98 v70 NA P0455 - my most loyal friend

[abscate]

Measure resistance between the ground wire and ground to test it. Make sure you get the right wire or disconnect the battery first .

[98v70dad]

Measure resistance between the ground wire and ground to test it. Make sure you get the right wire or disconnect the battery first .

I'll check it as soon as I can. Tried it tonight and I think my multimeter is done. It worked yesterday although I had to turn it on and off a few times to get the display to light up. Today I don't get a display when I turn it on. Batteries are new. I bought it at radio shack 26 years ago. Its the only thing I've ever bought there that lasted more than a year. Although, I've probably used it less than 30 times.

I thought it might be a blown fuse so I slipped in a little piece of 1/4" copper tubing in the fuse holder just to see if the display would light up or if I could get a continuity beep....nothing. So, I'll need to get a new multimeter before I can measure the resistance. Another radio shack purchase in the trash.

Are there any good values out there for someone who doesn't use one that often?

[abscate]

harbor freight for a cheapie. I go into the lab and requisition a Fluke traceable to NIST

[sleddriver]

An interesting thing I discovered about the PURGE valve (which on my car, is attached to the radiator) is that it is pulsed on/off/on/off continuously with the engine running, even at idle. I tested it with both a vacuum and small pressure in both the static OFF and ON states. But when I began pulsing it back & forth at about 1 pulse/sec., it would FAIL and leak. The PURGE valve goes through 1000's upon 1000's of duty cycles...closed/open/closed/open continuously. In comparison, the SHUT-OFF valve doesn't. It isn't pulsed at all. It's either open or closed.

Finally, the pressures and vacuum sensed are very, very tiny. Not anywhere near an inch of water, much less an inch of mercury. The vacuum on my tank while running the diagnostic test was only -1200 Pascals. That's it. 1 psi = 6895 Pascals! So -1200 Pascals = - 0.174psi. That's why the emissions systems on these cars are so damn finicky.

I discovered I was using way too much pressure and vacuum to "test" these valves. The trick is using something much smaller, like an aquarium pump. And to build yourself a DIY smoker. Wish I had years ago. I'd of been rid of the dreaded P0455 years eariler!

[cn90]

Interesting re Purge Valve function.

I am waiting for the weather to get warmer so I can test the Purge Valve Connector for signal during engine operation.
I will report back later.

[98v70dad]

harbor freight for a cheapie. I go into the lab and requisition a Fluke traceable to NIST

Yep. I used to work in the materials lab at Georgia Tech Research Institute (GTRI) and you can't beat a Fluke when it comes to quality. You've bounded the solution by suggesting the $5.00 HF "tool" on the other end of the scale. I'd be afraid to hold that in my hand and check voltages on anything more than a flashlight battery. I would serve for my purpose this time but I can't see myself buying one.

Seriously, I was looking at the Home Depot site and they have several Klein models that look decent. I like the auto-ranging Klein that costs about $70.00, although that's a bit much for a tool I didn't know I needed two days ago.

Lowes has a couple of Southwire multi-meters that look decent also, but Lowe's is a good ways out of the way for me and I'm cooking dinner tonight.

[98v70dad]

An interesting thing I discovered about the PURGE valve (which on my car, is attached to the radiator) is that it is pulsed on/off/on/off continuously with the engine running, even at idle. I tested it with both a vacuum and small pressure in both the static OFF and ON states. But when I began pulsing it back & forth at about 1 pulse/sec., it would FAIL and leak. The PURGE valve goes through 1000's upon 1000's of duty cycles...closed/open/closed/open continuously. In comparison, the SHUT-OFF valve doesn't. It isn't pulsed at all. It's either open or closed.

Finally, the pressures and vacuum sensed are very, very tiny. Not anywhere near an inch of water, much less an inch of mercury. The vacuum on my tank while running the diagnostic test was only -1200 Pascals. That's it. 1 psi = 6895 Pascals! So -1200 Pascals = - 0.174psi. That's why the emissions systems on these cars are so damn finicky.

I discovered I was using way too much pressure and vacuum to "test" these valves. The trick is using something much smaller, like an aquarium pump. And to build yourself a DIY smoker. Wish I had years ago. I'd of been rid of the dreaded P0455 years eariler!

Good information. Hopefully it will help someone. It doesn't help in my case. Until I discovered what seems like a degraded ground wire, I had suspected all the usual things and replaced them all. I have all new rubber front to back on the system that holds the vacuum and a new OEM purge valve and a new OEM shut off valve. All of thios didn't cost that much other than it has been very costly in time spent.

If chasing down the seemingly bad wire doesn't help I am going to make a DIY smoker and I, too, plan to use an aquarium air pump to run it. I've got some good plans for a smoker and already starting buying parts for it when I discovered the possibly bad wire. I don't feel comfortable with a compressor even if it regulated because of the potential to do damage.

[sleddriver]

There are lots of DIY smoker videos to watch. Mine was very simple, making use of what I had on hand. I started with a new metal gallon paint can. Poked a hole in the side near the bottom, the size of a skinny piece of silicone vac tube, which was connected to a large aquarium pump I already had. In the lid, I used a Schrader valve with a nut & washer I also had, with the valve removed. This isn't necessary to make it work though, just another hole in the lid the size of your vac tubing.

To produce smoke, I used firework punks, which I seemed to have plenty of. I stuck a large mound of heavy putty in the bottom, but 2 or 3 punks to fit, lit them, turned on the aquarium pump and seated the lid. Pretty low flow, but good enough. When I ran out of punks, I used some brick incense I also had on hand. So when you can't SEE the smoke, you can use your nose to SNIFF for it. You can add a couple of rocks or large sockets in the bottom as well to stabilize the paint can and keep it upright.

I plugged it into the line where the PURGE valve is on the radiator, leading back to the CharCan, which is in the rear on my 98 V70 T5. It'll take awhile to build pressure. You can remove the gas cap until you smell or see smoke, the replace. My paint can lid had a small crease in the top which proved helpful: As pressure bilt, then peaked, the crease would finally POP, thus providing an audible indicator the system under test was pressurized. When pressure was released, it would POP again. Note it's sometimes hard to see the smoke, particularly in the sunlight!

I also used the same set-up to find several small engine vacuum leaks, split elbows, etc. I wasn't aware of. The result was an noticeable improvement in gas mileage AND boost performance as I also discovered some of the boost/vacuum check valves were Tango Uniform (i.e. leaking). Fixing these REALLY improved the get-up-and-go. I also did the SAS delete, mentioned on MVS, and passed inspection no worries. So glad to be rid of that #$%^! system.

I feel your pain re: P0455. Been there. Suffered That. You can read my ordeal in the earlier links. I found a good diagram and detailed explanation of how it all works. I was contemplating dropping the tank, but with it full of smoke and pressurized, I could neither see no smell any smoke with all the back floor plates removed. Nothing. Thus, I ruled it out. Good luck to you! May the smoke be with you...always!

[cn90]

Curious re dry ice (CO2).
Has anyone used dry ice? Basically drop a cube inside the gas tank and let the CO2 smoke build up and track for any leak.
Just curious.

[erikv11]

"CO2 smoke" is not CO2 at all, it is water vapor.

When dry ice melts and the CO2 goes to gas phase, moisture in the air condenses due to the low temperature of the CO2 gas, to make "cold steam." That's what you see, the water droplets. Fog.

I don't think a piece of dry ice in the tank will do what you have in mind, unless there is a lot of moisture in the lines (and you don't really want that). And "gasoline steam" wafting about sounds risky.