel to what I guess is the PCV on the drivers side crankcase cover near the firewall. I could not see the ends from above or below. So before I get all excited and reassemble everything, can someone tell me what this tube is and could it be causing a vacuum leak? No, I did not see smoke in this area from the smoke machine.

Sorry for the big picture and it's cockeyed angle. I'm referring to that small bend of tubing hiding there above the spark plug hole in the crankcase. Thanks for the help!

After more reading, it looks like it may be the crankcase vent (breather) tube that connects between the PCV valve and the AOS. If it was disconnected, it may really screw up the air/fuel mixture at idle. Can anyone verify the location of that tube?

Tada,

I am not sure how old is your car, but on my '07 the "accordion type" hose (link below) was cracked, loosing vacuum (and making a mess..), this hose connects the PCV located under the driver side intake plenum to the AOS

I also remember that when I remove it, it also pulled a connector that is in the same area (some type of sensor), just be sure that you plug the connector again if this hapens

https://www.fcpeuro.com/products/porsche-engine-crankcase-breather-hose-boxster-14743006001?utm_source=FCP%2BEuro%2BCustomers&utm_ campaign=0b9b152c3b-Porsche_Breather_Kits&utm_medium=email&utm_term=0_ 01ec419f56-0b9b152c3b-206933345

Update
 

Reattached the vent tube (by feel), reassembled everything. Same exact response. Running on 3 cylinders. Got my Durametric today. No codes. I do feel this is air/vacuum related at this point. But to really see the PCV valve, the airbox needs to come out, and to get to the other end, I need to get under that input manifold. So, the excitement has quelled. On to get things done.

So the injectors are pulsing, but they could be dirty. You could still have a leak somewhere. Hoping someone with Durametric value experience can help you use it.

Have you tried a new fuel filter? Just realized you have a 98

Fuel filter is brand new

Tada, I replaced my tube because it was creating a mess (I knew it was broken somewhere), and being an accordion type, unless you remove it, it could be difficult to inspect it for cracks...

I think I found a problem. It may not be a no run problem, but it is an obvious problem. Look at the AOS below. Sometimes I just miss the obvious. That cap on the AOS where the J tube should be was capped off with a carb cleaner cap. Underneath I found duct tape over the opening on the AOS. I found the exact same setup on the throttle body. So, it seems to me the PO tried to plug these off because the AOS has probably failed. So an AOS replacement along with all the breather and vacuum tubes is in order. Can this be the root of my problem?

The tape installed by PO:

Absolutely. Replace that along with the j tube. I'd be very surprised if that wasn't your issue. I'm pretty sure these cars can't run without a functioning air oil separator. If they could none of us would bother replacing ours. Your po is not very smart.

100% shure that this can cause the problem, because the engine gets false air. This will definetely cause a rough idle.

Regards, Markus

Did this resolve your issue?

Thanks for asking. I'm still working on it. I ordered the parts last weekend and received them yesterday. I knew the middle tube on the AOS was detached at the crankcase vent valve in front of cylinder 4. So before I started the whole AOS removal, I decided to reattach this hose. I got my hands in there from below the car. I lined the "quick connect" vacuum line up with the fitting on the valve. I pressed and pressed the hose. I could never get it to go on. I examined a normal fitting and the hose off the car on the new AOS and J tube. It looked like what I was doing should work. But I can never get the leverage necessary to completely get that locking ring over the fitting. The only way I can see to get the necessary leverage is to remove the air box, which looks worse to remove than the AOS. I don't know if dielectric grease or even oil would help this hose attach to the valve. But I lost a lot of skin off my knuckles last night (through nitrile gloves) squeezing my hand into that air box area just to grip a small bend of the breather hose.

Tada,

I would recommend to lube the o-rings on the accordion tube as these are easy to damage when you are pushing trying to secure the locking ring.

Also, examine closely the accordion hose as a crack can be difficult to see, yet will have a vacuum leak and make a mess if left unattended.

Good luck.

Lucked out big time. I went through the firewall and was able to pull the breather hose a little tighter on the valve. Then from below I was able to finally push it hard enough to snap it closed. Attached is a pic of the valve and breather hose taken from the firewall side. It's a PITA to reach. But it's done and no air box removal needed.

While I was under the car I undid the middle hose from the AOS, undid the bellows tube (PO had obviously replaced the AOS before - had a radiator hose clamp on it), and unbolted it from the bell housing with a 1/4 ratchet and 10 mm socket. That only took 15 minutes. So the old AOS is out. I did luck out with the radiator clamp. Now to enjoy an adult beverage and clean things up. I'll drop the new AOS in in the morning along with a j-tube and try to fire it up!

Thanks, Tom

Well, luck ran out. Got the AOS installed. Same symptoms persist. I can feel the crankcase getting ventilated, I removed the oil filler cap and could feel a slight vacuum. So I know I'm getting vacuum now. Here's a video of it running (if you call it that). I'm kind of running out of ideas. These are the same spark plugs that I have been using. They're getting spark but they were soaked in gasoline at one point. I may be down to injectors, but I'm having trouble believing that three are sticking on cylinders 4, 5, and 6.

