ziggyrama

On 4/18/2023 at 9:48 AM, JFP in PA said:

Both problems point to a dead or partially dead hole, question is why?  Pull the plug and look at it, if it is black and sooty, it isn't firing consistently.  Question then is why, the EVAP system is incapable of killing a single cylinder, so it is something closer to that cylinder (coil pack, plug, injector, harness and connections, etc.).

I pulled the coil pack for cylinder 6 and 5; both test the same and the spark plugs look good. There doesn't appear to be any physical issues with the harness or connections that I can see. I've read on some other forums about issues regarding the ECU and wondering if there is any other tests I can preform? With the other weird electrical issues that occurred at the same time, is this a real possibility? Thanks

20 minutes ago, JFP in PA said:

In order to do any tests on this valve, you need to get access to it, so by that point you might as well pull it for bench testing. but that valve malfunctioning should not cause a single cylinder misfire on cylinder #6.  Are you completely sure you don't have a coil/plug/injector issue on that hole?

actually, I am not sure; the car drove perfectly fine one minute, and then literally threw all these codes at once on the next drive. Would it be more beneficial at this point to check the coils/plugs/injectors rather than chasing the EVAP issue? My only insight is that the car idles rough due to the misfire and has a very strong gas smell.

After some more troubleshooting, I decided to bypass the factory wire harness and do some more testing. The valve now has a low voltage (around 7v) and it very similar to what the author is describing in this old post. The car no longer has the original P0447 but is still misfiring with a P0306/P1318 error. In the post, the author had replaced the fuel line vent valve which was also showing a low voltage. Is there any way to test this valve without removing it or do you have any other suggestions for what may be the issue now? Thank you

On 4/14/2023 at 4:09 PM, ziggyrama said:

After some testing, there doesn’t appear to be any continuity between pin 1 on the valve and pin 7 at the DME. Actually there is a very low resistance of about 70 ohms between pin 1 and ground. 

I've traced the wire through a loom that travels down the left side of the car and up behind the dashboard; there is continuity from PIN 7 to that spot under the dash, but doesn't seem to be from there to the valve. Without any way to really trace it behind the dash, I don't know where the short or cut may be. Any thoughts? Are there any plugs between there and the valve that you are aware of? Thank you

After some testing, there doesn’t appear to be any continuity between pin 1 on the valve and pin 7 at the DME. Actually there is a very low resistance of about 70 ohms between pin 1 and ground. 

10 minutes ago, JFP in PA said:

But did you test the wires between the sensor and the DME for continuity or shorts to ground?  Your code is for an open circuit, indication of a wiring discontinuity. 

I will re-test continuity between the valve wire 1 and the DME; if there is voltage at the valve, wouldn’t that indicate it should be working ok?

On 3/2/2023 at 1:58 PM, JFP in PA said:

The second, or trigger wire, runs from pin #1 on the valve to terminal pin #7 at the DME.

Thanks for the advice.
 

Now that the weather has cleared, I was able to resume testing and the voltages test fine. I’m at a loss now as to what to check for next. 

Thanks for the clarification. Do you have any information on the DME and what pin that wire is on?

I tested the valve and it operates manually when I connect it to 12v. I will test the continuity between the relay and the trigger wire. Thank you. 

Thanks. I was able to remove the relay and test that it is working properly so now I’m not certain now what the issue is. 

The valve tests at about 24 ohms and has constant 12v on pin 1 when the ignition is on. Could you point me in the right direction to find the relay so I can test it? 

After some testing, there is 12v between the ground wire that clamps to the fuel line and the blue/red wire on the valve.  The yellow wire doesn’t appear to have anything present on it. Does that sound correct?

Update: removed the canister and valve and can confirm valve opens manually when I apply 12v directly 

6 minutes ago, JFP in PA said:

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

Ok, didn’t realize it was specific to an electrical issue. Are there any fuses or other issues I should check first or is it part of another system? We did have new stereo equipment installed, now I’m wondering if something happened. 

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.

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

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. 

Greetings, my wife recently purchased a 1998 Boxter with 30k miles from the original owner. A month after we got it, it began having some issues including idling rough, showing multiple codes including a vacuum leak and an occasional misfire. After some research, I replaced the gas cap, replaced the fuel tank vent valve, and cleaned the MAF sensor, but it is still not running properly. I've read more that perhaps the issue is due to a bad resonance flap actuator or vapor canister purge solenoid? I don't have a lot of experience with this car, so I feel like I am just chasing the issue - any advice would be appreciated. Thanks