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Help!!! No fuel to motor

12K views 12 replies 5 participants last post by  Escape 
#1 ·
I have no gas coming from fuel pump and cannot figure out what is wrong. I changed my battery 2 weeks ago then last week my jeep wouldnt start so I pulled the fuel line under the driver door and no fuel came out when I turned the key so i bought a used pump assembly from another jeep and installed it. This worked for two days but again it will not start. I bought another used pump and installed it and still no fuel comes out. I have no codes...all fuses are good, and I swapped the relay with one of my working ones. I have no idea what is wrong. I put a voltage meter to the plug to find out if there is power and i do get some voltage but im not sure what the voltages need to be at. Any help would be greatly appreciated. I am depending on my street bike now to get me to school and it has rained on me every day so far...I need my jeep running.
 
#3 ·
yes the motor will crank but not start
 
#4 ·
May have a bad relay that turns on the fuel pump. Check for voltage going to the pump. You can also pull the relay and install a cotter to jumper across the pins in the relay base that sends power to the pump. If the pump turns on you know that the relay is bad.

Or the easiest way would be to just swap another relay in it's place and see what happens.
 
#5 ·
i tried that...any other ideas?
 
#6 ·
ok i just checked the voltages at the pump plug and pins 1,2, and 3 have voltage but 4 does not. This is the problem i know because it should show at least 12V when the key is turned on for about 5-10sec. Does anyone know what this wire is for? PLease help
 
#7 ·
Did you check the ASD Relay located under the hood.

This is what happens when you turn the key.

IGNITION SWITCH (KEY-ON) MODE
This is an Open Loop mode. When the fuel system is activated by the ignition switch, the following actions occur:
² The PCM pre-positions the idle air control (IAC) motor.
² The PCM determines atmospheric air pressure from the MAP sensor input to determine basic fuel strategy.
² The PCM monitors the engine coolant temperature sensor input. The PCM modifies fuel strategy based on this
input.
² Intake manifold air temperature sensor input is monitored.
² Throttle position sensor (TPS) is monitored.
² The auto shutdown (ASD) relay is energized by the PCM for approximately three seconds.
² The fuel pump is energized through the fuel pump relay by the PCM. The fuel pump will operate for approximately
three seconds unless the engine is operating or the starter motor is engaged.
² The O2S sensor heater element is energized via the ASD relay. The O2S sensor input is not used by the PCM
to calibrate air-fuel ratio during this mode of operation.

ENGINE START-UP MODE
This is an Open Loop mode. The following actions occur when the starter motor is engaged.
The PCM receives inputs from:
² Battery voltage
² Engine coolant temperature sensor
² Crankshaft position sensor
² Intake manifold air temperature sensor
² Manifold absolute pressure (MAP) sensor
² Throttle position sensor (TPS)
² Starter motor relay
² Camshaft position sensor signal
The PCM monitors the crankshaft position sensor. If the PCM does not receive a crankshaft position sensor signal
within 3 seconds of cranking the engine, it will shut down the fuel injection system.
8E - 270 ELECTRONIC CONTROL MODULES - SERVICE INFORMATION WK
The fuel pump is activated by the PCM through the fuel pump relay.
Voltage is applied to the fuel injectors with the ASD relay via the PCM. The PCM will then control the injection
sequence and injector pulse width by turning the ground circuit to each individual injector on and off.
The PCM determines the proper ignition timing according to input received from the crankshaft position sensor.

The wires going to your fuel pump are as follows:
1. Color = BK, Gauge 18, Ground
2. Color = BK, Gauge 20, Ground
3. Color = DB/YL, Gauge 20, Fuel level sensor
4. Color = TN/RD, Gauge 16, Fuel pump relay from integrated power module from fuel pump relay controlled by the ASD relay.

There is also the pickup strainer, fuel pressure regulator and fuel filter in the tank assembly. Did you check those also?
 
#8 ·
i swapped the asd relay with the HVAC relay since they are the same and no change... The asd fuse seems fine as well. The fuel pump works when connected to the battery. I am getting votage for three seconds but it seems to be very low voltage. It is upsetting because I can rebuild motors but cannot figure out why one wire does not have voltage. It makes no sense to me...and the stealership cannot get to my vehicle for a week. What to do besides blow the dam car up?
 
