Blow off valve doesn't work

[Motorhead350]

I wasn't aware I had a problem until SOMEONE (:rolleyes:) told me my blow off valve doesn't work.

I have cleaned it and checked the wires, it seems fine. How do I test this? Is there a sound I have to listen for? Will the car perform differently if it's working or not?

To my knowledge this device just helps when I let off the throttle.

Tips or tricks?

Thanks!

[FordNut]

What are you talking about?

[bob6364]

how did this fella know it wasn't working?

[Motorhead350]

What are you talking about?

The blow off valve. What do I look for if it's not working, how can I tell if it actually is working?


how did this fella know it wasn't working?

I honestly have no idea.

[FordNut]

You probably don't have a blowoff valve. You most likely have a bypass valve. It has no wires unless you've found some kind of new-fangled gizmo. It is vacuum operated and should have three hoses connected to it. One is a small one that connects to the intake manifold. The other 2 should be about 1" or so. Some higher performance ones use as large as 2" hose and some have a flange on one end instead of two hoses. The 2 larger hoses connect to bypass the blower, one connection to the pipe between the air filter and blower, the other either after the blower or after the intercooler but before the throttle body.

One way to test it... disconnect the two larger hoses and make sure to remember which way it was connected so you can put it back together the right way. Connect a nipple between the two large hoses where the valve used to be. Leave the small vacuum line connected. Look at the valve, it should be closed. Start the car, the valve should open. Disconnect the vacuum line from the valve, it should close (put your thumb on the vacuum line so the car doesn't have a vacuum leak). Some of these steps may be overkill, but this is probably the safest way to test it.

[Motorhead350]

Thanks Brian. I'll do the testing tomorrow.

[FordNut]

I wasn't aware I had a problem until SOMEONE (:rolleyes:) told me my blow off valve doesn't work.


how did this fella know it wasn't working?

I wonder the same thing. Probably one of those cases where the best response would be to just ignore them.

[B.C. Bake]

What the heck are you guys talking about, :confused: blowing off what at deceleration? Were back to the PCV if it's blow by. I'm sure it's something I'm missing?:)

[RR|Suki]

What the heck are you guys talking about, :confused: blowing off what at deceleration? Were back to the PCV if it's blow by. I'm sure it's something I'm missing?:)

releases the air in the charge pipe when you let off the gas so that the air doesn't back up into the blower and cause un needed pressure

[FordNut]

With a blower or turbo you have to have a bypass valve or blowoff valve. Normally when the car is running at idle or part throttle, the valve is open and it prevents boost buildup. I dunno which way the air flows, it could be recycling the blower air while a little bit of the air goes to the engine, or air could even be drawn in through the valve instead of through the blower. When the throttle is opened, the vacuum which keeps the valve open goes away. The valve closes and allows boost to build. As boost builds, the higher the pressure in the intake manifold, the more pressure is on the inlet of the bypass valve's diaphragm which helps keep the valve tightly closed and prevents boost leaks through the valve. When the throttle is suddenly closed, if there is no bypass valve something will break. Maybe the blower, maybe the pipes, maybe something more serious. But since there is a bypass valve, it opens immediately when the throttle is closed and the boost goes away. If a bypass valve is too small, it can cause pipes to be blown off with a centrifugal system because it can't bleed off the boost fast enough and there is a pressure spike when the throttle closes.

[Zack]

Jeez guys, I looked down at the bypass valve, goosed the gas enough to see boost and the lever didnt budge.

It didnt work when I tested it.

I explained all this to Dominick when I did it.

[Egon Spengler]

Sounds like someone wasn't listening AGAIN....

Jeez guys, I looked down at the bypass valve, goosed the gas enough to see boost and the lever didnt budge.

It didnt work when I tested it.

I explained all this to Dominick when I did it.

[FordNut]

Maybe it wasn't the answer he wanted so he asked somebody else? Ask enough people a question and you'll probably get the answer you want to hear.

[Joe Walsh]

Dom, it seems that you are constantly having problems with your Marauder.
I know that you've said that you aren't mechanically inclined, so maybe a S/C DOHC Marauder wasn't the best choice for a daily driver...?
I would recommend a Trabant.

http://en.wikipedia.org/wiki/Trabant

It is a very simple vehicle that runs regardless of upkeep and maintenance.
It also gets good gas mileage!....and it's a very simple 2 cycle engine!

:hmmm:....Although you would have to remember to add oil to the gas at every fill up.

[Egon Spengler]

Give the kid a bicycle and a push on the seat and send him on his way!

Dom, it seems that you are constantly having problems with your Marauder.
I know that you've said that you aren't mechanically inclined, so maybe a S/C DOHC Marauder wasn't the best choice for a daily driver...?
I would recommend a Trabant.

http://en.wikipedia.org/wiki/Trabant

It is a very simple vehicle that runs regardless of upkeep and maintenance.
It also gets good gas mileage!....and it's a 2 cycle engine!

:hmmm:....Although you would have to remember to add oil to the gas at every fill up.

[Motorhead350]

Negative, TJ and Joe.

Zack said it wasn't working, he didn't mention how he did the test or how to solve the problem... simply "Your blow off valve doesn't work." That's all that was said. I didn't neglect to pay attention guys.

Now I know how to test it. If I couldn't maintain the car I wouldn't be driving it. So if it has 157K miles on it, (that I did all by myself BTW) I'd say I'm doing a decent job WITH help from people off of the site. That's about two to three times the amount of miles most of you have, so you would only expect there would be more for me to do especially with miles that high on a modified car.

That's just me though, you are all free to think what you'd like.

[justbob]

Dom, it seems that you are constantly having problems with your Marauder.
I know that you've said that you aren't mechanically inclined, so maybe a S/C DOHC Marauder wasn't the best choice for a daily driver...?
I would recommend a Trabant.

http://en.wikipedia.org/wiki/Trabant

It is a very simple vehicle that runs regardless of upkeep and maintenance.
It also gets good gas mileage!....and it's a very simple 2 cycle engine!

:hmmm:....Although you would have to remember to add oil to the gas at every fill up.
That car would make for a sick street rod!

[Egon Spengler]

Relax buddy... am just busting your nuggets!:beer:

Negative, TJ and Joe.

Zack said it wasn't working, he didn't mention how he did the test or how to solve the problem... simply "Your blow off valve doesn't work." That's all that was said. I didn't neglect to pay attention guys.

Now I know how to test it. If I couldn't maintain the car I wouldn't be driving it. So if it has 157K miles on it, (that I did all by myself BTW) I'd say I'm doing a decent job WITH help from people off of the site. That's about two to three times the amount of miles most of you have, so you would only expect there would be more for me to do especially with miles that high on a modified car.

That's just me though, you are all free to think what you'd like.

[Drewstang]

OMG really, another thread.

[Motorhead350]

OMG really, another thread.

Another useless post by you?