Bad Fuel: Fact or Fiction? By Kunle Shonaike

Bad gasoline is not a myth. Fouled fuel found in a vehicle tank can usually be linked to a few suspects — it either came from the refinery, the distributor or the filling station down the street.

Refinery recalls

In the past, many drivers in Lagos and Nigeria as a whole faced hefty car repair bills after millions of gallons of contaminated fuel believed to cause engine problems.

Days following the incident, fuel suppliers were supposed to recall the bad fuel, but drivers had to pay to get the fuel out of their tanks.

According to a statement, the fuel contained “a higher than normal level of polymeric residue” which contaminated 50,000 barrels of regular unleaded fuel from the refinery. The fuel was shipped to several fuel stations in Nigeria, unbranded to many independent stations. As reported by local news outlets, scores of drivers began coming to repair shops reporting hard-starting and stalling engines, “check engine” lights, odd noises and other signs of engine trouble.

To remove the contaminated fuel out of a vehicle wasn’t as easy as just draining the fuel tank. Every part that the fuel touched between the tank and the engine had to be flushed and cleaned as well, since bad fuel had been known to ruin higher-pressure fuel injectors. Though not every car needed to be serviced — those who bought only a few gallons were able to dilute their bad gas by adding good fuel to the tank. Some fixes ranged from N100000 to N200000, while some owners said their repair bills topped N500000. Though fuel recalls are rare, they do occur. This topic shall continue.

Generic codes
P1103: MAP sensor high voltage

Meaning

The manifold absolute pressure sensor provides instantaneous manifold pressure information to the engine’s engine control module. The data is used to calculate air density and determine the engine’s air mass flow rate, which in turn determines the required fuel metering for optimum combustion. A fuel-injected engine may alternately use a mass air flow sensor to detect the intake airflow. A typical configuration employs one or the other, but seldom both. The MAP /BARO Switch solenoid valve switches it’s air flow passage according to the voltage signal sent from the ECM.

Possible causes

Faulty manifold absolute pressure
Manifold absolute pressure harness is open or shorted
Manifold absolute pressure circuit poor electrical connection
Faulty engine control module
P1104: MAP sensor low voltage

Meaning

The manifold absolute pressure sensor provides instantaneous manifold pressure information to the engine’s engine control module. The data is used to calculate air density and determine the engine’s air mass flow rate, which in turn determines the required fuel metering for optimum combustion. A fuel-injected engine may alternately use a mass air flow sensor to detect the intake airflow. A typical configuration employs one or the other, but seldom both. The MAP/BARO switch solenoid valve switches its air flow passage according to the voltage signal sent from the ECM.

Possible causes

Faulty manifold absolute pressure
Manifold absolute pressure harness is open or shorted
Manifold absolute pressure circuit poor electrical connection
Faulty engine control module
P1105: Manifold absolute pressure sensor malfunction

Meaning

The manifold absolute pressure sensor provides instantaneous manifold pressure information to the engine’s engine control module. The data is used to calculate air density and determine the engine’s air mass flow rate, which in turn determines the required fuel metering for optimum combustion. A fuel-injected engine may alternately use a mass air flow sensor to detect the intake airflow. A typical configuration employs one or the other, but seldom both. The MAP /BARO switch solenoid valve switches its air flow passage according to the voltage signal sent from the ECM.

Possible causes

Faulty manifold absolute pressure
Manifold absolute pressure harness is open or shorted
Manifold absolute pressure circuit poor electrical connection
Faulty engine control module
P1106: Barometric pressure sensor range/performance problem

Meaning

The barometric pressure (BARO) sensor is built into the engine control module and monitors atmospheric pressure. The ECM estimates appropriate intake airflow from the manifold absolute pressure sensor output voltage and BARO sensor output voltage. If the BARO sensor output voltage is a specified value or more, the ECM detects a malfunction and a code is stored.

