Question about 1998 Oldsmobile Silhouette

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The Vacuum line is not connected to the pressure control valve located on the engine block. Where does the vacuum line go to, so I can try to find it.

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Posted on Jan 02, 2017

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SOURCE: Vacuum Lines


Posted on Dec 12, 2008

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SOURCE: olds alero 2.4 idle fuel pressure

most likely idle air control sensor or low engine coolant I know sounds funny but IAC uses coolant to regulate idle. Idle air control valve or throttle body positioning sensor.

Posted on Feb 26, 2009

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SOURCE: I have an oldsmobile cutlass

Hi, one part is the solenoid and the other is a sensor (diagnostic switch). The vacuum supply from the carburetor goes to the solenoid, which has 2 ports. The other port goes to the EGR valve. There should be a "T" in that line with a hose running back to the sensor. The computer will turn on the solenoid when it's appropriate to pass exhaust gas back thru the intake. When the computer turns on the solenoid, the valve will open and the sensor will also detect the vacuum to let the computer know that the solenoid did indeed pass vacuum to the valve. I don't think it matters which port you plug the lines into on the solenoid, but the sensor must T off the line that goes to the valve. Please let me know if you have more questions, and thanks for using FixYa.

Posted on Jul 17, 2011

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How do i replace the heater control valve in a 1998 chev.c1500 v6 pu

The heater control valve is located on the passenger side rear of the engine. It has a vacuum line hose that opens and closes the valve. Remove the vacuum line hose, start the engine with the temperature set to cold and see if there is any vacuum on the line. Then set the temperature to the HOT position and see if there is any vacuum on the line. Vacuum should be present on ONE setting only. If nothing happens check for proper vacuum to the control assembly. The valve is vacuum operated, if no vacuum is present the valve won't work.


Feb 23, 2015 | Chevrolet Silverado 1500 Cars & Trucks

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Locate vacuum modulator chevy trailblazor 2003

Please verify the year of your truck. A 2003 Chevy Trailblazer has a 4L60E transmission. This transmission does not have a vacuum modulator valve. The 4L60 uses a vacuum modulator valve but the last year for that transmission was 1992. The perpose of the modulating valve is to control/regulate line pressure. The line pressure in a 4L60E is computer controlled or controlled electrically.

Dec 07, 2013 | Cars & Trucks

1 Answer


The Exhaust Gas Recirculation valve does just what the name implies: it diverts some exhau st gases back into the intake system at low engine speeds. This lowers combustion temperature to reduce NOx levels. It also reduces throttle response and bottom-end power.
Disabling the EGR valve is easy. Locate the valve and the EGR vacuum modulator valve (two gold-colored metal stampings, usually at the rear of the engine). The EGR valve has steel lines leading to it from the exhaust manifold. The EGR vacuum modulator has two vacuum lines between it and the intake manifold and a third vacuum (soft) line between the modulator and the EGR valve itself.
EGR Vacuum Modulator
EGR valve (arrow) is shown adjacent tosimilar EGR vacuum modulator valve. EGR valve is connected to exhaust manifold with steel lines. Modulator has vacuum lines only.
Disconnect the vacuum line between the valve and modulator and place any solid object of appropriate size (dowel, etc.) in the line, then reconnect the line. Or you can get a EGR block off plate

Oct 14, 2013 | Cars & Trucks

1 Answer

Heater valve location

It's a vacuum line to control the valve? It will connect there at valve and run into and under the dash to the back of the heater control panel. All the vacuum control hoses for the heat and AC are in a pod that connects to the back of the heater controls. A vacuum line from the engine is also there, the pod will send the vacuum signal out to various doors on the heater/AC case, as the controls demand. One also goes to the heater control valve.

Sep 09, 2013 | Cadillac Catera Cars & Trucks

1 Answer

Where are the purge lines to the purge valve diagram

Hello! Here is the diagram you requested...#5 is the Pressure Control Valve (Purge Valve)...
(1)Throttle Body (2)EVAP Solenoid Valve (3)EVAP Vacuum Switch (4)EVAP Canister (5)EVAP Pressure Control Valve (6)Floating Roll-Over Valve (7)Fuel Tank

Jan 01, 2012 | 1996 Buick Roadmaster

1 Answer

What is P 1491 in Nissan pathfinder 2003 and how to fix it



1. Confirm the Vacuum Cut Valve is installed correctly


^ The Vacuum Cut Valve will not work correctly and a DTC will be stored if it is installed upside-down.

^ The Vacuum Cut Valve is a white plastic valve near the fuel tank and EVAP canister.

2. Connect CONSULT-II and turn the ignition key to "N" (do not start the engine).


4. Note the EVAP System Pressure Sensor Voltage Confirm that it is reading in a normal range for a key ON arid engine OFF condition.

