Question about 1990 Toyota 4Runner

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1990 4Runner, 3.0L engine, fuel pump pressure test?

Should the fuel pump produce a flow with the ignition switch in the on position or only when cranking engine ?

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The pump should be running and producing fuel when ignition switch is in the on position.

Posted on Jun 03, 2010

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2000 Taurus SE station wagon fuel pump how do I know if it's working when I bleed the valve underneath the hood should it a constant spurt not a constant flow or just aspart went the ignition on


The PCM - engine computer will energize the fuel pump relay for two seconds with the key , When cranking the engine the PCM will only energize the fuel pump relay if a crankshaft position input is seen . An testing fuel pump pressure should be done with a fuel pump pressure gauge only .

Feb 19, 2017 | 2000 Ford Taurus

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Ford OBD-II Trouble Codes


P1000 OBD-II Monitor Testing Incomplete<br />P1001 KOER Test Cannot Be Completed<br />P1039 Vehicle Speed Signal Missing or Improper<br />P1051 Brake Switch Signal Missing or Improper<br />P1100 Mass Air Flow Sensor Intermittent<br />P1101 Mass Air Flow Sensor out of Self-Test Range<br />P1112 Intake Air Temperature Sensor Intermittent<br />P1116 Engine Coolant Temperature Sensor is out of Self-Test Range<br />P1117 Engine Coolant Temperature Sensor Intermittent<br />P1120 Throttle Position Sensor out of range<br />P1121 Throttle Position Sensor Inconsistent with Mass Air Flow Sensor<br />P1124 Throttle Position Sensor out of Self-Test Range<br />P1125 Throttle Position Sensor Intermittent<br />P1127 Heated Oxygen Sensor Heater not on During KOER Test<br />P1128 Heated Oxygen Sensor Signals reversed<br />P1129 Heated Oxygen Sensor Signals reversed<br />P1130 Lack of Upstream Heated Oxygen Sensor Switch - Adaptive Fuel Limit - Bank No. 1<br />P1131 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 1<br />P1132 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Rich - Bank No. 1<br />P1135 Ignition Switch Signal Missing or Improper<br />P1137 Lack of Downstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 1<br />P1138 Lack of Downstream Heated Oxygen Sensor Switch - Sensor Indicates Rich - Bank No. 1<br />P1150 Lack of Upstream Heated Oxygen Sensor Switch - Adaptive Fuel Limit - Bank No. 2<br />P1151 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 2<br />P1152 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Rich - Bank No. 2<br />P1157 Lack of Downstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 2<br />P1158 Lack of Downstream Heated Oxygen Sensor Switch - Sensor Indicates Rich - Bank No. 2<br />P1220 Series Throttle Control fault<br />P1224 Throttle Position Sensor B out of Self-Test Range<br />P1230 Open Power to Fuel Pump circuit<br />P1231 High Speed Fuel Pump Relay activated<br />P1232 Low Speed Fuel Pump Primary circuit failure<br />P1233 Fuel Pump Driver Module off-line<br />P1234 Fuel Pump Driver Module off-line<br />P1235 Fuel Pump Control out of range<br />P1236 Fuel Pump Control out of range<br />P1237 Fuel Pump Secondary circuit fault<br />P1238 Fuel Pump Secondary circuit fault<br />P1250 Lack of Power to FPRC Solenoid<br />P1260 Theft Detected - Engine Disabled<br />P1270 Engine RPM or Vehicle Speed Limiter Reached<br />P1288 Cylinder Head Temperature Sensor out of Self-Test Range<br />P1289 Cylinder Head Temperature Sensor Signal Greater Than Self-Test Range<br />P1290 Cylinder Head Temperature Sensor Signal Less Than Self-Test Range<br />P1299 Cylinder Head Temperature Sensor Detected Engine Overheating Condition<br />P1309 Misfire Detection Monitor not enabled<br />P1351 Ignition Diagnostic Monitor circuit Input fault<br />P1352 Ignition Coil A - Primary circuit fault<br />P1353 Ignition Coil B - Primary circuit fault<br />P1354 Ignition Coil C - Primary circuit fault<br />P1355 Ignition Coil D - Primary circuit fault<br />P1356 Loss of Ignition Diagnostic Module Input to PCM<br />P1358 Ignition Diagnostic Monitor Signal out of Self-Test Range<br />P1359 Spark Output circuit fault<br />P1364 Ignition Coil Primary circuit fault<br />P1380 VCT Solenoid Valve circuit Short or Open<br />P1381 Cam Timing Advance is excessive<br />P1383 Cam Timing Advance is excessive<br />P1390 Octane Adjust out of Self-Test Range<br />P1400 Differential Pressure Feedback Electronic Sensor circuit Low Voltage<br />P1401 Differential Pressure Feedback Electronic Sensor circuit High Voltage<br />P1403 Differential Pressure Feedback Electronic Sensor Hoses Reversed<br />P1405 Differential Pressure Feedback Electronic Sensor circuit Upstream Hose<br />P1406 Differential Pressure Feedback Electronic Sensor circuit Downstream Hose<br />P1407 EGR No Flow Detected<br />P1408 EGR Flow out of Self-Test Range<br />P1409? EGR Vacuum Regulator