Help: Boost Pressure Gauge not working?

dbev77 · #1 03-03-2014

I just bought this 2000 Saleen on Friday. Love it! But there is something missing from I think its called the Boost Pressure actuator. I'm not sure what it it's called. But there looks like a vacuum hose missing from it. Attached is the pic of it. Can anyone tell me what it is that's missing and how I go about ordering it and putting it on? It did have major vacuum sucking in but after I told the dealership about it they (magically) stopped sucking any air now. Any ideas what they did? Or is it hurting anything with nothing being on that valve? Sorry, not too familiar with superchargers. Any info would help me. Thanks for your time.

dbev77 · #2 03-03-2014

Sorry, I circled it here on this pic

tennesseemustangperformance · #3 03-03-2014

Quote:

Originally Posted by dbev77

Sorry, I circled it here on this pic

Looks like they just put a $0.10 vacuum cap on the port. No biggie, won't hurt a thing, your gauge just won't function. If you are concerned with reading boost pressure, you can run a 1/8" vacuum line to the cabin and hook it to a mechanical gauge. Piece of cake. If you do decide to do this, I will walk you through the process.

Coderedsaleen · #4 03-03-2014

That is suppose to have no hose, it just vents to the atmosphere. Look at the lever that is attached to it, you will see that it is touching the screw, when you start the car the lever will move down. This is to open the boost bypass to allow air to pass through the supercharger. When you mash the gas the vacuum will drop and the bypass valve will close to build up pressure in the supercharger creating boost pressure. Do not put anything on the there. Your boost gauge has nothing to do with that port.

Your boost gauge sending unit is located under the inlet of the supercharger. It is a big goldish looking sending unit and has one wire going to it.

dbev77 · #5 03-03-2014

Quote:

Originally Posted by Coderedsaleen

That is suppose to have no hose, it just vents to the atmosphere. Look at the lever that is attached to it, you will see that it is touching the screw, when you start the car the lever will move down. This is to open the boost bypass to allow air to pass through the supercharger. When you mash the gas the vacuum will drop and the bypass valve will close to build up pressure in the supercharger creating boost pressure. Do not put anything on the there. Your boost gauge has nothing to do with that port.

Your boost gauge sending unit is located under the inlet of the supercharger. It is a big goldish looking sending unit and has one wire going to it.

Wow, thanks for the reply. That solved a lot of confusion. Yeah, when the car was off we noticed the lever touching the screw and thought that wasn't supposed to do that. I'm glad it is lol. So do you know why there was a lot of suction when my dad put his finger on that open port? But now there isn't any. Guess we will look at the sending unit and see if its connected correctly so this thing will work. That's the place to check right? Thanks again.

Coderedsaleen · #6 03-03-2014

The only reason that you would have suction out of that port is if the bypass valve was leaking. They must have replaced it.

Yes check the sending unit to make sure that the wire is attached. If it is connected then you may have a bad sending unit, ground or gauge.

dbev77 · #7 03-03-2014

Quote:

Originally Posted by Coderedsaleen

The only reason that you would have suction out of that port is if the bypass valve was leaking. They must have replaced it.

Yes check the sending unit to make sure that the wire is attached. If it is connected then you may have a bad sending unit, ground or gauge.

Ok sounds good. It looks like that actuator where the lever is isn't working or I'm confused. When the car is off its all the way down to the screw. When it is idle the lever is all the way up against the bolt on the supercharger. Is it backwards or is that correct? Sorry for questions but looks like your the only one that replied. Thanks for the info though.

Coderedsaleen · #8 03-03-2014

The lever is in relation to the butterfly valve in the supercharger. It should be down (open) when running and up (closed) when in a boosting state.

It is up when not running because there is no vacuum on it. When you are running the engine at idle the vacuum sucks the diaphragm down to open the bypass valve and closes when vacuum drops off to create pressure in the supercharger.

dbev77 · #9 03-03-2014

Quote:

Originally Posted by Coderedsaleen

The lever should be down when running and up when not running. The lever is in relation to the butterfly valve in the supercharger. Open when not in boost and closed when in boost.

So the mechanic put it in backwards lol. Didn't think that's possible lol. Really appreciate the information.

Coderedsaleen · #10 03-03-2014

Another thing that I just noticed, because I went and looked at my old 2V, that bypass valve is from a 2003/2004 Cobra or similar. The one that is OEM from Saleen does not have that other port on it but my 2003 4V Cobra engine has the same as yours. Can you post pics from the side?

Coderedsaleen · #11 03-03-2014

Here is a pic of the OEM Saleen bypass, it lays on it side.

Coderedsaleen · #12 03-03-2014

Here is a pic of a 2003 Cobra bypass (my engine). See the difference? The Cobra had that lower port to suck it open to bleed off boost to ensure an over boost didn't happen. I got rid of all that when I did my engine conversion.