NOTE :For 2001 models and earlier:

^ Voltage in step 4 should be near 3.36 volts.

^ The normal range is between 3.32 - 3.40 volts.

For 2002 models:

^ Some 2002 models use a new type EVAP System Pressure Sensor with different operational characteristics.

^ Refer to the EC section of the appropriate Service Manual to determine which type sensor your vehicle is equipped with.

^ Models that use the new type EVAP System Pressure Sensor will have a voltage reading that varies with changes in the "barometric" pressure (atmospheric air pressure that changes with altitude and/or weather conditions).

^ The usual voltage range obtained in step 4 with the new type EVAP System Pressure Sensor is between 3.8 and 4.2 volts. Because this range will vary with barometric pressure, it is best to compare readings with a known good vehicle.

^ Some 2002 models use the earlier type EVAP System Pressure Sensor (same as used on 2001 and earlier models). The normal range for the earlier type is 3.32 to 3.40 volts and does not vary with barometric pressure.

5. Start the engine. Observe the EVAP System Pressure Sensor voltage.

^ If the value has reduced 0.04 volts or more from the reading obtained in step 4, the EVAP Canister Purge Volume Control Solenoid Valve may be leaking.

^ Refer to the EC section of the appropriate Service Manual for inspection procedures of the EVAP Canister Purge Volume Control Solenoid Valve, DTC P1444.

NOTE :The EVAP Canister Purge Volume Control Solenoid Valve is located in the engine compartment.

6. Perform the DTC Confirmation Procedure for DTC P1491. Refer to the EC section of the appropriate Service Manual for confirmation procedure steps and driving conditions.

7. If the DTC confirmation results are NG, do the following:

a. Refer to the EC section of the appropriate Service Manual to determine if the vehicle is equipped with On-Board Refueling Vapor Recovery (ORVR).

^ If the vehicle has ORVR, go to b.

^ If the vehicle does NOT have ORVR, go to step 8.

b. Place a clamp on the Refueling EVAP Vapor Line near the fuel tank. The Refueling EVAP Vapor Line is the larger hose (see figure 2). Use hose clamp (3M P/N # 08556-1), found in Fuel Injector Cleaning Kit J-45701, or equivalent.

c. Retry DTC Confirmation Procedure

d. If the result is now OK, the Refueling Control Valve may be leaking and should be inspected. Refer to the EC section of the appropriate Service Manual for Refueling Control Valve inspection procedures.

8. If the DTC confirmation is still NG after step 7, or the vehicle is not equipped with ORVR, do the following:

a. Disconnect two (2) lines from the Vacuum Cut Valve. One that goes to the fuel tank and one that goes to the EVAP Canister (see figure 1).

b. Use a hand vacuum pump to check each of the two (2) disconnected hoses for free flow. Make sure they are clear into the fuel tank (vent line) and into the EVAP Canister (see figure 2).


^ Figure 2 includes ORVR system. Refer to the appropriate service manual to determine if your vehicle has ORVR or not.

^ The lines between the Vacuum Cut Valve and Fuel Tank, and between the Vacuum Cut Valve and EVAP Canister may go through a metal line. Make sure the lines are clear between the Vacuum Cut Valve and Fuel Tank, and between the Vacuum Cut Valve and EVAP Canister, including any metal lines.

c. If any blockage is found, determine the cause and repair as necessary. Blockage in either of these lines will cause a DTC.

9. If all of the above checks do not locate the source of the incident, refer to the appropriate Service Manual for further DTC P1491 diagnosis.

Jun 29, 2011 | Nissan Pathfinder Cars & Trucks

1 Answer

I have ford f150 that i gave too my son that i need to change out the motor how hard is that ? It is a 4.2 it seem to hard getting people you can trust one they their going to do the work and the next day...

Hi, you will need an engine hoist to do this. The procedure also calls for removing the A/C refrigerant, which requires special equipment. I'm not sure this step is necessary, and I would try to avoid it. Other than that, you need a good set of standard tools. It is normally a couple days work, but with no experience, I would plan on a week to do the work. The procedure is listed below. This procedure does not account for any specific plans in terms of which parts of the old engine you plan to swap over. Those are additional steps. Please let me know if you have any questions, and thanks for uising FixYa.

