FAQ: Boost Bypass Valve/Boost Control Solenoid Questions (No Boost)

J. Chris Davis wrote:

Ok, thanks. I'm gonna try that test when I get home tonight.

So, what's the verdict.? Do you need a new one or not.???

Eldo wrote:

No, he posted a non-Riv photo... (Bad boy! )

Notice the 'wrong' parts mounted to the passenger-side strut-tower?

OMG I can't believe I missed that. Fuse Box, engine mounts, the brace from the core to strut tower, the coolant reservoir.....I deserve that stick

Aaron, I'll apologize in advance: I'm sure there's a better place to put this, especially after our latest PM's, but I just can't decide today...

Anyway, here is my latest experience for folks who need a new BBV BCS - can't have enough three-letter-acronyms can we?


While GMPartsDirect.com has currently suspended their online catalog because of parts that were
listed but obsolete, if you enter 1997244 into the part number field, you should find this valve...
I've enclosed 2 photos to show both the unit itself, and yet another term that GM used to describe it,
besides the ones that AA already listed in his parts thread.
.

Here is the GM parts tag, showing the number and the description as a "Supercharger Wastegate Valve":

.

And here is the actual part called an "Evap Solenoid", including the correct S2 bracket and a fresh breather-filter:

.

For once, the Delco number and the GM number are the same, except for the leading zero, and the total cost with shipping & handling was $38...

Abaddon wrote:

Eldo wrote:

No, he posted a non-Riv photo... (Bad boy! )

Notice the 'wrong' parts mounted to the passenger-side strut-tower?

OMG I can't believe I missed that. Fuse Box, engine mounts, the brace from the core to strut tower, the coolant reservoir.....I deserve that stick

Actually, the 'stick' was for his posting of the non-Riv...
If I was going to criticize you, I would have used a or a

(I guess it's a moot point now... )

Ya sorry for the non Riv pic. It was what I had at the moment. I do need a new one. It's leaking a bunch of air out of the bottom of it. Found one on ZZPerformance for 40 bucks.

J. Chris Davis wrote:

I do need a new one. It's leaking a bunch of air out of the bottom of it. Found one on ZZPerformance for 40 bucks.

Does the one from ZZP fit other cars.?
Does it have the vacuum ports facing in the correct position.?
Etc, Etc............

As far as I know it's the right one. I'll find out for sure when I get it.

Perhaps the vacuum ports don't interfere with anything, because they're selling the same part for Series II and Series III... S3 has a Gen V, right?

Well I'm at work and got the valve in the mail here. It looks like the correct one. It is missing the little arm with the bolt threads on it for that one part to mount to. I'll find out more when I get home tonight to work on the car.

Ok the ZZP Bypass Valve is not the right one. The top vacuum port is in the wrong place and it is missing the part of the bracket for a vacuum solonoid.

bummer. that # doesnt show anymore

I got a CEL this afternoon. Car was running strong this morning but later in the day it felt like it lost some TQ and HP.
Finally the CEL came on and i figured it would lead to something useful and explain the power loss.
P1655 and P1441 which from what i have been reading are both EVAP codes.
I pulled the charcoal canister from the rear driver fender and it feels pretty heavy. i turn it over and a orangeish oil substance drips out from where the vac line goes. Smells like fuel but feels like oil.
I am going to pull the line off the solenoid/purge valve and try to blow air through it to see if the line is clogged because im guessing this isnt normal.

Any other suggestions?

TIA
Matthew

Looks like your covering all the bases. The only thing I can thing of is if its the purge solenoid valve itself. Thats what it was when I got that code. By the way, was it tuff getting those plastic fuel lines off the canister. I am afraid to remove mine as they look so brittle. How did you do it?

my lines were in pretty good condition. they dont push on very far and i left them in the top of the canister, just removed the bottom and the inside.

Don't have much time, I'll elaborate later.......replace your Purge Solenoid.

Abaddon wrote:

Don't have much time, I'll elaborate later.......replace your Purge Solenoid.

Abaddon to the rescue! Up Up and Away!

found out why it feels so sluggish now.
i am only making 4.3lbs of boost! WTF?
are these problems related?
i cleared the evap code and its hasnt come back on.

according to another thread "QDM 2 is the BCS/Evap/TCC" so do i need a new pcm? or just a bcs and evap?

On your '96....

P1655 EVAP Purge Control Circuit
P1441 EVAP System Flow during non-purge

When P1655 is accompanied with P1441, 90% of the time the Purge valve is stuck open and allowing fuel vapors to just flow into the T/B and the S/C when not commanded to do so.

OK thanks Scott. I will swap out my BCS and purge vlave this weekend with some working solenoids from a friends regal.

So are my 2 issues non related? or did the failing purge solenoid cause the BCS to fail due to carbon and fuel entering the TB?

Np.....

I don't think the problems are related, just a mere coincidence. Your Purge Solenoid would have to be letting the vapors by for a long time for that to happen.....but then again, fuel is an excellent cleaner
Even If that were the case, the P1441 would've set long ago. Purge valves can get stuck, and still work electrically (GM 4.8L happens ALL the time), but will set P1441 (in the Rivs case) as soon as the PCM runs it's EVAP test. I would think all the carbon/soot buildup on the BCS is more oil/blowby related from the PCV system than anything else. Do you have another breather built into the oil cap? I drilled a hole in mine and glued a Crankcase Filter inside of it just so the PCV can keep up with all the boost.....

yes i am running a breather. and after the I/C install my PCV valve is doing nothing...still need to pull it out i guess.

Mr.Riviera wrote:

yes i am running a breather. and after the I/C install my PCV valve is doing nothing...still need to pull it out i guess.

ah yes.....I can never remember what everyone has done to their ride

So i swapped my BCS with one from another riv and i am still only hitting a max of 4.5lbs boost. WTF!?!

What else could cause a serious boost loss? i dont have a vac leak either.
EVAP codes have to be related somehow.

I am not having any TCC problems but i find it weird that the EVAP and BCS are both operated off the same quad driver.
Any way to replace that or test it?

anyone?

Is the quad driver part of the PCM or something separate i can check?
All the fuses un the I/P and under the seat check out with an ohm meter.