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Boost solenoid causing KR?

Sudden

Sudden

New member
Everything was looking good, no KR. I'm not sure what boost I was getting after putting on a larger MAF, larger injectors, and the Overkill PCM. I do remember I had no KR. A while after that I received an error on the bypass valve solenoid. I replaced that and everything seemed OK. I didn't check the KR after that. Last week I went to OC MD to do some street racing and 2 to 3 * of KR pops up. Could it be that when I first added the last upgrades my boost was a little lower than it is now because I fixed the BPV Solenoid and now I'm getting more boost and more KR? I didn't make any real changes other than that. Boost shows up now as 10 to 11.
 


Why would the solenoid lower your boost? I've been looking for information on its operation, but haven't had a lot of luck other than traction control, something else and I recently found out it will dump boost if there's some kind of issue with the engine control, probably as a way to save the engine from damage haven't figured that one out yet. I thought it was either on or off but could be PWM controlled I guess, but I'm not sure. So if you're either on or off I wouldn't see how it would change your boost level alone.

Has the weather changed much since you last ran it that hard? Could the tune be ok in cooler weather and on the edge as its getting warmer out?

Jeff
 
The weather has gotten warmer. I thought maybe if the solenoid was going bad it might have let boost drop during my previous test. I don't know enough about it to know if it would have been on or off. I seemed to have boost when I got the error but I didn't check it. There's a video on youtude that shows a failed soleniod and the car has low boost but it has some.
 
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Thanks Bill, I think I must have been down on boost the last time I checked for KR. I did no real mods since then. I did find last night my I/C was a little low on water. I filled that and will check it again today. I'v fixed a leak several times but it keeps returning. I replaced the hoses so maybe I've got it this time.
 
Yeah, mine is preventing boost too. I'm only getting 3-4 lbs with vacuum attached. If I pull the vacuum off I get 8. I have a bad wheel speed sensor too, track light coming on randomly. Got a new hub so going to try that first and see if traction control had anything to do with it. If not I have 2 more selenoids to swap out.
 


Could you guys explain how and what mode will cause low boost? Is it the geometry of the linkage that does not keep as much spring pressure on to keep it closed and allows leakage?

As I understand it you have a 2 way valve that has an inlet and an outlet and exhaust on the other side. When the valve is open (don't know if it's NC or NO) it will direct pressure to the bottom of the BBV and cause it to open. When closed the inlet side is blocked and the pressure in the bottom of the BBV is let out via the other port on the valve and the little "filter" they have on there.

I am not doubting you guys I am just curious how it works and this particular failure mode. I am used to only having spring pressure keep the valve closed and no means of opening it but manifold vacuum.

Also how is it controlled? Is it simple on off or PWM?

Jeff
 
I think you have it pretty well figured out. I didn't know how that vent on the selenoid worked, your explanation makes sense.

If you don't have tuner, I'll post a picture of the tables later. Can't remembered off the top of my head, but I think there is traction, top speed cut, and duration? A couple others.
 
I don't have a tuner, I have only had my car for a little over a month or so, and I am just trying to get it to run as fast as it was stock. One of my sticking points is that the computer seems to be dumping boost on me all the time because of another issue. But I am just wondering how the valve could cause a lower than normal boost value. After I started thinking about it just now I could see if the valve is not seating properly and allowing boost to open the valve until it into equilibrium with the spring force trying to close the valve. Would this be a correct assumption?

Jeff
 
J57ltr said:
I don't have a tuner, I have only had my car for a little over a month or so, and I am just trying to get it to run as fast as it was stock. One of my sticking points is that the computer seems to be dumping boost on me all the time because of another issue. But I am just wondering how the valve could cause a lower than normal boost value. After I started thinking about it just now I could see if the valve is not seating properly and allowing boost to open the valve until it into equilibrium with the spring force trying to close the valve. Would this be a correct assumption?

Jeff
Click to expand...

You could always just remove the hose. That's the only way I'm getting full boost right now. Though I'd like to get mine working correctly too after the trouble of wiring it up.
 
05', Doesn't work tried that. The computer commands less throttle then throws the car in reduced engine power mode and shuts you out of the throttle. Sets it full rich and -15* timing until you shut the car off open the door (to kill power) and restart the car.

Jeff
 


J57ltr said:
05', Doesn't work tried that. The computer commands less throttle then throws the car in reduced engine power mode and shuts you out of the throttle. Sets it full rich and -15* timing until you shut the car off open the door (to kill power) and restart the car.

Jeff
Click to expand...

Oh. Drive by wire is a pain in the arse.

So here's what's in the pcm for boost control:
 
Hmm, that cataylst protection looks promising. Boost ramp rate, is looking like a possibility too. Thanks.

What does it take to set a code for the boost bypass valve?

Jeff

Sudden,

My thoughts are that its warmed up and now you aren't losing boost maybe that is why you are getting KR. I'm not sure you would have to speak with your tuner.
 
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