circuit malfunction<br />P1409? Electronic Vacuum Regulator Control circuit fault<br />P1410 EGR Barometric Pressure Sensor VREF Voltage<br />P1411 Secondary Air is not being diverted<br />P1413 Secondary Air Injection System Monitor circuit Low Voltage<br />P1414 Secondary Air Injection System Monitor circuit High Voltage<br />P1442 Secondary Air Injection System Monitor circuit High Voltage<br />P1443 Evaporative Emission Control System - Vacuum System - Purge Control Solenoid or Purge Control Valve fault<br />P1444 Purge Flow Sensor circuit Input Low<br />P1445 Purge Flow Sensor circuit Input High<br />P1450 Inability of Evaporative Emission Control System to Bleed Fuel Tank<br />P1451 EVAP Control System Canister Vent Solenoid Circuit Malfunction<br />P1452 Inability of Evaporative Emission Control System to Bleed Fuel Tank<br />P1455 Substantial Leak or Blockage in Evaporative Emission Control System<br />P1460 Wide Open Throttle Air Conditioning Cutoff circuit malfunction<br />P1461 Air Conditioning Pressure Sensor circuit Low Input<br />P1462 Air Conditioning Pressure Sensor circuit high Input<br />P1463 Air Conditioning Pressure Sensor Insufficient Pressure change<br />P1464 ACCS to PCM High During Self-Test<br />P1469 Low Air Conditioning Cycling Period<br />P1473 Fan Secondary High with Fans Off<br />P1474 Low Fan Control Primary circuit<br />P1479 High Fan Control Primary circuit<br />P1480 Fan Secondary Low with Low Fans On<br />P1481 Fan Secondary Low with High Fans On<br />P1483 Power to Cooling Fan Exceeded Normal Draw<br />P1484 Variable Load Control Module Pin 1 Open<br />P1500 Vehicle Speed Sensor Intermittent<br />P1501 Programmable Speedometer & Odometer Module/Vehicle Speed Sensor Intermittent circuit-failure<br />P1502 Invalid or Missing Vehicle Speed Message or Brake Data<br />P1504 Intake Air Control circuit malfunction<br />P1505 Idle Air Control System at Adaptive Clip<br />P1506 Idle Air Control Over Speed Error<br />P1507 Idle Air Control Under Speed Error<br />P1512 Intake Manifold Runner Control Stuck Closed<br />P1513 Intake Manifold Runner Control Stuck Closed<br />P1516 Intake Manifold Runner Control Input Error<br />P1517 Intake Manifold Runner Control Input Error<br />P1518 Intake Manifold Runner Control fault - Stuck Open<br />P1519? Intake Manifold Runner Control Stuck Open<br />P1520? Intake Manifold Runner Control circuit fault<br />P1519? Intake Manifold Runner Control fault - Stuck Closed<br />P1520? Intake Manifold Runner Control fault<br />P1530 Open or Short to A/C Compressor Clutch circuit<br />P1537 Intake Manifold Runner Control Stuck Open<br />P1538 Intake Manifold Runner Control Stuck Open<br />P1539 Power to A/C Compressor Clutch circuit Exceeded Normal Current Draw<br />P1549 Intake Manifold Temperature Valve Vacuum Actuator Connection<br />P1550 Power Steering Pressure Sensor out of Self-Test Range<br />P1605 PCM Keep Alive Memory Test Error<br />P1625 Voltage to Vehicle Load Control Module Fan circuit not detected<br />P1626 Voltage to Vehicle Load Control Module circuit not detected<br />P1650 Power Steering Pressure Switch out of Self-Test Range<br />P1651 Power Steering Pressure Switch Input fault<br />P1700 Transmission system problems<br />P1701 Reverse Engagement Error<br />P1702 Transmission system problems<br />P1703 Brake On/Off Switch out of Self-Test Range<br />P1704 Transmission system problems<br />P1705 Manual Lever Position Sensor out of Self-Test Range<br />P1709 Park or Neutral Position Switch out of Self-Test Range<br />P1710 Transmission system problems<br />P1711 Transmission Fluid Temperature Sensor out of Self-Test Range<br />P1713<br />thru<br />P172 Transmission system problems<br />P1729 4x4 Low Switch Error<br />P1740 Transmission system problems<br />P1741 Torque Converter Clutch Control Error<br />P1742 Torque Converter Clutch Solenoid Faulty<br />P1743 Torque Converter Clutch Solenoid Faulty<br />P1744 Torque Converter Clutch System Stuck in Off Position<br />P1745 Transmission system problems<br />P1746 Electronic Pressure Control Solenoid - Open circuit<br />P1747 Electronic Pressure Control Solenoid - Short circuit<br />P1749 Electronic Pressure Control Solenoid Failed Low<br />P1751 Shift Solenoid No. 1 Performance<br />P1754 Coast Clutch Solenoid circuit malfunction<br />P1756 Shift Solenoid No. 2 Performance<br />P1760 Transmission system problems<br />P1761 Shift Solenoid No. 3 Performance<br />P1762 Transmission system problems<br />P1767 Transmission system problems<br />P1780 Transmission Control Switch circuit is out of Self-Test Range<br />P1781 4x4 Low Switch is out of Self-Test Range<br />P1783 Transmission Over-Temperature Condition<br />P1784 Transmission system problems<br />P1785 Transmission system problems<br />P1786 Transmission system problems<br />P1787 Transmission system problems<br />P1788 Transmission system problems<br />P1789 Transmission system problems<br />P1900 Transmission system problems