Coderedsaleen · #13 03-03-2014

Hope this helps?

dbev77 · #14 03-03-2014

Quote:

Originally Posted by Coderedsaleen

Here is a pic of a 2003 Cobra bypass (my engine). See the difference?

Wow it does look different! This is what happened. When we got it from the dealership we noticed that there was vacuum sucking in on the port that's supposed to go out in the atmosphere. When we told them, it looks like they switched it with a Cobra one and put the lever backwards. Because the lever is working backwards do I get 0 boost? Or is it just the hose connection as you said? Here are my pics by the way.

Coderedsaleen · #15 03-03-2014

Sounds like it is working backwards. When you are running it take the vacuum line off, you should hear a difference in the sound of the engine.

dbev77 · #16 03-03-2014

Quote:

Originally Posted by Coderedsaleen

Sounds like it is working backwards. When you are running it take the vacuum line off, you should hear a difference in the sound of the engine.

Yeah we did that already. There is vacuum in the other hose and we hear a difference in the sound.

Coderedsaleen · #17 03-03-2014

When you take the vacuum line off the lever is suppose to move into the closed position due the spring. It should open when vacuum is applied.

Put your finger over the end of the hose to prevent the vacuum leak and move the lever to see what position the butterfly is in. You will hear differences in the engine to. They have the bypass valve mounted weird to actuate the arm.

Coderedsaleen · #18 03-03-2014

Zooming to your pics I can see the arm is horizontal against the intake, this is correct when not running. When you are running the car it should be pulled up off towards the actuator.

dbev77 · #19 03-03-2014

Quote:

Originally Posted by Coderedsaleen

Zooming to your pics I can see the arm is horizontal against the intake, this is correct when not running. When you are running the car it should be pulled up off towards the actuator.

Hmm so it is correct? Ya when its not running, the lever is against the screw, black piece and all. When I start it, it goes off the screw.

Coderedsaleen · #20 03-03-2014

Quote:

Originally Posted by dbev77

When the car is off its all the way down to the screw. When it is idle the lever is all the way up against the bolt on the supercharger. Is it backwards or is that correct?

This is correct.

Sorry for all the back and forth but troubleshooting on the forum can be time consuming.

dbev77 · #21 03-03-2014

Quote:

Originally Posted by Coderedsaleen

This is correct.

Sorry for all the back and forth but troubleshooting on the forum can be time consuming.

Its ok lol. So let me get this straight. Which way is open on the lever? Up or down? Because when the car is on and when we rev it, the lever doesn't move at all. The only time it moves is when we shut the car off, then it rests on the screw or we turn the car on, then it moves off the screw. We just need to know which is open and which is closed. Maybe I'm not understanding the lingo lol.

Coderedsaleen · #22 03-03-2014

Okay with the bypass valve working behind us your boost pressure gauge may have a bad sending unit, ground, gauge or combination. I would check to make sure the wire is still attached and not cut some where up the line.

Coderedsaleen · #23 03-03-2014

Quote:

Originally Posted by dbev77

Its ok lol. So let me get this straight. Which way is open on the lever? Up or down? Because when the car is on and when we rev it, the lever doesn't move at all. The only time it moves is when we shut the car off, then it rests on the screw or we turn the car on, then it moves off the screw. We just need to know which is open and which is closed. Maybe I'm not understanding the lingo lol.

LOL, Lever up is open (during idle and normal driving), Lever down is closed (during boost or when engine is off).

Coderedsaleen · #24 03-03-2014

Saleen Series II Supercharger, you see it has a different bypass valve and actuator.

Post a full pic of your engine bay please. See what we are working with.

Coderedsaleen · #25 03-03-2014

You must have a series I supercharger?

dbev77 · #26 03-03-2014

Yeah I have a series I. Here is the engine bay.

Coderedsaleen · #27 03-03-2014

Regardless of which one you have they all work on the same principle. It shows the same bypass that you have.

Coderedsaleen · #28 03-03-2014

I think after all that (Shewww) it is a sending unit, ground or gauge issue.

dbev77 · #29 03-03-2014

Quote:

Originally Posted by Coderedsaleen

Regardless of which one you have they all work on the same principle. It shows the same bypass that you have.

Yeah true. Just thought it wasn't working. I hear the (whine) when I drive. Just making sure I have boost since we think the gauge is hooked up. But we will check that wire that you were talking about. Just thought that lever is supposed to move when I rev the engine. Sorry for all this. I'm new to superchargers if you didn't know already, haha! Just want to make sure all this is working. You know how sloppy mechanics are. Especially when they are trying to push a Saleen out the door.