Venturi delete problems (now idle problem)
02-19-2006, 05:57 AM
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Venturi delete problems (now idle problem)
Hi,
I just replaced all of my vacuum lines and hoses with the Lindsey venturi delete kit, plus the vac line of course. Once I got the manifold on and everything hooked up I started it to see how it went. Now I am getting 17vac while cold, but the needle kinda twitches like it's occilating a bit.
I can feel that the engine seems to be idling a little rough, it kind of pulses by a couple of rpms. You can definately feel the car vibrating more than usual by both touching the front of car or by just sitting inside. The car drives fine and builds boost fine. Can removing the venturi have anything to do with this?
I attached the hoses like this:
1. Brake booster to manifold
2. ISV to manifold
3. ISV to IC pipe
During installation I had to remove the fuel pressure reg. The reason why I bring that up is that the roughness of the engine almost seems like it's getting too much fuel and bogging down. Maybe I somehow upset or damaged the idle
stablizer valve. It is only rough during idle and I think that I can smell a rich condition in the exhaust.
Is there anything you guys can possibly think of that would cause this?
Thanks, ~Josh
I just replaced all of my vacuum lines and hoses with the Lindsey venturi delete kit, plus the vac line of course. Once I got the manifold on and everything hooked up I started it to see how it went. Now I am getting 17vac while cold, but the needle kinda twitches like it's occilating a bit.
I can feel that the engine seems to be idling a little rough, it kind of pulses by a couple of rpms. You can definately feel the car vibrating more than usual by both touching the front of car or by just sitting inside. The car drives fine and builds boost fine. Can removing the venturi have anything to do with this?
I attached the hoses like this:
1. Brake booster to manifold
2. ISV to manifold
3. ISV to IC pipe
During installation I had to remove the fuel pressure reg. The reason why I bring that up is that the roughness of the engine almost seems like it's getting too much fuel and bogging down. Maybe I somehow upset or damaged the idle
stablizer valve. It is only rough during idle and I think that I can smell a rich condition in the exhaust.
Is there anything you guys can possibly think of that would cause this?
Thanks, ~Josh
Last edited by silverbullet; 02-19-2006 at 06:33 PM.
02-19-2006, 01:45 PM
#5
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Originally Posted by special tool
Double check that thee fuel pressure regulator has good vacuum.
You WILL blow your headgasket without it.
You WILL blow your headgasket without it.
02-19-2006, 03:34 PM
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I looked over the engine and I am pretty sure all of my vac lines are right. The vac reading occilates between 17 and 18 psi. Fuel pressure is set to 43.5 with vac line disconnected. Vacuum on FPR is 17-18 psi. Engine is idling at 800-850 rpm after idling for 5 minutes.
When I was working with the idle stablizer valve, I broke it off it's mount. It had two rubber bushing between it and the metal bracket that it sat on. Those were dryrotted and fell apart, so I had to bolt it back up without the bushings. What exactly does the ISV do? Now I'm just shooting in the dark as I have no clue to what this could be.
Thanks
~Josh
When I was working with the idle stablizer valve, I broke it off it's mount. It had two rubber bushing between it and the metal bracket that it sat on. Those were dryrotted and fell apart, so I had to bolt it back up without the bushings. What exactly does the ISV do? Now I'm just shooting in the dark as I have no clue to what this could be.
Thanks
~Josh
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02-19-2006, 08:09 PM
#11
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Setting the Idle on the 944 Turbo:
To do it correctly and thoroughly, it is a four step process.
1) Setting the hard stop. Car is not running. The purpose of the hard stop adjustment is to keep the throttle plate from binding or landing in the throttle body bore to hard. It's purpose is "not" to set the idle. Loosen the jam nut (8mm). Loosen the screw with a small straight blade screwdriver slowly and carefully until the screw turns loose. With a gentle touch, slowly turn the screw back in until you can feel it touch the stop. From there, turn it another 1/8 turn. Tighten the lock nut back down. If you have the intercooler pipe off, you would barely be able to detect that the throttle plate moved.
2) Setting the Throttle Position Sensor (TPS). Car is not running. A correctly adjusted throttle position sensor will make a clicking sound when you just roll the throttle off the stop. Place you fingers on the throttle cam and rotate the throttle open off idle. If it does not click, it's not adjusted properly. If it rotates several degrees before clicking, it's not adjusted properly. Loosen the two phillip screws on the TPS just enough to allow you to rotate it with a slight effort. Rotate the TPS to where when you rotate the throttle cam, it clicks when you're just off the stop or about 1 degree of rotation. Then tighten the two TPS screws back down.
3) Jumping the Idle Stabilizer. Car is not running. You will need a short piece or wire (3-4") with both ends stripped bare. Place the ends of the wire in the terminals "B" and "C" pictured below. This will put the Idle Stabilizer in a central position of it's movement when the car is running.
4) Adjusting the idle RPM. With the previous three steps completed, you will be setting the idle RPM. With the car in neutral and the emergency brake on, start the car. Turn off the A/C if on. Let the car come up to normal operating temperature. The idle RPM is adjusted by turning the idle screw located on the top of the throttle body. Normally it will be approximately 1/2 turn open from fully seated down (clockwise).
To do it correctly and thoroughly, it is a four step process.
