vacuum / IAC stuff
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Senior Member
Joined: Dec 2000
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From: Raleigh, NC, USA
vacuum / IAC stuff
I was wanting to check for a vacuum leak... Can I safely plug every vacuum line coming off the throttle body and intake manifold? With the exception of the PCV valve, that is.
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89 iroc-z 305 tbi
k&n filtercharger, open element air filter. nuffin' else
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89 iroc-z 305 tbi
k&n filtercharger, open element air filter. nuffin' else
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Joined: Jan 2000
Posts: 19,658
Likes: 310
Enkil,
You should be able to remove and cap or plug all of the lines. Expect a few changes when you do, however:
When you remove the line to the power brake booster, there will be no power assist for the brakes, and the pedal force required to stop the car will be very high.
When you remove the line from the fuel pressure regulator on a TPI engine, the fuel pressure should rise about 6 PSIG. This is not a problem in the short term. Actually, you can operate this way for a long time with no real problems, other than higher fuel consumption and pushing the ECM harder to trim fuel pulses to maintain a satisfactory exhaust oxygen level.
Removing the vacuum from the MAP sensor on a TBI engine will cause the ECM to set a DTC and revert to the base lookup tables for fuel and spark offsets.
You can expect the EVAP canister not to purge, and the EGR valve to remain closed. The HVAC controls will not operate and all air will be routed through the defroster ducts (the default position).
Your cruise control will not operate.
Removing the line from the Air Injection Reaction system diverter valve will cause all injection air to be dumped to the catalytic converter. Thsi should pose no operational problems.
You can disconnect the PCV vacuum hose and cap it, but the change in idle air flow will almost certainly cause the idle speed to reduce. The IAC may try to compensate. You should be able to operate this way for several days without contaminating the oil too severly.
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Later,
Vader
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"I'm'a do Things My Way - It's My way or the Highway."
Adobe Acrobat Reader
You should be able to remove and cap or plug all of the lines. Expect a few changes when you do, however:
When you remove the line to the power brake booster, there will be no power assist for the brakes, and the pedal force required to stop the car will be very high.
When you remove the line from the fuel pressure regulator on a TPI engine, the fuel pressure should rise about 6 PSIG. This is not a problem in the short term. Actually, you can operate this way for a long time with no real problems, other than higher fuel consumption and pushing the ECM harder to trim fuel pulses to maintain a satisfactory exhaust oxygen level.
Removing the vacuum from the MAP sensor on a TBI engine will cause the ECM to set a DTC and revert to the base lookup tables for fuel and spark offsets.
You can expect the EVAP canister not to purge, and the EGR valve to remain closed. The HVAC controls will not operate and all air will be routed through the defroster ducts (the default position).
Your cruise control will not operate.
Removing the line from the Air Injection Reaction system diverter valve will cause all injection air to be dumped to the catalytic converter. Thsi should pose no operational problems.
You can disconnect the PCV vacuum hose and cap it, but the change in idle air flow will almost certainly cause the idle speed to reduce. The IAC may try to compensate. You should be able to operate this way for several days without contaminating the oil too severly.
------------------
Later,
Vader
------------------
"I'm'a do Things My Way - It's My way or the Highway."
Adobe Acrobat Reader
Thread Starter
Senior Member
Joined: Dec 2000
Posts: 886
Likes: 0
From: Raleigh, NC, USA
Hell, I was just going to cap everything for a few minutes and one-by-one reconnect everything so I can find out which hose/whatever is leaking by listening for a good increase in idle speeds. heh Thanks though.
------------------
89 iroc-z 305 tbi
k&n filtercharger, open element air filter. nuffin' else
------------------
89 iroc-z 305 tbi
k&n filtercharger, open element air filter. nuffin' else
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