'97 F355 spider 5.2 capristo bypass valve vacuum line question

Appreciating all the wealth of knowledge on the forum. I've searched but can't seem to find an answer specific to this:

- I've recently replaced the stock bypass valve on my 97 spider 5.2 with a capristo valve - which works in reverse to the oem unit by staying open if no vacuum.

- I've also replaced the actuator with the provided capristo unit and my question is does it make a difference to use the vacuum pin on the vacuum crosspipe line the way the oem unit did or run the vacuum line to the actuator directly? (In this case I have followed the capristo instructions but have the cross line plugged into the proper outlet on the actuator.). In other words I'm able to use a shorter line in this case from the bypass.

- this feeds back thru the secondary as well I think.

- with motor running the valve pressurizes and bypass closes at idle in this config but I don't think it's opening at 2800 rpm. So perhaps I need to disconnect at the Y at the actuator and attach a longer line direct to the bypass? Would I also need to cap off the unused pin on the cross pipe then?

I'm also in search of better reinforced silicone tube - have been checking medical supply and others with no luck. Fear this tubing will suffer in the heat.


Thanks for any insights.

 

No one likes vacuum lines are perhaps it's my idiot question

 

Hopefully I'm understanding your question. But I disregarded the instructions and ran a shorter silicone hose off the factory alloy pipe like the oem one did. I didn't want a long hose when it made sense to just route it as per factory. I can assure you my bypass is working sensationally.

 

Also the silicone hose provided is fine so far. I'd be surprised Capristo didn't supply something adequate for the job.

 

Thank you! You understood my cryptic writing well. Ok, so perhaps I need to double check if all the lines are properly attached or perhaps get it out on road and see if will open up then. Wasn't warm enough yet likely.

I'll also see how the line holds up. I've given it a little more slack than the oem tube so as to keep it from touching anything.

Ed

 

I personally bypassed the factory metal tube and used the supplied hose. I was told the metal factory tube can develops cracks/leaks and the rubber hose is more reliable.

 

That's probably a safer bet.

How did you route then? From the y at the actuator? And did you plug the pin

 

So I've confirmed thru several trial and errors that I do have the valve and solenoid properly plumbed but it will still not open under any driving conditions ~ vacuum to the chrome pin, bypass to the 90 and the other left open.

But something is still wrong. The valve charges upon start and closes. Have confirmed via 12v bench test that the provided solenoid will open and close - however it's not opening the valve. Have done several test drives as well as idle and rev tests today. It also gives a little rattle upon throttle release and decelerate - like it's trying. Attached video of sound - a little hard to hear but it's there.

These are all brand new parts from capristo and now frustrated. It's acting almost like the vacuum is too much on both sides for the solenoid to overpower and release the valve, therefore opening.

Has anyone experienced this issue with the capristo valve and solenoid? From reading many posts here, these seem pretty bullet proof. Is it the solenoid that was provided - it's different than what is in the plumbing diagrams? See pic. Or is the valve itself adjustable - I'm not getting what I am doing wrong here. Thanks!

https://vimeo.com/200522211


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Sorry to hear your troubles. The solenoid supplied from Capristo is reversed from OEM. You may already know that. It closes when you start the car, the. Opens once the ecu tells it to. When I first got my car, the dealer had swapped mufflers before shipping. The Bypass wasn't opening because the connections on either side of the Bypass were overtightened and this was jamming the opening function. Loosened things up and it started working again.

Could be a vacume leak ?
Run the hose straight to the bypass valve. Not through the metal tube. See if it's any different.

That's all I got....

 

I'd have to go look. Can't remember. Just glad my problems came to an end !!

 

Appreciated. Yes, understand the concept with the springed capristo valve in open position without vacuum. Today ran lines every way possible - even ran a line direct from vacuum can to the bypass just to see. Also with bench tests of the solenoid, triple confirmed that it is opening with 12v and that it's internal plumbing is rational. Yet no dice.

Do you just loosen the screws on either side of the valve?




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I re-read your post more carefully - I think you meant the connection from the bypass to the exhaust system was overtightened (spring loaded bolts?). I'll check that too...I have a Tubi and perhaps I've got the bypass too tightly installed (although upon start the valve closes once vacuum without issue as can watch the mechanism move.). Will play with more today. Thanks again.

