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MAP sensor fail

Fuel economy is down

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O2 sensor check and catalytic converter check for contamination

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SOURCE: trouble shoot low fuel economy

try any of the following::::new spark plugs, fuel injecter clean(if it has any), using cruise control on long flat roads,new fuel filter, new after market air filter, pcv valve helps a little.. very easy to change to.......thats all i can think of..

Posted on Jul 20, 2010

Testimonial: "I'll check plug gaps (?) and double check the dates of my fuel filter and air filter. I keep the box tab with the date and mileage on them. Could an EGR also be a problem. The engine has no signs if trouble but just seems not 100%. Thanks for the help, John"

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MAP sensor vehicle v6 motor 1992

What is the question? A manifold absolute pressure sensor is a measure of intake manifold vacuum. The sensor sends a varying voltage signal to the computer based on the actual pressure, or vacuum, in the intake manifold. The pcm uses the signal to help compute amount of fuel required for the given conditions . If engine is accelerated, it has a load on it-vacuum is momentarily reduced. The pcm senses this load and knows to add more fuel.

MAP sensors been around a long time-ever since the onset of fuel injection during the 1980's. The auto giants had to be dragged kicking and screaming into new technology. I have a '92 Buick with a MAF sensor (mass air flow) and no MAP sensor. But my son owns a 2005 Buick century with both a MAF and a MAP sensor. I guess they are getting more sophisticated, more precise in fuel economy. Heaven knows, we need that, given our guzzling habits, appetites, and indulgences. I have been accused of moralizing too much, so I am responding with vigor!

Dec 05, 2014 | Holden VT Cars & Trucks

2 Answers

What is the function of map sensor


Jun 08, 2013 | 1992 GMC Sierra

1 Answer

P0107 gm code

What does that mean?

The Manifold Absolute Pressure (MAP) sensor responds to changes in the intake manifold pressure (vacuum). 5 Volts is supplied to the sensor from the PCM (powertrain control module). Inside the MAP sensor is a resistor that moves in relation to manifold pressure. The resistor varies the voltage between about 1 volt to 4.5 volts (depending on engine load) and that voltage signal is returned to the PCM to indicate manifold pressure (vacuum). This signal is essential for the PCM to determine fuel delivery. A P0107 DTC is set when the PCM sees that the MAP signal voltage is less than .25 volts which is too low.
FB.init("dd7d9e9681341cde77587bc6a2029f6f"); on Facebook Potential Symptoms

Anytime the MAP sensor signal is low the vehicle will likely have a very difficult time starting. Other symptoms may include:

  • Hard to start
  • Long cranking times
  • Sputtering/missing
  • Blowing black smoke
  • Poor fuel economy
  • Dies intermittently
  • MIL(Malfunction Indicator Lamp) illumination

The causes of a low MAP sensor signal circuit (P0107) could be any of the following:

  • Bad MAP sensor
  • Open or short in the signal circuit
  • Open or short in the 5 Volt reference circuit
  • Ground circuit open or shorted
  • Bad PCM

Jun 22, 2012 | 2008 Pontiac G6

1 Answer

Why my prado smoke black too much

Black smoke always indicates that there is problem with the air/fuel mixture. This would have an great impact on the fuel economy.The possible faulty parts can be MAP sensor or the TPS or the O2 sensor could be bad too. There are just too many things that it could be.

Mar 17, 2011 | 1999 Toyota Land Cruiser

1 Answer

Check engine light comes on . read out says map sensor. what is map sensor and what is its job. and how long to let it go

the MAP sensor ( manifold absolute pressure ) the sensor monitors the engine vacuum, as the vacuum decreases like when you accelerate or are pulling a load like climbing a large hill. the on-board computer uses this info. and other info. from other sensors like the TPS and MASS to make adjustments to the fuel mixture and ignition timing to give you the most power and fuel economy. the computer will use other info. if it thinks the MAP is not giving correct readings but with out this sensor the fuel mileage and power will be reduced, you need to have it repaired soon, it most likely will not cause the car to stop running but it will not run properly with out the sensor. also the car will not pass a state emission test with the light on and the sensor not working.

Mar 15, 2011 | 2004 GMC Envoy

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Hard to start running rich & stall

Sounds like a MAP inlet Manifold Absolute Pressure sensor fault. Symptoms of a faulty MAP

  • Poor starting/erratic idling/engine stall - with the MAP not sending the correct inlet air pressure signals to the ECU, incorrect fuel injection volumes then result. The imbalance in the fuel/air ratio often leads to rough engine performance and poor starting and stall. The engine might be kept running at start up by pumping the accelerator pedal
  • Sluggish performance/power ceiling - the engine may seem to perform normally in the lower rev range but will severely run out of power above about 3000 rpm
Poor fuel economy. The ECU tends to supply an over rich fuel mix to the engine in the absence of signal from the MAP resulting in very poor fuel economy. The reason for this is that if the MAP has no signal this ECU assumes 'no vacuum' = fully open throttle = engine is under load. To match this 'open throttle' signal the ECU increases the injection cycle to supply more fuel

How to Check? The MAP has three electrical pins, one for 12 volts (or 5 volts) reference, one for ground and the third (the middle one generally) is the 'signal' output. Put a voltmeter positive connector on the 'signal' pin of the connected socket (back probe by inserting a bit of wire). Apply suction to the vacuum input, even sucking on it with your mouth, should result in a measurable voltage output. At normal air pressure (open throttle) the voltage seen should be 0 volts. As vacuum is applied the voltage output should change to about 5 volts (throttle closed at idle). If no transition seen the MAP is faulty.

