Valve cover broken at PCV boss, will this cause my rough idle?

[markdr7]

I've been having a issue the last two days with a rough and fluctuating idle. I thought it might be the boost controller that I just hooked up or the air/fuel gauge that I just installed. I've double checked and they are hooked up right. The boost controller is not working either by the way. I looked this morning and I found a hole in the back side of the valve cover about the size of a dime. There is a hose screwed into the valve cover and it is there that the hole is. At idle it is pouring air out. I was wondering if the hole would cause any of these issues. The car runs great other wise. Just when idling it jumps from 700 to 200 rpms and occasionally will die. Any suggestions are appreciated. Thanks

 

[sirsol66]

Here's something to answer your question: Notice that there's a vac line running from the side of your VC to your intake, AFTER your maf? Because of this hole you have in your VC, your essentially feeding your car quite a bit of air that is not accounted for by your maf. This can cause your rough idle and other issues. I'd try to fix it asap.

 

[markdr7]

That makes since. I think I'm gonna try and use some jb weld for a temp fix till I get a new valve cover. Unless someone has a better idea on a temp fix.

 

[Dsmj89]

It could be possible it is the problem of your funny idle. I would get a used valve cover on ebay for cheap asap. For the meantime, take out the screw and jb weld it shut.

 

[joyfil2001]

I've been having a issue the last two days with a rough and fluctuating idle. I thought it might be the boost contoller that I just hooked up or the air/fuel gauge that I just installed. I've double checked and they are hooked up right. The boost controller is not working eigthier by the way. I looked this morning and I found a hole in the back side of the valve cove about the size of a dime. There is a hose screwed into the valve cover and it is there that the hole is. At idle it is pouring air out. I was wondering if the hole would cause any of these issues. The car runs great other wise. Just when idleing it jumps from 700 to 200 rpms and ocassionally will die. Any suggestions are appreciated. Thanks

Any way you can get a pic? I'm very curious to see this hole.

 

[markdr7]

Do you guys think that it might be the reason that the new boost controller is not adjusting the boost? I can only get a reading of 11 psi on the gauge no matter if I turn the controller up or shut it completly off.

 

[markdr7]

I'll get a picture of it on here in just a few minutes.

 

[joyfil2001]

Do you guys think that it might be the reason that the new boost controller is not adjusting the boost? I can only get a reading of 11 psi on the gauge no matter if I turn the controller up or shut it completly off.

It sounds like you may have the boost controller hooked up incorrectly. You are just running wastegate if it is opening at 11psi. Double check your installation. How are your lines running?

 

[Dsmj89]

Wether you have a boost controller or not, it shouldn't affect idle at all unless you hooked it up wrong. Re-check your lines.

 

[joyfil2001]

Wether you have a boost controller or not, it shouldn't affect idle at all unless you hooked it up wrong. Re-check your lines.

What he said.

 

[markdr7]

Heres the picture of the hole I have. And the boost controller is hooked up with a line from the wastgate to the controller, and the other is hhked up to the nipple that is coming off of the turbo. I diconnected the old t fitting that ran over to the boost controller solenoid.I also capped off the nipples on the boost controll solenoid. I think that I did it right maybe not though.

Excuse the flaking paint on the vc. I didn't paint it, I bought it that way.

 

[joyfil2001]

Heres the picture of the hole I have. And the boost controller is hooked up with a line from the wastgate to the controller, and the other is hhked up to the nipple that is coming off of the turbo. I diconnected the old t fitting that ran over to the boost controller solenoid.I also capped off the nipples on the boost controll solenoid. I think that I did it right maybe not though.

You need a new valve cover. From the way you described it sounds like the boost controller is hooked up right. What kind of boost controller is it?

 

[No_Skillz]

Did you do a BLT before you started suspecting your MBC? You should.

 

[markdr7]

Its a Hallman Contoller. I'm going to do a boost leak test tomorrow. I was thinking that I have leaks, but if I turned the controller up you would think that it would still turn the boost up. It would just not hold it very long. But it does nothing at the moment.

I bought some jb weld I'm going to put that on there for now. We'll see if it fixes the rough idle after it cures up. Then i'll do the boost leak test

 

[joyfil2001]

That hole in your valve cover is probably a massive leak.

 

[markdr7]

I'm sure it is a big leak. I'm not sure whether or not it has anything to do with idle, but hopefully it will fix it. I'll post an update after I test it tomorrow.

 

[joyfil2001]

I'm sure it is a big leak. I'm not sure whether or not it has anything to do with idle, but hopefully it will fix it. I'll post an update after I test it tomorrow.

A big leak at that spot can have a major impact on the idle. Try the jbweld and post back. If that makes it any better you need to get a new valve cover. Hell, you need one anyway so you might as well order one. There is one in the clasifieds right now for $35.

 

[No_Skillz]

I was thinking that I have leaks, but if I turned the controller up you would think that it would still turn the boost up. It would just not hold it very long. But it does nothing at the moment.

Your pressure source is not static, so it would not pressurize to a peak and drop down. Your turbo is constantly blowing so it would reach a steady state pressure, not peak.

In other words, imagine a pinhole in a balloon. If you blow into it, it will swell up (higher PSI) then slowly deflate (lower PSI). This is because you have to stop and take a breath, i.e. becoming static.

On the other hand, imagine an air compressor blowing into the balloon. It will reach a certain size until the air excaping through the pinhole is equal to that of the air being introduced by the compressor. The size at this point stays constant.

 

[xezerax]

when i changed my injectors i accedently left that line off when i first started the car and my idle was rough.

 

[markdr7]

Well I finally Jb welded that hole that I had. Didn't get to do it as soon as I wanted to, it ended up snowig pretty good here. The weld worked really well, it doesn't leak at all there now. The car idles just like it's supposed to. I guess that solved that issue. I went to get emissons today on it, and it failed pretty bad. It had too many hydrocarbons I think that's what its called. I guess thats the next step that I have to do to the car figure that out. Thanks for the responses about the valve cover though.