 

It's not the connection of bypass to exhaust. Just tried. Loosened as much as comfortable and no change. The butterfly moves freely as did before.

From bench testing the provided pierburg solenoid yesterday, noticed that it doesn't actually release the vacuum until the power is cut - meaning when a charge is applied, it's still holding vacuum. I think this is a wrong or faulty solenoid. That's all that's left in all the various diagnostics I've tried.

Can anyone who has a working Capristo bypass and solenoid send me the part number of the solenoid? Or a quick pic if shows the unit/ number. Even if installed and hard to see. It's definitely different than those in the diagram and from other posts.

Much appreciated gents. Ed

 

If the action is working at all, it's not overtightened as you found out. The fact that it closes on start up as it should means you are getting vacuum. My problem was that the system was working, but throwing a P1448 code. Goths Bypass TCU fixed that. Capristo told me that you can't run their Bypass with test pipes without getting a 1448, FYI.

I would call Capristo and have them send you another solenoid to try. They were very helpful to me. They will give you the correct vacuum pressure specs too.

How do you know it's not opening ? Just sound, or did you put a piece of tape on the action to see it ripped ?

 

Thanks for the note. Been working on this with a good mechanic and we've been monitoring under a variety of conditions. It's definitely not opening and all signs continue to point to the solenoid. I've got a note into both Capristo and the place I bought it from - they have responded and may send another solenoid hopefully....will keep touch.

 

Sounds good. Good luck.

 

Mine closes as well once the car warms up and the secondary air kicks out for a while then vacume builds and the two valves close.

Some how you are still maintaining vacume when the solenoid is open. Not sure why.

Did you tee in the vacume to the correct side of the existing valves?

 

Yes, have triple confirmed the plumbing is absolutely correct. Need to check and clean the contacts this weekend to see if that helps or get new solenoid.


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So if plumbing is correct your solnoid is not opening to atmosphere. Is the solenoid getting power correctly. If you have it wired backwards it also will just remain closed.

As you said if that is correct it could be the extra thermocouple on the exhaust bypass I think. I think it also is used to open the bypass. At least thats what it says in the WSM.

Thats all I got except you could exchange thermose with either right bank or left bank and plug in to check..

If you do this the bypass might work but you will throw a false sld on that side.

I dont think the last thing is correct about the thermos but I am not possitive exactly how it works for bypass. It might just be a safety to open so as to lower cat temps but it does not specifically explain it.


It wont hurt anything and is easy to try which is why I suggested it.

Maybe bob can chime in he understands that system well for the sdl setup.

 

Rule out the entire thermocouple system. Call Ricambi and get Goths Bypass TCU box.

I personally don't think the thermocouple controls the opening and closing of the bypass valve.

 

They don't. The bypass valve is controlled by the engine ECU based on gear selection, throttle position and engine RPM.

 

Correct.

The BP TC tells the ECU if the BP valve has opened or not based on the temps it detects. In my car I have the output of the BP SDECU tapped and in observing it real time under driving conditions the output voltage is around .8v in the closed position , warmed up and gets up to 1.4v when getting on it throttle wise when the valve opens.

I don't think the ECU does anything with this information but throw a CEL for the BP valve operation.

AS Skipp can attest with his straight pipe and Tubi header set up, and upstream change in the exhaust system can alter the temps detected at the BP TC and throw CELs. Using a fixed voltage ecu like Goths will defeat the BP SDECU function with no apparent detriment.

 

Unfortunately with Skipp's situation, we actually don't know the root cause of the problem. He elected to forgo further diagnostics and use Goth's hardware as his frustration was building. I don't blame him but I'd still like to know the root cause and issue without speculation.

 

To add more info, I was told by Capristo's tech that they're bypass valve can not be used with test pipes without throwing a 1448 CEL. Something to do with exhaust flow and temperatures. So, I do believe I got to the bottom of the issue. Goths box simply made it possible to run the Capristo bypass with test pipes. There was nothing wrong with the components of my car per Capristo, just the way it is with this combination of exhaust parts.

 

Thanks, Skipp. That's interesting. My guess would be too low of temperature given the free flow of test pipes. I still wonder if this would be an issue with the OEM bypass valve (Tubi headers, and test pipes) ???