Feb 02, 2011 | Chrysler Sebring Cars & Trucks

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I have a 1998 Sonoma truck which after the engine warms up and I get to 20 mph, the rpm gauge shows 3000 rpm, but the engine has no power. It burns a lot of fuel. What do you think is my problem?

If you can have the codes read from the on-board diagnostics, Autozone do this for free. This should indicate the system at fault. In the absence of a code your symptoms indicate a faulty MAP (manifold absolute air pressure) sensor. THe MAP sensor has a three wire plug to it. You will need a volt meter. The outer pins are reference 0 volts and 5 volts. The middle pin is signal output to the ECU it should be about 1.3 volts at idle. If the MAP fails ie no signal then the ECU reads this as 'LOW VACUUM' and assumes the engine is under load (throttle fully open - hence no inlet vacuum) it responds by increasing injection times and this leads to bad fuel economy and a lumpy unresponsive engine (always too much fuel and not enough air) After these checks visit a breakers yard and source a replacement MAP sensor (should be less than $5) and fit it. If this fixes the problem you may wish to consider buying a new one ($25 on ebay), but if money is tight (when isnt it?) run it until the symptoms again appear again i.e. the recycled replacement is dead.

Sep 25, 2010 | 1998 GMC Sonoma

2 Answers

I have a 1994 chevy work truck with a 305. I have trouble codes # 15, 22, 33, 34, 44, and 53. The egr valve had been removed but apeared good. Someone had put a plate over the port. Additionaly someone...

DTC - 15 Engine coolant temp sensor error (low temp indicated)
DTC - 22 Throttle position sensor error (signal low)
DTC - 33 MAP sensor circuit error (signal high indicating low vacuum)
DTC - 34 MAP sensor circuit error (signal low indicating high vacuum)
DTC - 44 Oxygen sensor error (lean condition indicated)
DTC - 53 Digital EGR Valve solenoid 1 error

MAP is short for manifold absolute pressure sensor,,it senses the manifold pressure and applies the right amount of gas with the right amount of ignition timing so the car runs and performs well if this does not work properly,it throws off the whole loop cycle for the computer,,which in turn makes it run badly,,and get poor fuel economy,,it causes one to have a lack of power,,combined with a loss of fuel economy,,and also poor take offs,,and sometimes an occasional stalling,,i hope this helps.

EGR system was really developed for was emissions control. the purpose of the EGR valve is to regulate the amount of exhaust gas recirculated back into your combustion chamber to send the gasses through another cycle in order to eliminate any excess pollutants like NOX (nitrogen oxides), N2 (nitrogen), O2 (oxygen), CO2(carbon dioxide) and HC (Hydrocarbons). the EGR was also developed to lower combustion temps that's another reason why the exhaust is recirculated the exhaust gasses will not burn therefor lowering combustion temps, because there is less "usable" air going into the cylinders.

Nov 17, 2009 | 1994 Chevrolet C/K 2500

1 Answer

What does trouble code P0171 for a 2002 Buick Park Avenue mean?

Trouble Code: P0171 (3.8L V6 VIN 1 Auto)
Fuel Trim System Lean (Bank 1) Print this code dataprint_icon_codes.gif Number of Trips to Set Code: 2
OBD II Monitor Type: CCM Details
Indicators: MIL Details
Trouble Code Conditions:
DTC P0101-P0103, P0107, P0108, P0121-P0123, P0130-P0138, P0140, P0141, P0201-P0206, P0300, P0401-P0405, P0410, P0440-P0446, P0506, P0507, P1404 or P1441 not set, engine started, vehicle driven at less than 82 mph at 550-4000 rpm, BARO sensor over 70 kPa (10.1 psi), ECT sensor from 68-230ºF, IAT sensor from 64-158ºF, MAF sensor from 2.8-150 gm/s, MAP sensor from 16-105 kPa (2.6-15.2 psi), fuel level over 10%, and the PCM detected the Long Term fuel trim value was more than +20% for 6 seconds. The PCM controls the air/fuel metering system to good overall fuel economy, driveability, and emission control. During open loop, the PCM determines fuel delivery based on sensor signals, without the oxygen sensor input. During closed loop, the PCM adds oxygen sensor inputs to calculate Short and Long term fuel trim fuel delivery adjustments. Short Term fuel trim values change rapidly in response to changes in the oxygen sensor signals. Long Term fuel trim makes coarse adjustments in order to maintain an air/fuel ratio of 14.7:1.

Possible Causes:
  • Air leaks in intake manifold, exhaust pipes or exhaust manifold
  • Fuel control sensor is out of calibration (ECT, IAT or MAF)
  • Low fuel pressure (fuel filter clogged, pressure regulator failure)
  • One or more injectors restricted or pressure regulator has failed
  • HO2S element is contaminated, deteriorated or has failed
  • Vacuum hose is disconnected, broken, leaking or loose

Troubleshooting:2002 Buick Park Avenue, 3.8L, P0171

Nov 01, 2009 | 2002 Buick Park Avenue

1 Answer


Won't usually prevent from starting, but can. Definitely creates a number of driveability issues including hard starting, rough idle, stalling, buck/surge while driving, and poor fuel economy.

Jun 26, 2009 | 1994 Cadillac DeVille

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