#9 ·
i checked the strainer adn filter but not the regulator
 
#10 ·
how do i check the regulator?
 
#11 ·
Maybe the alarm system has gone bad,with it thinking that the jeep is being stolen? The alarm recently went out on my friends Malibu and it kept the fuel pump from getting power, leading her to replace everything under the sun to only discover it was the alarm the whole time. Good Luck.
 
#12 ·
o geez i hope its not something that far off . I wouldnt even know where to begin checking the alarm
 
#13 ·
What did the terminal connections look like in the ASD relay? Any corrosion?

Fuel pressure should be at 59psi +/-5psi

Two fuel filters are used. One is located at the bottom of the fuel pump module. The other is located inside the module.

The new used fuel pump might just have been on it's last leg?

Your sentry ignition key might be freaked out. Do you have a second key to try? The sentry ignition sensor might be freaked out.

Bad fuel?

Spark plug gap?

Here is the whole test procedure for the fuel pump relay circuit.

P0627-FUEL PUMP RELAY CIRCUIT (CONTINUED)
For the Engine circuit diagram (Refer to 9 - ENGINE - SCHEMATICS AND DIAGRAMS).
For a complete wiring diagram Refer to Section 8W.
² When Monitored:
With the ignition on. Battery voltage greater than 10.4 volts and the ASD sense switch is on.
² Set Condition:
Actual Fuel Pump Relay state is not equal to desired state. One Trip Fault. Three good trips to turn off the MIL.
Possible Causes
(A916) FUSED B+ CIRCUIT
(F942) FUSED IGNITION SWITCH OUTPUT CIRCUIT
(K31) FUEL PUMP RELAY CONTROL CIRCUIT
(K31) FUEL PUMP RELAY CONTROL CIRCUIT SHORTED TO GROUND
FUEL PUMP RELAY
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1. FUEL PUMP RELAY OPERATION
Ignition on, engine not running.
With a scan tool, actuate the Fuel Pump Relay.
Is the Fuel Pump Relay operating?
Yes >> Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No >> Go To 2
2. FUEL PUMP RELAY
Turn the ignition off.
Remove the Fuel Pump Relay from the IPM.
Measure the resistance of the Fuel Pump Relay Coil.
Is the resistance between 70 to 90 ohms?
Yes >> Go To 3
No >> Replace the Fuel Pump Relay.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
9 - 710 ENGINE ELECTRICAL DIAGNOSTICS WK
P0627-FUEL PUMP RELAY CIRCUIT (CONTINUED)
3. (A916) FUSED B+ CIRCUIT
Ignition on, engine not running.
Using a 12-volt test light connected to ground, probe the (A916) Fused B+ circuit.
Does the test light illuminate brightly?
Yes >> Go To 4
No >> Repair the open or short to ground in the (A916) Fused B+ circuit. Inspect the related fuse and repair
as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
4. (F942) FUSED IGNITION SWITCH OUTPUT CIRCUIT
Ignition on, engine not running.
Using a 12-volt test light connected to ground, probe the (F942) Fused Ignition Switch Output circuit.
Does the test light illuminate brightly?
Yes >> Go To 5
No >> Repair the open or short to ground in the (F942) Fused Ignition Switch Output circuit. Inspect the related
fuse and repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
5. (K31) CONTROL CIRCUIT OPEN
Turn the ignition off.
Disconnect the C3 PCM harness connector.
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage
the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform
diagnosis.
Measure the resistance of the (K31) Fuel Pump Relay Control circuit from the IPM to the appropriate terminal of
special tool #8815.
Is the resistance below 5.0 ohms?
Yes >> Go To 6
No >> Repair the open in the (K31) Fuel Pump Relay Control circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
6. (K31) CONTROL CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (K31) Fuel Pump Relay Control circuit in the IPM.
Is the resistance below 100 ohms?
Yes >> Repair the short to ground in the (K31) Fuel Pump Relay Control circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No >> Go To 7
WK ENGINE ELECTRICAL DIAGNOSTICS 9 - 711
P0627-FUEL PUMP RELAY CIRCUIT (CONTINUED)
7. PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal
push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and
Ground circuits.
Were there any problems found?
Yes >> Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No >> Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Here is the complete No Start test procedure.