1) Setting the hard stop. Car is not running. The purpose of the hard stop adjustment is to keep the throttle plate from binding or landing in the throttle body bore to hard. It's purpose is "not" to set the idle. Loosen the jam nut (8mm). Loosen the screw with a small straight blade screwdriver slowly and carefully until the screw turns loose. With a gentle touch, slowly turn the screw back in until you can feel it touch the stop. From there, turn it another 1/8 turn. Tighten the lock nut back down. If you have the intercooler pipe off, you would barely be able to detect that the throttle plate moved.
2) Setting the Throttle Position Sensor (TPS). Car is not running. A correctly adjusted throttle position sensor will make a clicking sound when you just roll the throttle off the stop. Place you fingers on the throttle cam and rotate the throttle open off idle. If it does not click, it's not adjusted properly. If it rotates several degrees before clicking, it's not adjusted properly. Loosen the two phillip screws on the TPS just enough to allow you to rotate it with a slight effort. Rotate the TPS to where when you rotate the throttle cam, it clicks when you're just off the stop or about 1 degree of rotation. Then tighten the two TPS screws back down.
3) Jumping the Idle Stabilizer. Car is not running. You will need a short piece or wire (3-4") with both ends stripped bare. Place the ends of the wire in the terminals "B" and "C" pictured below. This will put the Idle Stabilizer in a central position of it's movement when the car is running.
4) Adjusting the idle RPM. With the previous three steps completed, you will be setting the idle RPM. With the car in neutral and the emergency brake on, start the car. Turn off the A/C if on. Let the car come up to normal operating temperature. The idle RPM is adjusted by turning the idle screw located on the top of the throttle body. Normally it will be approximately 1/2 turn open from fully seated down (clockwise).
02-19-2006, 08:36 PM
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Originally Posted by Ski
Setting the Idle on the 944 Turbo:
To do it correctly and thoroughly, it is a four step process.
1) Setting the hard stop. Car is not running. The purpose of the hard stop adjustment is to keep the throttle plate from binding or landing in the throttle body bore to hard. It's purpose is "not" to set the idle. Loosen the jam nut (8mm). Loosen the screw with a small straight blade screwdriver slowly and carefully until the screw turns loose. With a gentle touch, slowly turn the screw back in until you can feel it touch the stop. From there, turn it another 1/8 turn. Tighten the lock nut back down. If you have the intercooler pipe off, you would barely be able to detect that the throttle plate moved.
2) Setting the Throttle Position Sensor (TPS). Car is not running. A correctly adjusted throttle position sensor will make a clicking sound when you just roll the throttle off the stop. Place you fingers on the throttle cam and rotate the throttle open off idle. If it does not click, it's not adjusted properly. If it rotates several degrees before clicking, it's not adjusted properly. Loosen the two phillip screws on the TPS just enough to allow you to rotate it with a slight effort. Rotate the TPS to where when you rotate the throttle cam, it clicks when you're just off the stop or about 1 degree of rotation. Then tighten the two TPS screws back down.
3) Jumping the Idle Stabilizer. Car is not running. You will need a short piece or wire (3-4") with both ends stripped bare. Place the ends of the wire in the terminals "B" and "C" pictured below. This will put the Idle Stabilizer in a central position of it's movement when the car is running.
4) Adjusting the idle RPM. With the previous three steps completed, you will be setting the idle RPM. With the car in neutral and the emergency brake on, start the car. Turn off the A/C if on. Let the car come up to normal operating temperature. The idle RPM is adjusted by turning the idle screw located on the top of the throttle body. Normally it will be approximately 1/2 turn open from fully seated down (clockwise).
To do it correctly and thoroughly, it is a four step process.
1) Setting the hard stop. Car is not running. The purpose of the hard stop adjustment is to keep the throttle plate from binding or landing in the throttle body bore to hard. It's purpose is "not" to set the idle. Loosen the jam nut (8mm). Loosen the screw with a small straight blade screwdriver slowly and carefully until the screw turns loose. With a gentle touch, slowly turn the screw back in until you can feel it touch the stop. From there, turn it another 1/8 turn. Tighten the lock nut back down. If you have the intercooler pipe off, you would barely be able to detect that the throttle plate moved.
2) Setting the Throttle Position Sensor (TPS). Car is not running. A correctly adjusted throttle position sensor will make a clicking sound when you just roll the throttle off the stop. Place you fingers on the throttle cam and rotate the throttle open off idle. If it does not click, it's not adjusted properly. If it rotates several degrees before clicking, it's not adjusted properly. Loosen the two phillip screws on the TPS just enough to allow you to rotate it with a slight effort. Rotate the TPS to where when you rotate the throttle cam, it clicks when you're just off the stop or about 1 degree of rotation. Then tighten the two TPS screws back down.
3) Jumping the Idle Stabilizer. Car is not running. You will need a short piece or wire (3-4") with both ends stripped bare. Place the ends of the wire in the terminals "B" and "C" pictured below. This will put the Idle Stabilizer in a central position of it's movement when the car is running.
4) Adjusting the idle RPM. With the previous three steps completed, you will be setting the idle RPM. With the car in neutral and the emergency brake on, start the car. Turn off the A/C if on. Let the car come up to normal operating temperature. The idle RPM is adjusted by turning the idle screw located on the top of the throttle body. Normally it will be approximately 1/2 turn open from fully seated down (clockwise).
02-20-2006, 01:21 AM
#15
Rennlist Member
Damn, I'd be ecstatic if my car made 17 inches at cold idle. Course the altitude I'm at has something to do with it, but I'm nowhere close to that, and neither is Greg East, who lives in town with me and has replaced all his lines...