on May 23, 2011 | Ford F Cars & Trucks

1 Answer

Code p025a fuel pump module tested relay it is good why is there power on # 85 with key off


DTC P025A: Fuel Pump Flow Control Module Enable Circuit
The engine control module (ECM) supplies voltage to the fuel pump flow control module (FPCM) when the ECM detects that the ignition is on. The voltage from the ECM to the FPCM remains active for 2 seconds, unless the engine is in crank or run. While this voltage is being received, the FPCM closes the ground switch of the fuel pump and also supplies a varying voltage to the fuel tank pump module in order to maintain the desired fuel rail pressure.
Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the FPCM.
  2. Ignition OFF, install a test lamp between the control circuit terminal 13 and ground.
  3. Ignition ON, verify that a test lamp illuminates for 2 seconds.
  4. ?‡'
    If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

  5. If all circuits test normal, replace the FPCM.
Relay for what ? Which engine do you have LY6 or non LY6

Aug 24, 2015 | 2009 Chevrolet Silverado 1500

1 Answer

I have a 2004 n16 Pulsar, Done 100k, Engine using 1 litre oil / 500 klm (1 tank fuel). blows out heaps of smoke when accelerating after throttle off down hill. Car now will not start - turns over but will...


Lots of ideas...
1 litre of oil every 500km is very heavy consumption if it has no major leaks. Oil on overrun and taking off from lights is a strong indication the valve stem seals are hard and worn out.
You can try a product called AT205 reseal and add it to your oil - It contains a plasticiser to restore the rubber, rather than a softening and swelling agent like stop smoke products. However, your engine may have bigger problems than just valve stems.

Using that much oil may have fouled the spark plugs. Pull them all out and inspect for carbon build up and general black oily coating. Cleaning them with a wire brush at that stage may restore some performance to the plugs, but they will foul again quickly.

Running for 2 secs is pretty normal practice for fuel pumps. It's part of the safety features to prevent under bonnet fires and engine flooding. If you suspect the fuel pump, do either a pressure test, or flow test.
Both will require a method of bypassing the ignition cut out of the ignition. You can normally do this by feeding direct battery or ignition power to the fuel pump fuse. Just make sure you can switch it off.
Pressure testing is normally a professional job as it requires a pressure gauge to be installed on the fuel rail, then run the pump and see what pressure is produced (should be about 4 bar, or 60psi).
The flow test is more home hobbyist mechanic level. Disconnect the low pressure fuel return line from the outflow side of the fuel pressure regulator. Place a length of fuel line on the fuel pressure regulator and direct it into a small container you can locate in the engine bay, preferably below fuel rail level.
Turn on the fuel pump (using whichever hotwire method you've chosen) and run for approx 15 secs.
The amount of fuel in the container will vary from car to car, but a 200-300ml (around 7-10 oz, or whatever method you measure by) is a good number. And the fact it can pump past the fuel pressure regulator (and thus is pressurising the fuel rail) is also a good sign.