4.2L Engine

CAUTION Fuel injection systems remain under pressure, even after the engine has been turned OFF. The fuel system pressure must be relieved before disconnecting any fuel lines. Failure to do so may result in fire and/or personal injury.
  1. Before servicing the vehicle, refer to the Precautions Section.
  2. Remove or disconnect the following:
    Both battery cables, negative cable first Hood Coolant Refrigerant, using approved equipment
  3. Relieve the fuel system pressure as follows:
    1. Remove the fuel tank fill cap to relieve the pressure in the fuel tank.
    2. Remove the cap from the fuel pressure relief valve located on the fuel injection supply manifold.
    3. Attach a fuel pressure gauge to the relief valve and drain the fuel through the drain tube into a suitable container.
    4. After the fuel system pressure is relieved, remove the fuel pressure gauge and install the cap on the relief valve. Secure the fuel tank fill cap.
  4. Remove or disconnect the following:
    Engine cooling fan, shroud and radiator Engine air cleaner outlet tube Accelerator and cruise control cables at the throttle body VMV hose Manifold vacuum connection Intake Manifold Runner Control (IMRC) vacuum connectors, fuel pressure regulator vacuum connector, IMRC solenoid vacuum connector and vacuum reservoir connector Exhaust Gas Recirculation (EGR) valve vacuum connector. The 3 power steering reservoir retaining bolts and position aside Air conditioning compressor manifold bolt and disconnect, then position the air conditioning lines aside. The 4 power steering pump retaining bolts and position the pump aside. Alternator electrical harness connectors. Remove the positive battery cable nut and disconnect the battery cable. Electrical harness connectors to the fuel injectors Wires at the spark plugs Both heater hoses Brake booster vacuum hose EGR Differential Pressure Feedback (DPFE) transducer hose Breather tube from the cylinder head cover Upper intake manifold Fuel supply and return lines, and remove the fuel injection supply manifold. Block heater cable Exhaust system from the exhaust manifolds and support with wire hung from the crossmember. Starter motor Transmission from the vehicle. If equipped with a manual transmission, remove the clutch assembly. Right-hand and left-hand engine support insulator through-bolts
  5. Install a suitable engine lifting bracket and connect suitable engine lifting equipment to the lifting brackets.
  6. Carefully raise the engine out of the engine compartment and position on a work stand. Remove the engine lifting equipment.
To install:
  1. Install the engine lifting brackets. Support the engine using a suitable floor crane installed to the lifting equipment and remove the engine from the work stand.
  2. Carefully lower the engine into the engine compartment aligning the engine support insulators.
  3. Remove the engine lifting equipment and brackets.
  4. Raise and safely support the vehicle.
  5. Install or connect the following:
    NOTE Ensure that the air conditioning manifold O-rings are in place.
    Left-hand and right-hand engine support insulator through-bolts and tighten them to 51-67 ft. lbs. (68-92 Nm). Transmission, and the clutch assembly Starter motor Exhaust pipes to the exhaust manifolds and tighten to 30 ft. lbs. (41 Nm). Block heater Heater cable Alternator electrical harness connectors and install the positive battery cable to the retaining stud. Tightenthe retaining nut to 96 inch lbs. (11 Nm). Fuel injectors and the fuel injection supply manifold New upper intake gasket and install the upper intake manifold. Electrical harness connectors to the fuel injectors Power steering pump in position and install 4 retaining bolts. Tighten the bolts to 17-20 ft. lbs. (22-28 Nm). Air conditioning manifold to the compressor and install the retaining bolt. Tighten the bolt to 14-18 ft. lbs. (18-24 Nm). Power steering reservoir and 3 retaining bolts. Tighten the bolts to 107 inch lbs. (12 Nm). VMV hose IMRC vacuum connectors, fuel pressure regulator vacuum connector, IMRC solenoid vacuum connector and vacuum reservoir connector. EGR valve vacuum connector Brake booster hose The 2 EGR DPFE transducer hoses Manifold vacuum connection Accelerator cable and speed control cable in position, if equipped. Tighten the speed control cable retaining bolt to 72 inch lbs. (8 Nm) and accelerator cable retaining bolt to 25 inch lbs. (3 Nm). Radiator, cooling fan and shroud Engine air cleaner outlet tube Engine oil Coolant; bleed the system Battery cables, negative cable last
  6. Start the engine and allow to reach normal operating temperature while checking for leaks.
  7. Check all fluid levels.
  8. Properly evacuate and recharge the air conditioning system using approved equipment.
  9. Install the hood, aligning the marks that were made during removal.
  10. Road test the vehicle and check the engine and transmission for proper operation.

Mar 12, 2011 | 2001 Ford F150 Styleside SuperCrew

2 Answers

Codigo p1440

EVAP System Vent Circuit Malfunction

This diagnosis detects leaks in the Evaporative Emission (EVAP) purge line using of vapor pressure in the fuel tank. The EVAP canister vent control valve is closed to shut the EVAP purge line. The vacuum cut valve bypass valve will then be opened to clear the line between the fuel tank and the EVAP canister purge volume control solenoid valve. The EVAP control system pressure sensor can now monitor the pressure inside the fuel tank. If pressure increases, the Engine Control Module (ECM) will check for leaks in the line between the vacuum cut valve and EVAP canister purge volume control solenoid valve.

