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iauto8, ASE Certified Technician
Category: Car
Satisfied Customers: 137
Experience:  15 year ASE Auto Technician. European import specialist.
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Volvo S60: my Volvo doesnt want to run on idle or start up,

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my Volvo doesn't want to run on idle or start up, i have to start it a couple of times to get it going and when i come to a stop it could run for a while and then just die on me
The most common cause of this is a failing throttle body. The less common cause would be fuel pump or fuel pressure sensor. I will post test procedures for both. Chris...

1. Check the electrical connection at the throttle body. Ensure it is fully engaged and visually inspect the pins.

2. Check the condition of the throttle plate. Removal will be necessary. If throttle plate is badly carbon contaminated or oil soaked, check the PCV system.

3. While the Electronic Throttle Actuator (ETA) is removed, check the motor winding resistance by measuring between terminals 1 and 4. Specification is 1.2-3.5 ohms.

4. Check resistance between terminals 2 and 3. Specification is 1000-1500 ohms. Check resistance between terminals 2 and 6. Resistance will be about 820 ohms at closed throttle and sweep to 1580 ohms at Wide Open Throttle (WOT). Check resistance between terminals 2 and 5. Resistance will be about 1480 ohms at closed throttle and will sweep to 500 ohms at WOT.

5. If the ETA fails any of these tests, replace it.

6. If the ETA is passing all tests, clean the bore and blade with a solvent soaked rag. Reinstall and clear code.

1. Normal fuel pressures are as follows:
For first 5 seconds of engine startup - 55 PSI.
Idle - 43-45 PSI.
Low load - 55 PSI.
High load - 60 PSI.
It is normal for fuel pressure to vary with engine load.
Fuel pressure should hold after the key is cycled off.

2. The Pump Electronic Module (PEM) controls current flow to the fuel pump to regulate pressure. The Engine Control Module (ECM) pulses a reference voltage from the PEM to ground with a varying duty cycle. A higher duty cycle will produce more pressure. Normal duty cycle at 43-45 PSI (idle) is 35% (+/- 5%) and will range from 20-80% depending on load. PEM current to the fuel pump will vary from about 2 amps at idle to 8 amps at max request.

3. Fuel pressure signal voltage at startup (55 PSI) is about 2.4. Idle is 1.8-2.1v (43-45 PSI).

4. If direct power/ground is applied to the fuel pump, it should create 90 PSI. Fuel pump current draw will be 8-10 amps during this.

5. There are many bulletins out on this system. One is for relocating the Pump Electronic Module (PEM) if replaced due to factory locations being prone to corrosion. If there are blown fuses, there is a bulletin to add an extra power feed for the ejector pump. Some 2003-3004 vehicles had a recall for the fuel pressure sensor. See TNN 23-181 for fuel pressure sensor recall information.
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