Oct 03, 2017 | Cars & Trucks

1 Answer

97 honda accord SE not getting power to fuel pump I drove my car over to my mothers house shut it off and went out to leave and my car would not start checked all the fuses and the relays then realized...


Three things you may want to check out next in your problem diagnosis:

1. You may actually be getting power to the fuel pump through the functioning fuel pump relay and the good fuse, but the fuel pump itself may have failed - you can check by disconnecting the fuel pump electrical connector, and checking for battery voltage when the ignition key is turned to "Start".

2. The ignition switch itself may have failed, since it has been recalled on this vehicle. The recalled defect may have caused a failure of the switch to deliver power to the fuel pump at startup. Here's a list of all the recalls for the 1997 Accord:

Recall - Ignition Switch Replacement 02-031 09/24/2002
Recall 02V120000: Ignition Switch Defect NHTSA02V120000 05/01/2002
Recall 99V069000: Lower Ball Joint Replacement NHTSA99V069000 04/20/1999
Recall 98V231000: Air Conditioner Wire Harness Chafing NHTSA98V231000 09/18/1998
Campaign - Front Balancer Shaft Oil Seal Replacement 00-073 03/13/2001
Recall - A/C Wiring Harness Routing 98-072 10/13/1998

3. Testing the PGM-FI main relay is fairly involved (and not detailed in the information below). You may want to re-post your query asking for the testing & diagnosis procedure for this component alone.

Below find the 1997 Honda Accord manual entry for diagnosis & testing of the fuel pump electrical circuit.

TESTING

Fuel Pump Circuit

If you suspect a problem with the fuel pump, listen for the pump to operate by removing the fuel fill cap and checking to see if the pump can be heard running during the first two seconds after the ignition key is turned to the ON position. You should hear the fuel pump motor run.

If the fuel pump can be heard running, the fuel pump's electrical circuit is likely to be OK and the fuel pump operating pressure should be checked as outlined later in this section.

Once the engine has started, the fuel pump operation is controlled by the Powertrain Control Module (PCM) via the PGM-FI Main Relay. The fuel pump receives its electrical power from the PGM-FI Main Relay, which is triggered for two seconds when the ignition switch is initially turned to the on position.

After the initial two-second startup signal is received, the PGM-FI Main Relay is controlled by the PCM. Because the fuel pump receives its power from the PGM-FI Main Relay, a problem with the ignition switch, PCM, or electrical wiring may not allow battery voltage to reach the pump.

To check the fuel pump wiring proceed as follows:

1. Make sure the ignition switch is in the OFF position.
2. Locate and detach the fuel pump electrical connector at the fuel tank.
3. You may have to remove the floor access panel. For specific details, see the fuel pump removal procedure in this section.
4. Fuel pump access is limited on some 1996-97 models of the Accord and may require you to work under the vehicle. Perform the following steps if that is the situation:

a. Raise the vehicle and safely support it on suitable jackstands.
b. Remove the protective cover from the fuel tank fuel hoses.

5. Detach the fuel pump electrical connector.
6. Connect a suitable Voltmeter between the fuel pump positive terminal of the electrical connector and a known good chassis ground.
7. Hold the electrical connector of the PGM-FI Main Relay so the wire side of the female terminals is visible and install a jumper wire between terminal Nos. 4 and 5.
8. When the ignition switch is turned ON , battery voltage should be present at the fuel pump electrical connector.
9. If the battery voltage is present, check the fuel pump's ground.
10. If the ground is "OK", check the fuel pump.
11. If battery voltage is not present, trace the wiring harness and check the cause for an open or shorted circuit.
12. If all wiring checks out, test the fuel pressure, as outlined later in this section.

Fuel Pump Pressure

The fuel pressure should be checked at the fuel rail or at the fuel feed line for the fuel rail. The fuel pressure is checked with the engine started, thus the fuel pressure gauge must not interrupt the flow of fuel to the fuel rail and the fuel injectors.

To attach a fuel pressure gauge to the pressurized fuel loop requires the use of an adapter that is capable of safely withstanding the fuel system fuel pressure.