Tech notes

Sometimes the P1106 is set when the engine control module can’t read the BARO sensor circuit. Before replacing any parts try performing the ECM reset procedure.

– Clear code

– Start the engine

– Hold the engine at 3,000 rpm with no load (in park or neutral) until the radiator fan comes on, then let it idle

– Test-drive with the A/T in 2nd position, M/T in fourth gear

– Press accelerator pedal over 1/2 way down for five seconds

– Check for codes again

– If the codes return, ECM may need to be replaced. If codes don’t return, the problem is repaired.

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Possible symptoms

Engine light on (or service engine soon warning light)
Engine rough idle
Engine hesitation
Possible causes

Engine control module outdated or incorrect software
Faulty engine control module
P1107: Barometric pressure sensor circuit low voltage

Meaning

The barometric pressure (BARO) sensor is built into the engine control module and monitors atmospheric pressure. The ECM estimates appropriate intake airflow from the manifold absolute pressure sensor output voltage and BARO sensor output voltage. If the BARO sensor output voltage is a specified value or more, the ECM detects a malfunction and a code is stored.

Possible symptoms

Engine light on (or service engine soon warning light)
Engine rough idle
Engine hesitation
Possible causes

Engine control module outdated or incorrect software
Faulty engine control module
P1108: Dual alternator battery lamp circuit malfunction

Meaning

The barometric pressure sensor is built into the engine control module and monitors atmospheric pressure. The ECM estimates appropriate intake airflow from the manifold absolute pressure sensor output voltage and BARO sensor output voltage. If the BARO sensor output voltage is a specified value or more, the ECM detects a malfunction and a code is stored.

Possible symptoms

Engine light on (or service engine soon warning light)
Engine rough idle
Engine hesitation
Possible causes

Engine control module outdated or incorrect software
Faulty engine control module
P1109: BARO sensor circuit out of range high

Meaning

The barometric pressure (BARO) sensor is built into the engine control module and monitors atmospheric pressure. The ECM estimates appropriate intake airflow from the manifold absolute pressure sensor output voltage and BARO sensor output voltage. If the BARO sensor output voltage is a specified value or more, the ECM detects a malfunction and a code is stored.

Possible symptoms

Engine light on (or service engine soon warning light)
Engine rough idle
Engine hesitation
Possible causes

Engine control module outdated or incorrect software
Faulty engine control module
P1110: Intake valve timing control bank 1

Meaning

This mechanism hydraulically controls cam phases continuously with the fixed operating angle of the intake valve.

The engine control module receives signals such as crankshaft position, camshaft position, engine speed, and engine coolant temperature. Then, the ECM sends ON/OFF pulse duty signals to the intake valve timing control solenoid valve depending on driving status. This makes it possible to control the shut/open timing of the intake valve to increase engine torque in low/mid speed range and output in high-speed range.

The intake valve timing control solenoid valve changes the oil amount and direction of flow through intake valve timing control unit or stops oil flow. The longer pulse width advances valve angle. The shorter pulse width retards valve angle. When ON and OFF pulse widths become equal, the solenoid valve stops oil pressure flow to fix the intake valve angle at the control position.

Possible symptoms

Engine light on (or service engine soon warning light)
Possible engine lack/loss of power
Possible engine rough idle
Possible causes

Faulty intake valve timing control solenoid valve
Intake valve timing control solenoid valve harness is open or shorted
Intake valve timing control solenoid valve may be faulty
Crankshaft position sensor may be faulty
Camshaft position sensor
FEEDBACK

May I ask your opinion about engine restore; my mechanic said my Mazda MPV is low on compression though not smoking. It’s having a hard start after change of plugs, coils and cleaning of injectors on March 3 because of hesitation. Only code is oxygen sensor 1&2. MAF cleaned last December.

My advice is for you to run a diagnosis scan on the engine and send the results of the scan to us for proper interpretation. I disagree with the mechanic’s diagnosis.

Punch

END

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