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Anonymous Posted on Jun 03, 2010
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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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Karl Kittsteiner

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  • Posted on Jun 03, 2010
Karl Kittsteiner
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The pump should be running and producing fuel when ignition switch is in the on position.

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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 .
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Feb 19, 2017 • 2000 Ford Taurus
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Ford OBD-II Trouble Codes
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on May 23, 2011 • Ford F Cars & Trucks
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1answer

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.

  4. If all circuits test normal, replace the FPCM.
Relay for what ? Which engine do you have LY6 or non LY6
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Aug 24, 2015 • 2009 Chevrolet Silverado 1500
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1answer

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.
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Oct 03, 2017 • Cars & Trucks
1helpful
1answer

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.
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Oct 16, 2011 • 1997 Honda Accord
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2answers

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.
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Jun 18, 2010 • 1996 Chevrolet S-10 Pickup
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1answer

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.
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May 22, 2010 • 1992 Subaru Loyale
2helpful
1answer

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.
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Oct 01, 2009 • 2003 Cadillac CTS
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1answer

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.
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Jul 27, 2009 • 1996 Pontiac Sunfire
0helpful
1answer

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!
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Jan 13, 2009 • 1998 Pontiac Sunfire
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