1991 Chevy c/k 2500 5.7l MAP sensor-engine management? Can anyone tell me where on the top of the engine or manifold the MAP bracket attaches? I know it goes on right side (passenger) but where in relation to the throttle body, EGR and distributor does it fit? Is the bolt that holds the bracket 5/16" and is the manifold tapped somewhere? Where does the vacuum line from the MAP go to? Throttle body? Which port? I should have taken Photo’s! Thank You for any help.

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It is the MAP (manifold absolute pressure) sensor.

How to Tell if You Have a Bad MAP Sensor

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Apr 6, 2018 - The MAP sensor reads the pressure in the intake manifold and transmits this data to the engine's computer. If it fails, your engine will run ...
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Map sensor is attached to the intake manifold. Rectangular sensor with an electrical plug on it.

Under hood, center, rear engine area, above valve cover, mounted in bracket.

From autozone.com:

Manifold Air Pressure Sensor

Fig. MAP sensor specifications-note how altitude and pressure affect the voltage readings
REMOVAL & INSTALLATION

1. Remove the intake manifold top cover.
2. Disconnect the crankcase breather tube from the throttle body.
3. Remove the MAP sensor from the intake manifold.
4. Detach the MAP sensor electrical connector.
5. Inspect the MAP sensor grommet for wear or damage and replace as needed.

To install:

1. Installation is the reversal of the removal procedure.

1996 Chevrolet Truck G10 1/2 ton Van 5.0L SFI 8cyl

The MAP Sensor is located: Front seating area, center, under engine cover, rear passenger side of intake manifold, above valve cover, mounted on bracket.Here's a link to what it look's like Brad. MAP Sensor at AutoZone com Best MAP Sensor Parts for Cars Trucks SUVS

as it is the basic 305 block the differences may be fuel injection over carburettor which may require sensor attachments but basically the engine should just slot in place.

consult the owners manual or shop manual for that vehicle

Manifold Absolute Pressure Sensor

• OPERATION
• TESTING
• REMOVAL & INSTALLATION

Print

OPERATION

See Figures 1, 2 and 3

Fig. Fig. 1: MAP sensor location-2.4L engine

Fig. Fig. 2: MAP sensor location-3.0L engine

Fig. Fig. 3: MAP sensor location-3.3L and 3.8L engines
The PCM supplies 5 volts of direct current to the Manifold Absolute Pressure (MAP) sensor. The MAP sensor then converts the intake manifold pressure into voltage. The PCM monitors the MAP sensor output voltage. As vacuum increases, the MAP sensor voltage decreases proportionately. Also, as vacuum decreases, the MAP sensor voltage increases proportionally.
With the ignition key ON , before the engine is started, the PCM determines atmospheric air pressure from the MAP sensor voltage. While the engine operates, the PCM figures out intake manifold pressure from the MAP sensor voltage. Based on the MAP sensor voltage and inputs from other sensors, the PCM adjusts spark advance and the air/fuel ratio. The MAP sensor is mounted to the intake manifold, near the throttle body inlet to the manifold. The sensor connects electrically to the PCM.

TESTING

See Figures 4, 5, 6 and 7

Fig. Fig. 4: Disengage the MAP sensor connector-3.0L engine shown

WARNING When testing the MAP sensor, make sure the harness wires do not become damaged by the test meter probes.

1. Visually check the connector, making sure it is attached properly and that all of the terminals are straight, tight and free of corrosion.

