Fuel pressure

Fuel pressure

we did a rebuild kit on the fuel pump a week or so ago and a few days later while driving down the street i suddenly got no rev when i pushed the gas peddle like no gas and then it stalled and will not start.
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wondering if its something else completely or something that was done wrong on the fuel pump?

My car has 240000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :

Hi There,
It sounds like the fuel pump rebuild was a success if the van was running for a bit. You may want to test the voltage to the fuel pump to be sure it is operating consistently. If there is consistent voltage, this should indicate that the fuel pump relay is good. Next try checking the fuel pressure to be sure the fuel pressure is consistent. If it is not you may want to check the fuel pressure regulator. The fuel pressure regulator is a device which controls the pressure of fuel supplied to the fuel injectors on an engine. This works by bleeding off a portion of the fuel flow to the injectors from the fuel pump to control the fuel pressure. Fuel is pumped from the fuel tank to the fuel rail by the fuel pump. The fuel pressure regulator is normally mounted after the fuel rail to ensure that the fuel rail has priority in fuel flow. The valve in the regulator controls the amount of fuel that is bled from the fuel rail by opening an outlet port to allow fuel to flow back into the fuel tank. All injectors need a pressure difference between the inlet and the outlet of the injector to spray fuel into the combustion chamber. This is called the base pressure. If this is not happening correctly, you will experience intermittent fluctuations in starting and maintaining the engine running as you have described. I would suggest having a professional from YourMechanic come to your location to diagnose and inspect your vehicle.

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NOTE: Fuel pressure specification is 400 KPa +/- 34 KPa (58 psi +/- 5 psi). Turn the ignition off.

If your testing the fuel pressure from the pump you can do that on the fuel rail on the engine. There will be a cap that screws off with a needle valve under it. You should get about 50 psi.

Fuel pressure for most vehicles should stay in a 5- to 10-psi range. But, techs should make sure to look at the service information for the specifications. Other data PIDs used to regulate the fuel pump include the engine position sensors.

Best Answer. The fuel pressure spec for this vehicle is 58 psi (+/- 5 psi).

Start the car and let it idle. Install a fuel pressure gauge, run the pump, and note the pressure reading. Then compare it to the manufacturer specification. If the pressure is low, you should address that problem.

Low fuel pressure can lead to engine misfires, low acceleration, rough idles, and engine stalls. If your check engine light is on and your car has been stalling out, you may have a fuel pump failure.

When an engine is idling, it may be pulling 20 inHg of vacuum, which translates to roughly 10psi. The reference to the regulator will allow it to adjust and lower the pressure in the rail to 48psi, resulting in 58psi effective pressure, which is the same as the base pressure.

A: Pressure requirements vary, so we recommend checking the correct fuel pressure for your specific vehicle in the manual. But, as a reference, normal fuel pump pressure is generally between 45 and 58 psi (or 3.2 to 3.4 bar).

The 2023 Chrysler Grand Caravan features a nine-speed automatic transmission with rotary e-shift, providing an impressive highway fuel economy rating of 8.4 litres per 100 kilometres (34 miles per gallon).

Listed EPA fuel economy for the 2006 Dodge Grand Caravan SXT is 18mpg in the city and 25mpg on the highway.

The fuel pressure on these engines should be 56 to 62 psi with the key on and engine off.

High fuel pressure will make an engine run rich, while low fuel pressure will make an engine run lean or not at all. Fuel pressure readings that are higher than manufacturers specifications are generally caused by a problem in the return line fuel components.

Low fuel pressure means you have a lean condition and too much air is mixing with the amount of fuel in the combustion chamber, causing them to run hot. This can melt the spark plugs. If you notice you are replacing the spark plugs too often, test the fuel pressure.

Typical working pressure on a common rail system is about 1600 to 1800 bar, or 23,000 to 26,000 psi.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

How long and what is the process to replace a fuel pressure sensor?

