EVAP purge valve facts about how it fails. FYI only.

[Red-Arrow]

Well I finally discovered the mysterious fault with my engine check light and the main reason why the previous owner sold it and how his so called Volvo specialist could not cure the turbo brick.

I was at my wits end replacing all the hoses, EVAP canister and double triple checking parts the 315 code would come back on after ever 17 minutes of idle. This went on for months. I pressure tested everything and replaced the fuel cap and nothing helped.

I used a brand knew EVAP purge valve but it was not the correct part but I figured they all do the same job. Wrong

I ended up buying a similar Bosch purge valve but it was from an older Volvo, The connectors was designed not to fit the 95 850 Turbo so I just cut the offending plastic off and it clicked right in and the engine check light has been off for 4 weeks after 500 miles.

I did this after I cut the original purge valve open after reading a thread about them not sealing correctly with age and I thought I could service it. Wrong again

Its not the seals that fail but the copper track that conducts the electrical current, with age they snap and crack when this happens it can no longer fully energize the copper coil, the result is a weak seal. Engine vacuum can still pull air into the engine throwing the fault code and messing with fuel consumption.

So if your get this 315 code and you have replaced all the hoses to the gas tank and the EVAP canister and you still have the 315 code, I would put all my chips on it being the purge valve.

[jreed]

Very nice sharp photos! Thank you for posting this tear-down!

[V850B5254T]

Hi All,
Living in Europe (Denmark), it is somewhat depressing to tell North Americans that this renowned German manufacturer of auto parts often delivers products with design flaws.
The problem shown in this entry is in my opinion caused by metal fatigue and is something that should be embarrassing to Bosch.
They have designed and produced a number of automotive relays (e.g. the fuel pump relay used in 850) that has a build-in aging factor. It is simple flaws, - something I learned about when attending my electronic engineering study in the 70’ties.

And there are a lot more unnecessary design flaws floating around in the cars we are driving, whether it is Volvo or other marks.

Maybe we (members of automotive interest groups like Matt’s) should join force and contact the automotive industry with our experience and listen to their answer......
Alone we can do nothing.

Well, - it is just a dream, but a nice one.

oakey

[Red-Arrow]

it is somewhat depressing to tell North Americans that this renowned German manufacturer of auto parts often delivers products with design flaws.
The problem shown in this entry is in my opinion caused by metal fatigue and is something that should be embarrassing to Bosch.

I firmly believe this is designed obsolescence, designed to fail after a certain number of operations. I had to melt,cut and damage the purge valve to access the working parts coil and plunger. Should I believe Bosch are so foolish as to not realise they could used a screw cap with an o-ring seal so it could be serviced for a few Euros/Dollars.

They have designed and produced a number of automotive relays (e.g. the fuel pump relay used in 850) that has a build-in aging factor. It is simple flaws, - something I learned about when attending my electronic engineering study in the 70’ties.

Your right but Work hardening is unavoidable with copper but Bosch know this as again.

And there are a lot more unnecessary design flaws floating around in the cars we are driving, whether it is Volvo or other marks.

Maybe we (members of automotive interest groups like Matt’s) should join force and contact the automotive industry with our experience and listen to their answer......
Alone we can do nothing.

Well, - it is just a dream, but a nice one.

That would be something but in that philosophy companies would accept customer feedback and so by now we would have cars so robust and long lived, Volvo would not be selling much else. Corporations who's goal is to make profit above all else, well they don't share your good nature and perfectionism.

oakey[/quote]

[thecheat]

Let us not forget that this is a part in an up to 17 year old car!

I need to revise my guide on the Volvo EPV as I discovered that while the valve is identical to the BMW valve it is based off of, the Volvo valve is normally closed while the BMW valve is normally open!

I should think that the diagnostic vacuum test should still apply but the results would be reversed... applying current to break vacuum instead of applying current to close the seal.

[nedro018]

I'm really glad I stumbled to this post.

The wife forced me to drive our (uhmm...her) 95 850 NA until I fixed her intermittent no start after the car would successfully startup each morning. It ALWAYS started in the a.m. but might/might not 4 hours later. I R2 ECP sensor, FP relay, and fuel filter, no help. It turned out to be the crankshaft position sensor.