Fig. Fig. 5: MAP sensor connector terminal identifications: (A) 5-volt supply, (B) sensor signal, (C) ground-3.0L engine shown

Fig. Fig. 6: MAP sensor connector terminal identifications-2.4L, 3.3L and 3.8L engines

Fig. Fig. 7: Using a digital volt-ohmmeter, test the MAP sensor voltage-3.0L engine shown

1. Test the MAP sensor output voltage at the sensor connector between terminals B and C (2.4L, 3.3L and 3.8L engines), or A nd B (3.0L engine).
2. With the ignition switch ON and the engine not running, the output voltage should be 4-5 volts. The voltage should fall to 1.5-2.1 volts with a hot, neutral idle speed condition. If OK, go to the next step. If not OK, go to Step 5.
3. Test the PCM terminal 36 for the same voltage described in the previous step to make sure the wire harness is OK. Repair as necessary.
4. Test the MAP sensor ground circuit at the sensor connector terminal A (2.4L, 3.3L and 3.8L engines) or C (3.0L engine) and PCM terminal 43. If OK, go to the next step. If not OK, repair as necessary.
5. Test the MAP sensor supply voltage between the sensor connector terminals A and B (2.4L, 3.3L and 3.8L engines) r A and C (3.0L engine) with the ignition key in the ON position. The voltage should be about 4.5-5.5 volts.
6. There should also be 4.5-5.5 volts at terminal 61 of the PCM. If OK, replace the MAP sensor.
7. If not, repair or replace the wire harness as required.

REMOVAL & INSTALLATION

See Figures 1, 2, 3 and 4
The MAP sensor is mounted on the intake manifold near the throttle body inlet to the manifold.

1. Disconnect the negative battery cable.
2. On the 3.0L engine only, disconnect the vacuum hose from the MAP sensor.
3. Detach the electrical connector from the MAP sensor.
4. Unfasten the mounting screws, then remove the MAP sensor from the vehicle.

To install:

1. Install the sensor onto the intake manifold and tighten the mounting screws to 35 inch lbs. (4 Nm).
2. Attach the sensor electrical connector.
3. On the 3.0L engine, connect the vacuum hose to the MAP sensor.
4. Connect the negative battery cable.

If there is a 'vacuum leak', then a hose may be leaking or disconnected from a device such as the EGR valve (on older engines), for instance. Or, it could be a loose or leaking MAP sensor gasket:


Manifold Absolute Pressure (MAP) Sensor Removal & Installation 3.5L & 3.9L Engines To Remove:
MAP sensor (typical)

1. Remove the engine cover.
2. Disconnect the MAP sensor electrical connector.
3. Remove the MAP sensor mounting bolts from the intake manifold and remove the MAP sensor with the retainer bracket and seal.

To Install:

1. Install the MAP sensor with the retainer bracket and seal to the intake manifold. Tighten the mounting bolts 18 ft-lb (25 Nm).
2. Connect the MAP sensor electrical connector.

5.3L Engine To Remove:

1. Remove the engine cover.
2. Disconnect the manifold absolute pressure sensor (MAP) harness connector. MAP sensor (typical 5.3L)
   
   
3. Remove the MAP sensor from the intake manifold.

To Install:

1. Apply clean engine oil to the MAP sensor inlet tube.
2. Install the MAP sensor on the intake manifold.
3. Connect the MAP sensor harness connector.
4. Install the engine cover.

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May want to purchase a Haynes or Chilton manual and study the vacuum line diagram to see if you can determine if one of the vacuum hoses is loose or misplaced or broken.

One can also do a visual inspection of the hoses to see if any are disconnected from where they should be.

REMOVAL & INSTALLATION

1. Disconnect the negative battery cable.
2. Locate the MAP sensor and remove the retaining screws
3. Detach the electrical connector.

Fig. On the 3.1L engine, the MAP sensor is located alongside the intake manifold



Fig. MAP sensor and its bracket arrangement-3.4L (VIN E) engine



Fig. Location of the MAP sensor on the throttle body adapter-3.4L (VIN X) Engine



Fig. The MAP sensor is located just behind the throttle body mounting base-3.5L (VIN H) engine



Fig. MAP sensor and its location alongside the supercharger-3.8L (VIN 1) Engine



Fig. On the 3.8L (VIN K) engine, the MAP sensor is located on top of the PCV valve cover

1. Remove the vacuum hose and lift the MAP sensor from the engine.
2. Installation is reverse of the removal procedure.

Hope helps (remember rated and comment this).

P0105 is MAP (Manifold Absolute Pressure) or BARO (Barometric pressure) circuit malfunction