WARNING
Checking the fuel system fuel pressure requires the use of an in-line fuel pressure gauge with the engine running. Do not perform this check if suitable test equipment and fuel fittings are not available. The fuel system operates under pressure, if any fuel leakage is noticed while performing this check STOP immediately and do not continue until the source of the leak is resolved. Do not perform this test near sources of heat, spark, or flames. This test must be performed in a well-ventilated area.


CAUTION
The fuel injection system remains 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.

To check the fuel system pressure proceed as follows:

1. Remove the fuel filler cap and relieve the residual fuel pressure. For specific details, refer to the relieving fuel pressure coverage in this section.
2. Attach a suitable fuel pressure gauge to the fuel injection fuel loop as follows:

Models such as the 1998-00 Accord have a fuel pulsation dampener which must be removed in place of the banjo bolt for testing.

1996-97 Accord with 4-cylinder engines and 1996-00 Prelude: Remove the service/banjo bolt from the end of the fuel rail. Install the fuel pressure gauge using a suitable fitting to temporarily substitute for the banjo bolt or in place of the service bolt that will allow fuel to be supplied to the gauge and the fuel rail.

1996-97 Accord with V6 engines: Remove the banjo bolt from the fuel filter outlet and install the pressure gauge using a suitable fitting to temporarily substitute for the banjo bolt and supply fuel to the gauge and the fuel rail.

1998-00 Accord: Remove the fuel pulsation damper from the end of the fuel rail and install a suitable fuel pressure gauge in its place.

3. Remove and plug the vacuum line for the fuel pressure regulator located near the end of the fuel rail.
4. Start the engine and note the fuel pressure. With the pressure regulator vacuum hose disconnected and plugged, the fuel pressure should register as follows:

2.2L engines: 38-46 psi (260-310 kPa)

2.3L engines: 47-54 psi (320-370 kPa)

2.7L engines: 40-47 psi (270-320 kPa)

3.0L engines: 41-48 psi (280-330 kPa)

If the engine won't start, turn on the ignition switch ON, wait two seconds, then turn off the ignition switch OFF. Turn the ignition switch back ON again and read the fuel pressure.

5. If the fuel pressure is higher than specification check for a pinched or restricted fuel return hose or line.

6. If the fuel pressure is lower than the specification check for a damaged fuel pressure regulator, clogged fuel filter, fuel feed line or a leak in the fuel feed line. If the fuel pressure regulator, fuel feed lines, and fuel pump are OK, replace the fuel pump and fuel filter.

The fuel pressure regulator testing procedures are located later in this section.

Once the test is complete, perform the following:

7. Carefully remove the fuel pressure gauge and test fittings.
8. Install the removed fasteners using new sealing washers.
9. Install the fuel filler cap.
10. Start the engine and check for any fuel leaks, and repair as necessary.

Oct 16, 2011 | 1997 Honda Accord

2 Answers

What other problem other than the fuel pump could stop the fuel flow


STOPPED UP FUEL FILTER - RESTRICTED FUEL FUEL LINE.OR BROKEN FUEL LINE.

Jun 18, 2010 | 1996 Chevrolet S-10 Pickup

1 Answer

Location of fuel pump for 1992 subaru loyale wagon


REMOVAL & INSTALLATION

See Figure 1


0900c15280067055.jpg enlarge_icon.gifenlarge_tooltip.gif Fig. Fig. 1: Fuel pump assembly mounted under the vehicle-1.8L engine
  1. Release the fuel system pressure. Do not reconnect the fuel pump harness.
  2. Disconnect the negative battery cable.
  3. Raise and support the vehicle safely on jackstands.
  4. Clamp the middle portion of the hose connecting the fuel tank pipe and the pump to prevent fuel from flowing out of the tank when unfastened.
  5. Loosen the hose clamp and disconnect the hose.
  6. Remove the three pump bracket mounting bolts and remove the pump together with the pump damper.

To install:
  1. Install the fuel pump and damper, and tighten the bolts securely.
  2. Install the hose and tighten the clamp screw to 9-13 inch lbs. (1.0-1.5 Nm).
  3. Install the pump bracket in position to the vehicle body and secure it with the bolts.

Take care to position the rubber cushion properly.
  1. Connect the pump harness.
  2. Connect the negative battery cable and test the fuel pump for proper operation.
  3. Check for fuel leaks.