ANSWER : A professional mechanic would require roughly 5 hours. (If just the regulator is replaced that takes about 1 hour). Some parts, as noted below, cannot be re-used, you need a precision inch pound torque wrench, FSM instructions (and TSB updates if applicable; procedure was changed in 2007 for instance) and the system has to be bled when done.

Below is partial list of steps, copied and pasted directly from the service manual:

1. Disconnect battery and put protective material in front of the charge air cooler (CAC) or damage to the CAC may occur.

2. Remove air cleaner assembly.

3. Disconnect the oil drain tube from the crankcase vent oil separator.

4. Loosen the air cleaner outlet tube clamp and detach the air cleaner outlet tube from the turbocharger.

5. Remove the bolts, the crankcase vent oil separator and the air cleaner outlet pipe as an assembly.

6. Remove and discard the crankcase vent oil separator press-in-place gasket. (To re-install, tighten to 13 Nm (115 lb-in).

7. Disconnect the PCM electrical connector (BE SURE BATTERY IS DISCONNECTED FIRST!) and retainer. Disconnect the in-line electrical connector and position the engine wiring harness on the engine.

8. Remove the pushnuts and the glow plug module heat shield.

9. Disconnect the high-pressure fuel injection pump electrical connector and detach the retainer from the glow plug module bracket. Disconnect the glow plug module and the exhaust gas recirculation temperature (EGRT) sensor electrical connectors, detach the wiring retainer and position the wiring harnesses aside.

10. Remove the nut and position the ground strap aside. To install, tighten to 13 Nm (115 lb-in).

11. Remove the engine wiring harness bolt. To install, tighten to 13 Nm (115 lb-in).

12. Remove the heater supply tube nut. To install, tighten to 13 Nm (115 lb-in).

13. Remove the bolts and the glow plug module bracket. To install, tighten to 13 Nm (115 lb-in).

14. Remove the nut and position the transmission fluid indicator tube aside. To install, tighten to 8 Nm (71 lb-in).

Warning: Do NOT disconnect the glow plug electrical connector before dislodging the seal from the valve cover or the wiring harness may be damaged.

15. Using an appropriate tool, dislodge the glow plug wiring harness seals from the valve cover.

16. Disconnect the glow plug electrical connectors by pulling on the glow plug wiring harness tee above the seal. Remove the glow plug wiring harness.

17. Remove the nut and position the crankcase ventilation drain tube aside.

18. Disconnect the wiring harness retainer from the valve cover stud.

19. Disconnect the wiring harness retainer from the generator bracket.

20. Disconnect the A/C pressure switch electrical connector. Position the harness aside.

Warning: Do not bend or flex the heater supply tube or damage to the tube may occur.

21. Remove the stud bolts, bolts and the valve cover. Remove and discard the valve cover gasket. To install, tighten to 9 Nm (80 lb-in).

Warning: Contact with exposed fuel injector wiring, if energized, may result in electric shock.

Use care when working on or around energized fuel injector wiring. Fuel injector wiring supplies HIGH VOLTAGE to operate the fuel injectors of course, you disconnected the battery though.

22. Disconnect the fuel rail pressure (FRP) sensor electrical connector.

Warning: Fuel injection equipment is manufactured to VERY precise tolerances and fine clearances (think space shuttle). To prevent fuel system damage, it is essential that absolute cleanliness is observed when working with these components. Always install fuel system caps on any open orifices or tubes.

23. Remove the FRP sensor. To install, tighten the FRP sensor in 2 stages.

Stage 1: Tighten to 7 Nm (62 lb-in).
Stage 2: Tighten an additional 40 degrees.

24. Bleed the high-pressure fuel system.

If you feel like this job may be too overwhelming or run into any issues, consider YourMechanic to get it done. One of our mobile technicians can come to your home and replace the fuel pressure sensor at your own convenience.

Read Full Q/A … : Fuel pressure

Installed new delphi fuel pump and fram fuel filter. still no pressure on fuel rail valve and wont start. 2003 Chevrolet Tahoe

ANSWER : Hi there – I suspect you have weak power getting to the fuel pump. I would first check the voltage coming out of the fuel pump relay. If the contacts in the relay are burned, you will not get reliable current flow to the pump. Check the fuel pump ground as well (voltage drop across the ground, not just continuity). I recommend a fuel system inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.

