Interesting...Evo engine finding
#16
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Yeah based on the picture, yours is placed AFTER the selonoid. You can either get new hoses and put the T in before the selonoid, or live with the current condition.
If you are having real problems with it, you may also just bypass the selonoid by putting a hose directly from the manifold to the FPR, and placing your boost T in the middle. It could be a problem if the selonoid activated under high boost leaving you with 19 psi less of fuel pressure.
Here is a pic with the fuel pressure selonoid highlighted. Note the line in the pic is the one coming off the manifold. The line you have your boost gauge plummed into is the outlet of the selonoid which is located under it.
If you are having real problems with it, you may also just bypass the selonoid by putting a hose directly from the manifold to the FPR, and placing your boost T in the middle. It could be a problem if the selonoid activated under high boost leaving you with 19 psi less of fuel pressure.
Here is a pic with the fuel pressure selonoid highlighted. Note the line in the pic is the one coming off the manifold. The line you have your boost gauge plummed into is the outlet of the selonoid which is located under it.
Last edited by TearItUpSports; Jul 28, 2004 at 07:29 AM.
#17
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Originally Posted by KillaSweep
I installed my T fitting according to this boost gauge install write up. Here is the picture from the website..... I have seen it installed on the next hose over too.....Perhaps I just need to move the location and it restricting vacuum there is normal?
Brian
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I will mention it to the dealership. I think I will move the T fitting, just to be safe, but it sounds very possible that the little syllanoid would control vacuum to control the pressure going into the fuel pressure regulator. I will just check with the dealership to confirm that the no vacuum thing is a proper function. When they started the car and it did that they thought I had a fault boost gauge or something....then again they still haven;t figure out how to fix the damn thing. lol. I smell lemons!
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Originally Posted by siantjab
Like I said, mine is T'd in before the intake manifold and reads prefect.
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The solenoid stays closed during cold starts and some warm starts to increase the fuel pressure. When the solenoid valve closes the vacuum from the intake manifold doesn't get to the fuel pressure regulator, thus you run the static fuel pressure (i.e. higher than normal) at idle. It shouldn't affect boost readings during normal driving but it will show 0 when the valve is close even when the car is running vacuum. The ideal place to install the T is between the vacuum source and the solenoid valve.
Brian
Brian
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Originally Posted by eve-slow
I've heard if you cut in BEFORE the selonoid, you often won't get any boost readings for the first few minutes your car is running. I have mine after the selonoid and it has worked fine since install.
Also to whoever asked, yes plumbing it after the selonoid could result in lower pressure reading, since there will be an inherent pressure drop across the selonoid, a pressure drop from the T fitting, pressure drop due to the length of small tube from the intake manifold, and a pressure drop from the length of the hose between the T and your gauge (usually several feet).
The shorter and straighter the line, the more accurate your gauge would be. Ideally it should not be T'd in but rather directly connected to the manifold, but that is usually not possible. With a MAP sensor where an EMS or something is using it for engine management, you should have a direct connection to the manifold with no T's, and a short line.