Moisture in fuse box causes fuel pump fuse malfunction
I have been told that moisture gets inside the fuse box causing the fuel pump fuse to malfunction and this is the reason that my car will not start on humid days or on rainy days. To me that all sounds strange. He also told me that the fuses must specifically be Volvo fuses and the right voltage of course. Secondly, the distributor cap had a bad gasket which was also causing moisture with the contacts, and is thus preventing sparks. Is there a way to seal up the fuse box to prevent future moisture from getting inside it?
Experienced mechanics share their insights in answering this question :
For this, Silicone spray is one tool I personally like to use especially on rubber or silicone seals. The spray will leave a water-tight film on the electrical component and offers a moisture resistant coating. If you would like to have this checked, an expert, like one from YourMechanic can come to your car’s location to inspect the electrical system in order to scope the problem out and pinpoint any problems.
How to Identify and Fix Common car Problems ?
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1. Engine stalls. One of the first symptoms of an issue with the fuel pump relay is an engine that suddenly stalls. If the fuel pump relay has an issue while the vehicle is operating it will cut off power to the fuel pump, which will cause the engine to stall.
The ignition circuit, which includes the ignition switch, controls power to many components, including the fuel pump and relay.
Without this relay, the engine would not receive fuel while starting. The pump that delivers fuel to the engine while the engine is running requires electricity in order to operate. This electricity is created by an oil pressure device in the engine.
Overloaded circuits, short circuits and ground faults are all legitimate reasons why your fuses blow on a regular basis or causes for your fuse box to trip out. Other causes could be a result or ageing or faulty wiring as well as power surges.
Electrical issues: Electrical faults are also significant contributors to fuel pump failures. The most common electrical issues are rusted connectors, loose connectors, or melted wiring and connectors.
Basically, the gas is coming out of the gas pump at a pressure that is too fast for the car to take in. If the air vapors do not get out fast enough and the tube gets covered by gasoline, a vacuum forms inside the nozzle which will automatically switch off the flow of gas into your tank.
If fuel pressure is even a couple pounds less than the specifications, it can cause problems. A weak pump that isn`t delivering adequate pressure can cause an engine to run lean, misfire and hesitate when accelerating. The volume of fuel is just as important as pressure.
The fuel pressure is monitored by the engine control unit via a pressure sensor and regulated via a flow control valve installed in the pump. This fuel pressure regulator is attached directly to the high-pressure pump. It measures out the supply to the high-pressure pump and thus regulates its performance.
So it has a very specific purpose, and needs a constant input pressure to work correctly. How does it affect a car when the fuel pump fuse is blown? With no fuel pump pumping the fuel the engine will die.
If a wrong fuse was installed in the fuse panel, it could cause considerable harm. If the panel fuse blows, call an experienced electrician immediately. For your own safety, don`t go near the fuse box. Getting rid of the fuse panel or swapping it for a modern circuit breaker is the wisest thing to do.
When checking a car fuse, you must make sure the blown fuse is not connected to any other component in the car. This could lead to a dangerous electrical malfunction. The blown fuse could cause the radio to not work, or it could cause the climate control system to not work properly.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
Moisture in fuse box causes fuel pump fuse malfunction
ANSWER : For this, Silicone spray is one tool I personally like to use especially on rubber or silicone seals. The spray will leave a water-tight film on the electrical component and offers a moisture resistant coating. If you would like to have this checked, an expert, like one from YourMechanic can come to your car’s location to inspect the electrical system in order to scope the problem out and pinpoint any problems.
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.
Engine crank, no coil spark, fuel pump does not kick in.
ANSWER : Hi there. There could be multiple issues causing your lack of spark problem, ranging from a minor electrical short in the main relay to an issue with your ECU. In order to know for sure, you should have a professional mobile mechanic complete an electrical problems inspection.
Not getting power to the fuel pump and the secondary air injection pump fuse keeps blowing
ANSWER : There are quite a few reports of PCM (Powertrain Control Module, AKA computer) failures causing your problem, but before you go replacing the PCM, do some more pinpoint tests. This may require you to find a wiring diagram of all the wires coming from the PCM.