TESTING

  1. Turn the ignition ON and listen for the fuel pump to make a growling sound. Turn the ignition OFF .
  2. Release the fuel system pressure. Disconnect the pump harness and crank the engine for 5 seconds or more. If the engine starts, allow it to run until it stops. Turn the ignition OFF and install the fuel pump connector.
  3. Disconnect the fuel hose at the fuel pump.
  4. Connect a gauge in-line using a T-fitting.
  5. Start the engine and measure the fuel pressure. If the fuel pressure is not 36-50 psi (248-344 kPa), replace the pump.
  6. Release the fuel system pressure and remove the gauge.

May 22, 2010 | 1992 Subaru Loyale

1 Answer

Will not start when hot. starter makes no different types of noise.


hello. perhaps I can assist you.

Perform this test:

Fuel pump test:

1. Get yourself a helper.

2. remove the gas cap.

3. have one person listen in the gas tank at the gas cap opening.

4. have the other person turn the ignition switch to the ON position ONLY so as the dash lights come on. Do NOT attempt to start the engine.

5. As soon as the ignition key is turned to the ON position, The person at the gas tank should hear the fuel pump run for TWO SECONDS and then it should STOP.

6. Does it ?.


If you do NOT hear it run, in most cases the fault is the fuel pump relay or the fuel pump..


As soon as you turn ON the ignition switch to start the engine a 2 second ONLY battery voltage signal is sent from the computer to the fuel pump relay and from the relay back to the fuel pump in the fuel tank. This runs the fuel pump for ONLY 2 seconds of which pressurizes the fuel system in preparation to start the engine.

Once the engine starts, The computer BYPASSES the fuel pump relay and sends constant contionous battery voltage from the computer to the oil pressure switch of which is now CLOSED because the oil pressure is UP because the engine is running. Therefore the battery voltage flows thru the oil pressure switch back to the fuel pump to run the fuel pump constantly until you turn OFF the engine.

Oct 01, 2009 | 2003 Cadillac CTS

1 Answer

Low gas pressure in 96 sunfire. Replaced the oxygen sensor, vacuum hose, fuel pump and fuel filter. Fixed the ignition regulator. When I shut off the car it sometimes fires right up right away. It used to...


You have mentioned that you replaced the O2 sensor. The oxygen sensor is completely ignored by the engine computer while the car is starting, and doesn't come into play at all until the engine warms up completely. Are you sure you have a fuel pressure problem? If so, replacing the O2 sensor would not have any affect.

To be sure you have a fuel pressure problem, you need to measure it. This car does not have a fuel pressure test port, so you need an inline fuel pressure test gauge. To test the pressure, connect an in-line gauge and switch your ignition switch to the "run" position. (Do not start the engine.) The fuel pump should run for two seconds. During this time when the engine is not running, you should have between 41 and 47 PSI of fuel pressure. If you start the engine, the fuel pressure should drop somewhat at idle (maybe somewhere closer to 28-35 PSI). Fuel pressure is regulated according to intake manifold vacuum, so at idle, it should be fairly low, while at higher throttle settings, it should be higher.

From what I gather, your car cranks for a long time before starting. If you suspect low fuel pressure, a defective fuel pump relay could cause that condition. The relay is located in a relay/fuse box under the hood on the driver's side of the car. If the relay fails, the fuel pump can still be energized by the engine oil pressure switch. This switch closes when engine oil pressure reaches ~4PSI. If your engine is not producing 4PSI of oil pressure while cranking, or if it takes a while to reach 4PSI, that would explain your problem.

Jul 27, 2009 | 1996 Pontiac Sunfire

1 Answer

1998 Pontiac Sunfire won't accelerate


I assume that you do not have a "check engine" light?

The next thing I would do is check the pressure from the fuel pump. You can have this done at your preferred garage, or by purchasing a fuel pressure gauge from any parts store.

Vent the fuel tank vapors by loosening the fuel cap. Remove the electric fuel pump fuse and start the engine. Allow the engine to run until it runs out of fuel and stalls. After spinning the engine over for a period of 3 to 5 seconds, turn off the ignition switch and install the electric fuel pump fuse. Next, install a fuel pressure gauge in the fuel rail supply line, and secure the fuel tank cap. With the ignition key in the on position, verify that no leaks are present and start the engine. Visually verify the PSI reading on the gauge. The pressure for your vehicle should be 41-47 PSI (Pounds per Square Inch). Hope this helps and good luck!

Jan 13, 2009 | 1998 Pontiac Sunfire

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