JFP in PA

Have you tested the fuel pressure and delivery rates?  Problems in that area will make the car run like crap and not throw codes.................

You haven't mentioned two items: removing and testing the valve itself and testing the triggering wire back to the DME pin for continuity.

Slot #1 in the trunk, but if you have power at the valve harness connector, it should be working.

According to the wiring diagram in the OBD II manual for your car, the valve should have two wires, #2 that receives a power signal from the DME relay terminal 87; and the #1 wire that runs to the DME terminal #7 (the DME supplies the valve's ground when it needs to run).  I do not have the color codes for those two wires.

Have you checked the valve to see if it functions?  Unplug the harness connector at the valve, there should be a 22-26 ohm between pins 1 and 2 on the valve, and you should see battery voltage on the wiring harness connector pin #1.

The code read out is as stated: "Open circuit, check valve voltage supply, check valve for function, check trigger wire for continuity"

9 minutes ago, ziggyrama said:

yes, makes sense. Is there is a constant 12v to the valve once the car is on? I also read that there may be a clogged line to check for as well.

That is possible, but would throw a different code if it was  Your code is an electrical issue.

11 minutes ago, ziggyrama said:

will do, thank you. I will disassemble the wheel well again and take a look.

When you do, check that the valve has electrical power before doing anything.  If there is something wring with the wiring, changing the valve will get you nothing.

14 hours ago, ziggyrama said:

Thank you JFP! This is the valve located near the throttle body under the intake? Does this part generally fail and need to be replaced, or do the connections sometimes just need to be fixed? I noticed it is $350 on Pelican so wondering if I should plan on purchasing it. 

No, it is located at the EVAP system cannister in the wheel well (item #6):

And don't buy from pelican, use board sponsor Sunset Porsche

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P0306 is a misfire on cylinder #6

P0447 indicates an open circuit (disconnected electrically) on the EVAP cannister shut off valve.  Possible wiring issue or valve itself.

P1318 also indicates a misfire on cylinder #6

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Iam not aware of any such item.

There are multiple aftermarket top suppliers that make glass window replacement tops that fit the earlier cars, but they have a smaller rear window because of the differences in the mechanical mechanisms. 

If the top has a glass rear window, the answer is no; if it is plastic, the answer is yes.  The glass window tops used a mechanical top system that has one extra metsl bow to accommodate the glass window.

It really isn't necessary, but you can do it using a product called Fogging Oil:

Time to run a parasitic drain test, which has been written up multiple times, but there are also a ton of online videos :

.  Basically, after the car has been sitting for about an hour or so, there should be a 45 - 60 milliamp current drain on the battery from necessary things like the clock and the alarm system; any higher than that and you have a parasitic drain on one or more of the electrical circuits.

1 hour ago, scanner-1 said:

Many thanks Loren. That diagram was exactly what I needed. The valve in question is hiding in plain sight on the front of the engine, well obscured by the serpentine belt and a host of pulleys and not easily accessible due to radiator, etc.. For unknown reasons, the wiring was severed about four inches from the valve. The wiring harness gave me just enough play to back it out and do a soldering job in the left front wheel well. Reconnected and the code is now clear.

My next question is, what is your source for the diagram? Do you have a repair manual recommendation? Locating that particular diagram would have saved me hours of fruitless internet research--Thanks again!

Loren showed you a section of the exploded parts diagram for the vehicle, which you can find on multiple public websites such as board sponsor Sunset Porsche.

19 minutes ago, alex222 said:

You right. 

 

I am having the #26 instead of #24 though - I have the Nav unit. So the question remains of where the #27 Control Unit is located at? 

Passengers side footwell.

According to Porsche, item #24 in the pillar is the "antenna booster", while the item you posted the photos of is item #27 is the "Antenna Diversity Control Unit" for the PCM navigation

Ever think it could be the ignition switch?

The antenna amplifier is located on the right A-pillar, behind the trim which is easy to remove

As the codes seem random, I would start by looking at the fuel trims and MAF signals.

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Without the actual codes the car is throwing, anything would be a guess.

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Or whomever did the replacement did not torque the new units with the car sitting on its wheels.

35 minutes ago, 1947verns said:

Prior to pulling the plugs the engine was started and ran with no issues. The transmission was in neutral and the clutch was depressed when trying to turn the crankshaft pulley.

When looking at the lower pulley on the front of the engine, which direction did you attempt to turn it, clockwise or counterclockwise?

1 hour ago, 1947verns said:

I want to do a leakdown test on my 1998 Boxster, I need to rotate the crankshaft pulley to position the cylinders to top dead center, but the crankshaft pulley does not turn when a socket wrench is applied to the crankshaft pulley. What is needed to free up the crankshaft pulley? The engine is in the car. Please advise. Thanks.

 

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You have a potentially major issue here; if the crank cannot be turned by hand with a wrench, either the engine is seized, or something is mechanically jamming the rotating assembly (are you sure the trans is out of gear?).  If the trans was in neutral, you need to do further diagnostics into why it won't rotate, which could get into serious disassembly, including dropping the engine out.  In almost any permutation as to why this is happening, you are looking at some serious $, and trying to force it to rotate will only worsen the situation.

Good luck.

Sometimes you simply have to go with the factory system due to what Porsche sees as "proprietary".  Glad you got it sorted 👍