Tom

http://youtu.be/hcf91h2wSSg

Thanks for the video. This doesn't sound like rough idle, that sounds like it's running only on 3 cylinders / one bank.

Can you rev it up? Or does it only run on idle like shown in the video and does it die if you press the throttle?

Did you check the coolant water for oil? Any cracks in the engine housing?

Do you have the possibility to do a compression test / or have you done a compression test on each cylinder?

Did you check if the injectors work correctly?

Have you tested the ignition coils? Are the coil packs OK or do some of them have cracks?

Regards, Markus

It is only running on cylinders 1, 2, and 3. The other bank is constantly flooded.

Can't rev it up. Dies if gas is given.

No cracks in the housing. Coolant and oil are clean. Oil is starting to smell like gas.

Have not done a compression test.

I checked all injectors with a noid light. Light is pulsing on all cylinders.

Coil packs have no cracks, ohmed out correctly and I have spark at each plug (grounded the case of each plug while attached to the coil pack and verified spark).

So I now have spark, injector pulses, and vacuum. I guess I should run a compression test. The only thing left is to get the injectors cleaned and flow matched.

Thanks for the suggestions.

Tom

Compression test is probably the way to go. Dang, I was really hoping we had you figured out with the AOS. Sounds like this thing was seriously neglected by the po.

I may try some new spark plugs. I changed these when I first got the Boxster. They are really fuel and carbon fouled (per bank). No miles on them, but it may be good to eliminate variables.

+1 on the compression test BEFORE you buy new plugs. Establish the unknown first then eliminate variables.

Is it possible to have the wires run to the wrong coils on a Boxster? I found that on a Ford Escape V6. Seeing how that AOS was rigged, I'd be looking over *everything* that could have been touched by the PO or his 'mechanic'.

Based on the AOS I'd say anything is possible. However it would take someone really skilled (sarcasm) to mess that up and it would be misfiring which by the video it isn't. Compression test would offer some clue to mechanical integrity.

I don't think the coil wires will reach to different cylinders.

tada - have you used a Durametric to check out possible problems? You are chasing your tail without some form of scanner to give you some clue as to what is going on.

If all 3 cylinders on one bank are failing to fire (I assume the offending header pipes 4,5 & 6 are still cold even after the engine has run on cylinders 1,2 & 3), then I think you have a deeper problem than an air/fuel/spark failure. I can understand losing one cylinder due to a fault, but not three - especially all on the same bank.
After a compression check (which is a must) plus a comprehensive Durametric analysis if possible, a more serious mechanical problem is in your future, like bent valves - which a compression test will show - or valve timing issues.
If you do complete a compression test, just make sure you remove all plugs first, remove the fuel pump fuse & make sure the throttle body is fully open (foot hard down on the accelerator pedal). Then start on the "good" side to get 3 x comparable results before going over to the problematic side.

Wow, what a struggle to find the problem. This will be interesting to find the cause.
The best clue is No CEL. There are only a few component faults that cause bad running but do NOT set a CEL after the problem is detected 3 times. That may be a good basis for a google search ?
I understand why you want to inspect the injectors but you my find them difficult to remove. Each injector has a tiny screen in it -they may be plugged?
Good luck and let us know your progress.

Tom - stupid question: is the CEL bulb working? Means - is the light of the CEL light ON if ignition is ON?

I would do a compression test first, because there is a whistling noise in the video that sounds like a bypass / not closed valves.

Regards, Markus

The CEL appears to work. It comes on when the key is in the ON position and when the engine finally stalls, but not when it is trying to run. I will run a compression test later today after I take care of some honey dews. I have a functioning Durametric Enthusiast that shows no codes being thrown. But if any of you good folks who are fluent in Durametric would direct me to what to look for on it, it would be appreciated. Thanks again, Tom

Compression test results
 

It's amazing to me how many chores we have to do to gain access to our Boxsters. Anyway, here are the numbers for the compression test:
Cyl 1 - 133 psi
Cyl 2 - 140
Cyl 3 - 133
Cyl 4 - 121
Cyl 5 - 126
Cyl 6 - 122
WOT, performed at room temp

Now I can see the second bank is lower, but it should not just flood. The car has 96000 miles, had 7 owners, and they probably drove the piss out of it. I'm still suspect of the Bosch Platinum +4 spark plugs. They've been in since troubleshooting began and have been flooded several times. I have a new set of Bosch 7402s that look like OEM. I'm tempted to try them.

I don't know enough about what those numbers mean, but what's another new set of plugs cost? You may as well eliminate them if others state your compression numbers look normal.

I think the numbers mean it's ok. The highest and lowest value are within 15 percent of each other. So for now, I'm going to rule out a bent valve (that would be a crap your pants moment).

I have the new plugs - Bosch 7402 (FR7LDC+), copper with just two electrodes that I will install tonight. Maybe with a little luck it will fire up. The Durametric is still showing no codes being thrown.

I'm not sure you're ok. Hope you are but something I've been thinking for a while on your car is this, AOS was taped up and removed for some reason. If liquid oil was dumped from AOS into the 4,5,6 bank it would bend rods, not valves. Those compression numbers are pretty low, I would think they should be closer to 145 psi. JFP would certainly have the best info here. Good Luck.