NO START PRE-TEST
NOTE: The following list of items must be checked before continuing with any no start tests.
The battery must be fully charged and in good condition. A low charged battery may produce invalid test results. If
the battery is low, charge the battery and then attempt to start the vehicle by cranking the engine for 15 seconds,
3 consecutive times.
This will allow any DTCs to set that may have been erased due to a dead battery.
Try to communicate with PCM if not able to communicate check fuses.
Make sure the Powers and Ground to the PCM are OK.
Make sure the PCM communicates with the scan tool and that there are no DTCs stored in the PCM memory. If the
PCM reports a No Response condition, refer to section 8 Electrical Electronic Control Module Electrical Diagnostics
for the proper tests.
Read the PCM DTCs with the scan tool. If any DTCs are present, they must be repaired before continuing with any
other No Start diagnostic tests. Refer to the Table of Contents for the related P-code that is reported by the PCM.
Make sure that the Bus is functional. Attempt to communicate with the Instrument Cluster and VTSS, If you are
unable to establish communications refer to 8 Electrical Electronic Control Module Electrical Diagnostics for the
proper Diagnostic procedures.
The Sentry Key Immobilizer System must be operating properly. Check for proper communication with the scan tool
and check for DTCs that may be stored in the Sentry Key Immobilizer Module (SKREEM). Repair the DTC(s) before
continuing.
If no DTCs are found, using the scan tool, select Clear PCM (BATT Disconnect).
Crank the engine several times. Using the scan tool, read DTCs. If a DTC is present perform the DTC diagnostics
before continuing.
Were any problems found?
Yes >> Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No >> Go To 2
WK ENGINE ELECTRICAL DIAGNOSTICS 9 - 1139
*ENGINE CRANKS BUT DOES NOT START (CONTINUED)
2. OPEN FUSE
Check for any open fuses in the IPM or Junction Block that may be related to the No Start condition.
Are any of the fuses open?
Yes >> Replace the open fuse and check the related circuit(s) for a short to ground.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No >> Go To 3
3. SECONDARY INDICATORS PRESENT
Ignition on, engine not running.
With the scan tool, under DTCs & Related Functions, read the Secondary Indicators while cranking the engine.
Are there any Secondary Indicators present while cranking the engine?
Yes >> Refer to the Engine Electrical Diagnostics group and perform the tests related to the secondary indicator
that is reported by the scan tool.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No >> Go To 4
4. ENGINE MECHANICAL
Check for any of the following conditions/mechanical problems.
ENGINE VALVE TIMING - must be within specifications, check for broken timing components
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.
Are there any engine mechanical problems?
Yes >> Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No >> Go To 5
5. (A955) ASD RELAY OUTPUT CIRCUIT OPEN
Turn the ignition off.
Remove the ASD relay from the IPM.
Disconnect the C3 PCM harness connector.
Verify the ASD Relay is getting voltage on the Fused B+ circuits before continuing.
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage
the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform
diagnosis.
Measure the resistance of the ASD Relay Output circuit from the ASD Relay connector to the appropriate terminals
of special tool #8815, Ignition coil, and the fuel injectors.
Is the resistance below 5.0 ohms?
Yes >> Go To 6
No >> Repair the open in the (F42) ASD Relay Output circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
9 - 1140 ENGINE ELECTRICAL DIAGNOSTICS WK
*ENGINE CRANKS BUT DOES NOT START (CONTINUED)
6. FUEL PUMP DELIVERY
Verify that the Fuel tank is not empty before continuing.
Follow the diagnostics for Checking Fuel Delivery in the Driveability section of this manual.
Was the No Start condition solved after following the above diagnostic test?
Yes >> Test Complete.
No >> Check for contamination/water in the fuel. Make sure the fuel being used in this vehicle meets manufactures
Fuel Requirement, refer to the service manual.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
 
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