Read Full Q/A … : Fuel pressure

I have a 1981 e-350 with dual fuel tanks the p.o. added a third tank and 3 electric fuel pumps along with sepparate gauges and swi

ANSWER : The switch you are referring to is vended with the required electrical and fuel schematic (I just looked in the box) that answers your installation question. If you want an advance view, here is a link as well. Yes, you need a return line and just refer to the aforementioned link. If you are retrofitting back to OEM, I strongly encourage you to buy the original Factory Service Manual (FSM). There are lots of details attending this system and obviously it is difficult to recount it all here. The FSM will make your life much easier and you can then make sure your installation is perfect. Alternatively, YourMechanic can dispatch a certified mechanic and perform the whole retrofit and check out if you desire. Just request and schedule a generic service such as fuel pump service and the mechanic will come to your location and estimate the parts and labor required. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

Read Full Q/A … : Fuel pressure

Fuel pressure

ANSWER : Hello,
You may want to try checking the fuel pump relay. The relay wires should have ground on two wires, power on one wire and switched power on another wire. To activate the fuel pump your ECU actually connects one of the ground wires to complete the circuit and send power to the fuel pump. If the wires all have power running through them, then it is likely you have a faulty relay. The wire coming from the fuel pump is the other ground wire. I would recommend having an expert from YourMechanic come to your location to diagnose your wiring as this can be very difficult and time consuming without the proper wiring diagram.

Read Full Q/A … : Fuel pressure

Turn ignition on fuel pressure goes to 60 lbs two seconds and fuel pump relay clicks pressure drops 5 lbs then slowly drops to 0to

ANSWER : It sounds like this fault may have more going on than just the fuel delivery issue. The vehicles ECU will command the fuel pump to turn on normally when a vehicle is started. If the car only primes for the second when the key is turned, then for some reason the ECU may be pulling the fuel.

This can happen due to a failure with various sensors or ignition component, such as the oil sender, ignition switch, ECT sensor, or various other failed sensors. If the car has codes stored in the ECU it may lead to more information as to what is going on. A qualified technician will be able to diagnose this fault no start fault and perform any repairs required.

Read Full Q/A … : Fuel pressure

I have a truck that won’t run and is not getting gas to the engine. Fuel pump is running, have a new filter and new fuel pressure

ANSWER : Hi There,
It sounds like you may have a clogged fuel injector or potentially a faulty injector that is fried internally. I would suggest testing them if you have access to a multi meter. Disconnect the injector from the electrical connector and set your multi meter to Ohms mode and measure the resistance of the injector. After testing all injectors, compare the resistance. They should be the same or very close. If they are not, they will likely need to be replaced.

Read Full Q/A … : Fuel pressure

Just replaced my fuel pump but its not getting any power tested fuel pump relay and fuel fuse both good tested the wires all good.

ANSWER : You need to look at the theft light on dash to make sure it comes on and goes off when you turn the key to the on position. If light comes on and stays on then your theft system is causing the fuel pump to not be engaged. I recommend you check the theft system and then scan the computer for theft system codes. You may need to reprogram the keys to work or you have an bad sensor for the ignition key in the steering column.

Read Full Q/A … : Fuel pressure

Replaced fuel pressure regulator and fuel pump,still no power going to fuel pump

ANSWER : This sounds like you may not have any power going to the fuel pump relay. The relay wires should have ground on two wires, power on one wire and switched power on another wire. To activate the fuel pump your ECU actually connects one of the ground wires to complete the circuit and send power to the fuel pump. If the wires all have power running through them, then it is likely you have a faulty relay. The wire coming from the fuel pump is the other ground wire. I would recommend having an expert from YourMechanic come to your location to diagnose your wiring as this can be very difficult and time consuming without the proper wiring diagram.

Read Full Q/A … : Fuel pressure