The first thing I would do is to connect a scanner to the car and see if you can communicate with the PCM. As a technician, I have access to communities of technicians where repeat failures are reported. In these reports, it is most common when the PCM fails in this fashion, that you will not have PCM communication. If you do have communication and the Check Engine Light turns on with the key on, I would be leaning away from the PCM being the problem.
However, this is by no means conclusive. You could be correct in your thoughts about a wiring problem mid vehicle. On most GM vehicles, there is a connector along the frame rail for the wiring harness that services the fuel module in the tank. This has problems with corrosion because it sits under the vehicle exposed to the elements. But why am I doubtful of this, and this will require you to confirm where the power starts and stops, is you stated you didn’t have power from the fuse box. This would be before this connector and the fuel pump. If this is the case, I wouldn’t be thinking of a wiring problem mid vehicle anymore.
I am wondering if you confirmed the fuse box was getting power? It is a very common problem that when we move wiring we inadvertently move the damaged wiring and fix the problem for the short term. You may have done this when replacing the fuse box. Not to mention you seem to have an intermittent failure on your hands. This compounds the process quite a bit.
I’m not sure how you are confirming you have power at the various points, but I highly recommend a test light over a multi-meter. A test light draws current and a multi-meter does not. There can be voltage present but not a good enough connection to carry current. This is a very important distinction when you are battling bad connections. The problem with a test light though, is knowing when it shouldn’t be used. Some test lights draw too much current and can damage computer modules. Even us technicians perform tests on modules at our own risk.
The best way to test a relay is to simply use a jumper wire to bypass them. If I suspect there is a problem with the power supply to the fuel pump, this is the first thing I do. This way I can be sure it isn’t the relay or the PCM that turns the relay on. If the fuel pump does not run, use the before mentioned test light to find where the power stops. This requires you to methodically track the wire back to the fuel pump. I usually start at the central connector, if it has one. Not all of them do. I go directly to the pump if I can, but this is often not easy to access without dropping the fuel tank down. If you successfully confirm power to the pump, it maybe a bad ground, in which case the easiest way to confirm this is to add a ground yourself.
If this circuit checks out good, a few other things to check are power and ground to the PCM. Locate the wire from the PCM that powers the fuel pump relay. This can be done at the relay connector while you are testing the fuel pump circuit without the relay. When you turn the key on, on of the four terminals should receive power from the PCM for a few seconds. It will turn off after a couple of seconds if the PCM doesn’t see a signal that the motor is running. This is normal operation.
As for the air pump, I wouldn’t think this is an indication of the problem unless this occurred at the exact same time as the fuel pump failure. If so, I would suspect a wiring harness is shorting to ground somewhere. If they didn’t occur at the same time, this is most likely a separate issue.
The challenge you have here is isolating each part of the system. The PCM, the fuel pump relay, or a wiring issue. The PCM is actually fairly easy to check. Is the Check Engine Light on with key on and does it communicate with a scanner? Then follow the fuel pump relay test I outlined above. If it is a bad connection somewhere in the system, you will need a good wiring diagram and a well thought out plan to isolate where the problem is. This can be the most difficult to diagnose, especially if the problem is intermittent. Find a wiring diagram and study it carefully. If you’d like help, you can have a qualified technician, such as one from YourMechanic, to inspect your car’s loss of power and make the correct repairs.
Good luck. I hope I have been of assistance.
Replaced fuel pump. Car won’t start. 2002 Infinity I35
ANSWER : Hi there – the metal component you describe is a fuel check valve on the fuel return line. Its function is to maintain a small amount of pressure in the fuel system so that starting does not require the fuel pump to run very long before the engine will start. Having replaced the fuel pump and fuel filter, I would check fuel pressure while the car is running. This is to check the fuel pump relay for burned contacts that won’t support full electrical current to the pump, and for proper fuel pressure – a malfunctioning fuel pressure regulator could also restrict power and higher speeds if pressure is too low. I would recommend an inspection of the fuel system 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.
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.
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.
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.