Well after I fixed that, I started fixing all the little stuff. This car has had a 315 EVAP code for years and years. I replaced several gas caps, some Volvo, some not, no help. But I thought, "who gives a crap about EVAP? codes? So a little gas escapes in the air. Who cares?"

But now that I was bent on fixing the car completely, I had to finally deal with this POS code. Now, there was a persistent gas odor in the cabin after some driving, and also in the closed garage first thing in a.m. That turned out to be the cracked rollover valve hoses by the fuel filter so I replaced them. I thought this would also fix the 315 code as well. It didn't.

So I changed the charcoal canister with a junkyard model, when I did I also blew air (with my mouth) thru both canister lines (to tank and to valve) and they both seemed to "hold" (the valve side didnt budge, and after a big puff to the tank side, all the air seemed to return back to me and I didn't hear any leaks downstream). I also replaced the 10" black vacuum line going from the EVAP valve to the manifold. No help, still getting 315 hits.

So I went back the the junkyard and pulled from a 94 850 NA (1 yr older than mine) an EVAP valve and it was exactly the part number above ending in 302. but it didn't fit into my connector, also, when i saw that my part number ended in 300 NOT 302, I didn't swap it out and put it back in "benchstock". My logic in doing this was, "What's the chance of a valve failing vs. a leak somewhere? Not much...you have a leak"

Well after reading this post, I just retrieved it and filed down the offending keyways so it would mate to my connector. We'll see what happens, I will update here after I drive for a bit.

If all this pans out the only task left is to condition the leather seats! Sweet.

Our 95 only has 147K on it. From from what I've seen in the 3 junkyard 850's (165K, 187K, 247K), this is pretty low mileage and it would appear this car has a lot of life left in this downed economy. Given the fact that I have an extensive bench stock of sensors and electrical cabin switches/relays for replacement and troubleshooting, I think we'll hold on to this car.

Will get back on result of above part change. Thanks all.

ned

[byeboy]

I'm really glad I stumbled to this post.

The wife forced me to drive our (uhmm...her) 95 850 NA until I fixed her intermittent no start after the car would successfully startup each morning. It ALWAYS started in the a.m. but might/might not 4 hours later. I R2 ECP sensor, FP relay, and fuel filter, no help. It turned out to be the crankshaft position sensor.

Well after I fixed that, I started fixing all the little stuff. This car has had a 315 EVAP code for years and years. I replaced several gas caps, some Volvo, some not, no help. But I thought, "who gives a crap about EVAP? codes? So a little gas escapes in the air. Who cares?"

But now that I was bent on fixing the car completely, I had to finally deal with this POS code. Now, there was a persistent gas odor in the cabin after some driving, and also in the closed garage first thing in a.m. That turned out to be the cracked rollover valve hoses by the fuel filter so I replaced them. I thought this would also fix the 315 code as well. It didn't.

So I changed the charcoal canister with a junkyard model, when I did I also blew air (with my mouth) thru both canister lines (to tank and to valve) and they both seemed to "hold" (the valve side didnt budge, and after a big puff to the tank side, all the air seemed to return back to me and I didn't hear any leaks downstream). I also replaced the 10" black vacuum line going from the EVAP valve to the manifold. No help, still getting 315 hits.

So I went back the the junkyard and pulled from a 94 850 NA (1 yr older than mine) an EVAP valve and it was exactly the part number above ending in 302. but it didn't fit into my connector, also, when i saw that my part number ended in 300 NOT 302, I didn't swap it out and put it back in "benchstock". My logic in doing this was, "What's the chance of a valve failing vs. a leak somewhere? Not much...you have a leak"

Well after reading this post, I just retrieved it and filed down the offending keyways so it would mate to my connector. We'll see what happens, I will update here after I drive for a bit.

If all this pans out the only task left is to condition the leather seats! Sweet.

Our 95 only has 147K on it. From from what I've seen in the 3 junkyard 850's (165K, 187K, 247K), this is pretty low mileage and it would appear this car has a lot of life left in this downed economy. Given the fact that I have an extensive bench stock of sensors and electrical cabin switches/relays for replacement and troubleshooting, I think we'll hold on to this car.

Will get back on result of above part change. Thanks all.

ned

Update??