Possible causes
- Incorrect fuel tank vacuum relief valve
- Incorrect fuel filler cap used
- Fuel filler cap remains open or fails to close
- Foreign matter caught in fuel filler cap
- Leak is in line between intake manifold and EVAP canister purge volume control solenoid valve
- Foreign matter caught in EVAP canister vent control valve
- EVAP canister or fuel tank leaks
- EVAP purge line (pipe and rubber tube) leaks
- EVAP purge line rubber tube bent
- Blocked or bent rubber tube to EVAP control system pressure sensor
- Loose or disconnected rubber tube
- EVAP canister vent control valve and the circuit
- O-ring of EVAP canister vent control valve is missing or damaged
- EVAP canister is saturated with water
- EVAP control system pressure sensor
- Absolute pressure sensor

Possible solution
- Loose fuel filler cap
- Leaking fuel filler cap

Hope helps (remember to rate this answer).

Jan 05, 2011 | 2000 Hyundai Sonata

1 Answer

Hi I have a 98 gmc sierra 1500 with 5.7 vortec, recently replaced gas tank and fuel pump engine light came on had obd code po442 change gas line to evap canister to high pressure fuel line light went off,...

It's hard to find these small leaks. If you have a vacuum pump, there are a few tests you can run on the components of the system. See below.


Vapor Canister
See Figure 1

  1. Apply a length of hose to the lower tube of the purge valve assembly and attempt to blow air through it. There should be little or no air should passing into the canister.

If the canister is equipped with a constant purge hole, a small amount of air will pass into the canister.
  1. Using a hand-held vacuum pump, apply a vacuum of 15 in. Hg (51 kPa) to the control vacuum (upper) tube. If the vacuum does not hold for at least 20 seconds, the diaphragm is leaking. Replace the canister.
  2. If the diaphragm holds vacuum, attempt to blow air through the hose connected to the PCV tube while vacuum is still being applied. An increase of air should be observed. If no increase is noted, the canister must be replaced.

Fig. Fig. 1: Cross-section of the vapor canister

Fuel Tank Pressure Control Valve

  1. Attach a length of hose to the tank side of the valve assembly and try to blow air through it. Little or no air should pass into the canister.
  2. Using a hand-held vacuum pump, apply vacuum equivalent to 15 in. Hg (51 kPa) to the control vacuum tube. If the diaphragm does not hold vacuum, the diaphragm is leaking. Replace the valve.
  3. If the diaphragm holds vacuum, attempt to blow air through the hose connected to the valve while vacuum is still being applied. Air should pass. If no air is noted, the valve must be replaced.

Thermostatic Vacuum Switch
  1. With engine temperature below 100°F (38°C), apply vacuum to the manifold side of the switch. The switch should hold vacuum.
  2. Start and continue to run the engine until the engine temperature increases above 122°F (50°C). The vacuum should drop off.
  3. Replace the switch if it fails either test.

purge valve location:


EVAP vacuum switch pic:


EVAP system diagram:

Nov 20, 2010 | GMC Sierra 1500 Cars & Trucks

2 Answers

Dtc p1550 1999 vw tdi intermittent poor power.

For VW TDI: Fault code P1550 = "Charge Pressure Deviation"
You must check up all vacuum hoses, the pressure charge air line (pressure hoses, spring-type clips, charge air cooler), the vacuum reservoir and also all solenoid control valves.
You must try follows if you are able to do this:
1. Engine stopped and ignition switch off. Check all pneumatic connections and hoses between turbocharger actuator = pressure unit for boost-pressure control, boost-pressure control solenoid valve, vacuum reservoir, EGR control solenoid valve, intake-manifold flap solenoid valve, EGR valve with throttle - part of intake manifold. Also the vacuum connection between tandem pump and brake booster. If you find something wrong replace parts. If not go to step 2.
2. Extract the hose of the turbocharger actuator = pressure unit for boost-pressure control part of turbocharger. Instead of the original hose you must place another 1 meter long hose with the same inside diameter, and then you check to inspire yourself the air from the other one extremity of this hose. The mechanical connecting rod of the turbocharger actuator must have a smooth and whole motion. If you can do that with your mouth, then you must replace the boost-pressure control solenoid valve. If you can not reach this with your mouth, then you go to step 3.
3. This is the most difficult work. The problem is that the soot particles deposits inside the turbocharger plugging the variable nozzle geometry mechanism = adjustable vanes of the turbine. If the turbocharger actuator is not able to adjust the turbine vanes the charge air pressure increase too much and ECU (engine control unit) go in "limp mode" = engine protection software. As a result the "limp mode" engine still running until you turn the engine off (ignition switch off) and back on when the "limp mode" is deactivated.
4. You must be able to extract the turbo from the engine and then to disassemble the turbocharger, clean inside adjustable vanes mechanism and refit all.
It is some work to do here, but after that you will be full satisfied!

Jun 30, 2009 | 2000 Volkswagen Jetta TDI

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