BCS?

[Mike 72]

I have a 1992 SSEi that I think, from reading here and getting a code 56, has a problem with the BCS.
The threads I´ve read here regarding a code 56 is that when driving and leting the gaspedal up the Service Engine Soon lamp lights up and then it goes away a couple of seconds after I hit the gas again.
Also after getting the light the first time after start I only get about 5psi of boost at wot.

Can someone tell me what part I should buy, is it the part that goes under the name by-pass valve in different GM parts sites? (about $20-$25)

Also I would like to know if a BCA+BCS from a -96 SSEi fits a -92 SSEi?
I see that they have them listed 92-95 and 96-99, what´s the difference?
I found used BCS+BCA from a 96, is it possible to make them fit a 92?

I need to order online as I´m from Sweden and those parts have never been in store here.
There are not many newer Bonnevilles at all over here...

/Mike

[J Wikoff]

Also I would like to know if a BCA+BCS from a -96 SSEi fits a -92 SSEi?

Nope.

I see that they have them listed 92-95 and 96-99, what´s the difference?

Different construction.

I found used BCS+BCA from a 96, is it possible to make them fit a 92?

Nope.

Looking at the code list just now, your code 56 doesn't really indicate the boost control solenoid, a code 57 would.

http://www.pontiacbonnevilleclub.com/fo ... =51&t=1626

What problem is your car having? Your check engine light behaves more like an EGR fault, in my opinion.

[Mike 72]

Thanks alot, now I know that I need to order the parts listed for 92-95.

My problem is that I get bad throttle respons and not full boost.
Also as I stated in my first post, I´ve read other posts here in this forum were they solved the exact same problem as I´m having by changing the BCS.

/Mike

[J Wikoff]

You can test if the BCS is dumping boost by pulling the vacuum line off the bottom of the BCA (it's a little elbow, runs right into the BCS) and take it for a spin. Does your boost go up? You should see 8-9 PSI indicated on the boost gauge (55 - 68 kPa if yours is metric)

If your boost stays low, I'd look/listen for a vacuum leak in the BCA or cracked vacuum lines. Or maybe the BCA can't fully extend for some reason. This would not cause a light at all, though. So the 56 would be unrelated if it were the case.

[Mike 72]

I´ll try that tomorrow as it´s getting late and dark here now, it´s 8.00 PM.
It´s showing PSI, car is imported from the US.

/Mike

[J Wikoff]

Actually, thinking about it, a vacuum leak in or near the BCA would cause higher than normal PSI at idle, not low boost.

[Mike 72]

My bad, I´m getting a lower boost than normal when driving at 45-50mph and making wot.

/Mike

[J Wikoff]

I was correcting my own thought about a vacuum leak causing low boost.

[Mike 72]

I realized that after I posted.
Added information by me that it´s under wot I recognize lower boost and not the performance I´m used to.

/Mike

[J Wikoff]

Ok. One thing to check as well, if you pull the vacuum line off the top of the BCA at idle, does the "foot" on the lever below rest on the stop on the base of the supercharger?

[Mike 72]

I did run out of time checking the things I got tips of but will do it this weekend.
Just some more questions
How do I check my egr valve?
How do I clean the egr valve and do I need a new gasket if I unscrew it?

I also noticed that the car seems to behave as it should as long as it´s cold.
The SES light only lights up when the engine is hot and I lift the foot of the gaspedal and/or gentle brakes.

/Mike

[J Wikoff]

You can check the EGR by unhooking the wiring harness from it. The clip is a little tricky. You have to get the green tab out first. Then see if your SES light behavior changes. If not, you may need a new EGR or to clean it.

You can clean it by spraying its shafts with TB cleaner from the outside and taking a toothbrush to it. But it would probably be most helpful to remove it and spray it on the inside. You *might not need a new gasket. I've done that with the original gasket, but soot tends to build up around it if you don't put a new one in. With a new gasket, I've had the EGR off a couple times and reused it without any apparent effect.

If I remember after work, I'll look in my service manual for diagnosis of code 56.

[Mike 72]

Will try to clean it tomorrow.
I saw some bubbles coming out at the base of the egr when I looked at it last weekend, is that right?

Really nice if you can check the diagnosis of the code 56 for me.

/Mike

[J Wikoff]

Bubbles? Where? There shouldn't be any bubbles.

[Mike 72]

I saw bubbles at the base of the egr when revving the engine.
I thought it looked strange, will hace to look at that further.

/Mike

[J Wikoff]

Had you sprayed water in the area? I don't understand what the bubbles are made of.

[Mike 72]

No I didn´t spray anything.
I was rather wet outside though but that wouldn´t cause it I think, engine was at working temperature.

/Mike

[J Wikoff]

Looking at my FSM... Short of the BCS and/or the vacuum line to it and then unhooking the EGR and looking for behavior change in the boost and SES light, you'll have to probe the PCM harness to narrow the problem down to a single cirquit between the BCS, EGR, TCC solenoid, or shift solenoids.

To probe the PCM:

KEY OFF
DISCONNECT GREEN PCM CONNECTOR
KEY ON, ENGINE OFF
MULTIMETER SET TO 2 AMP SCALE
PROBE PCM HARNESS TERMINALS
-RED LEAD (+) TO PCM HARNESS
-BLACK LEAD (-) TO GROUND
EACH TERMINAL SHOULD MEASURE BETWEEN .4 AMP AND 1 AMP

PROBE THESE:

C9 BCS
C8 EGR SOLENOID 3
C10 EGR SOLENOID 2
C15 TCC PWM SOLENOID
D16 SHIFT SOLENOID A
D15 SHIFT SOLENOID B

[Mike 72]

Today I checked out those bubbles again, don´t know if it´s water that bubbles or if it´s something else.
Sprayed Leak Finder on to the base and took some pictures, just to let you see what I mean.





I didn´t have the tools to remove it today and I don´t like that the bolts seems so rusty...

/Mike

[J Wikoff]

Well I don't think that should happen.

The two 10 mm head bolts will resist. If you hit them with some penetrating oil and let them marinate, it'll help.