Hi all. I don't have any CELs but I am making no to low, maybe 2lbs of boost. What is the best way to diagnose if it is the bypass valve or the bypass solenoid? I searched around the forum and read a bunch of past posts, unfortunately all or most of the referenced info is missing. Meaning there are links to click for more info and so forth but none of them work anymore.

Thanks in advance all!
-Tony

 

First see if the arm connected to the bypass valve is movable.

 

So here is something I did try. Tell me if I am missing something here. I did find a couple helpful forum posts from the links below. Not sure if I approached this correctly. I took the from hose off the bypass solenoid and plugged it - no change. I then took the rear hose off the solenoid (there was vacuum there) and I lined it up with the front bypass solenoid hose and wrapped some electrical tape around it. That should have put vacuum directly to the top half of the bypass valve, right? Still no change. So I suspect that the diaphragm may be bad in the bypass valve.

Does any of that make sense or am I totally missing something?

Thanks again

 

@ECaulk Thanks for your reply. Yes, it seems to move freely.

 

You should remove and plug the bottom bpv line (from bpv to solenoid) leave the one connected to the supercharger (top of bpv to supercharger body). If it boosts full again the solenoid is like bad.

Here is another thread with good info : https://www.cobaltss.net/forums/2-0l...-boost-321758/

 

My bad. It was the lower hose from the solenoid to the BPV i removed and plugged. No difference.

Hose from output side of solenoid to the lower input of the bypass valve.

 

Those lines look dry rotted and will need to be replaced anyways. Start by replacing the lines, its possible the boost is leaking from the supercharge to the upper nipple on the bpv preventing the valve from closing

 

Looks like two different size diameters, any ideas on what they are? I'll get some ordered!

Thanks.

 

No I don't know the size. I'd just go to a parts store pull the line and say I need a few feet of this size line

 

I'll run out at lunch tomorrow.

 

So a couple quick things. I did get me some vacuum hose. The stuff they gave me was the wrong inner diameter and was too loose. But looking at the hoses I have the outside is dry rotted but the hose itself seems pretty solid. I know that doesn't tell the whole story - but I have bigger problems. I am getting frustrated that there doesn't seem to be much information on the layout and inner workings of the M62 Eaton supercharger. I took a shot and ordered a bypass valve from ZZP. That is going back, I may still have a bad bypass valve but what they sent is not a direct replacement. See the picture. There is no flange with the "micro adjustment" for the wastgate or butterfly whatever folks call it. Also, once I had the bypass valve off. I worked the linkage and moved the "butterfly", I removed the air intake hose and moved it by hand. The bypass valve linkage and the "butterfly" moved independently of each other. Is that correct? And clearly there is an electric motor assembly of some sort which works that "butterfly" valve. So now I am not even sure what I am looking at. And to add to the fun, I dropped one of the 10mm bolts that hold the bypass valve in place and it's sitting down there somewhere in the engine where I will never find it! I am back to square one and am wondering if I need to take the supercharger out and rebuild it or something because there may be some internal linkage that is not working.

 

Mine goes low to no boost at times and it is always the same problem. I need top put a drop of oil on the boost valve butterfly shaft. It sticks and needs lube. A drop off the dipstick works in a pinch. Located at tip of screwdriver in pic. These type of butterfly's like a throttle body will also stick If allowed to close to far. The stop needs to be set but DFW that unless your pretty sure yours is jacked and sticking. Disclaimer mine is run in the dirt and not controlled by the factory computer crap.
Before you pull off the supercharger there is a way to disable that valve so it never goes into bypass. I do not remember exactly the best way to do that and you do not want to leave it like that but if you bypass it’s operation it should run full boost. Good way to troubleshoot...Good luck!

 

@Stumpalump Thanks for your reply! Yeah, the original BPV seemed to operate freely. I also was able to move the linkage to the "butterfly" or whatever folks call it and that seems to move freely too.

I tried swapping in the new one from ZZP and that didn't help.