fuel pressure
fuel pressure
Hey everyone. Having trouble with 98 gle. Getting p300 and p0301. Checked about every emission control sensor and replaced plugs, wires, knock sensor and right bank O2 upstream sensor. Read someone else had a bad injector and fixed it and solved the misfire issue so I did a fuel pressure test for starters and have to turn ignition on several times to get to 43 psi and the pressure rapidly drops to nothing. At idle am getting 39 psi. Punched the return line closed while idling and pressure shot way up. Did not let it go over 60. I am suspecting the fuel pressure regulator. Was wondering what others opinion was and if there is any other checks I could do before getting a new one.
Re: fuel pressure
Welcome.
It sounds like the regulator is doing what its supposed to.
The fuel pressure drops while its running, or after its shut off?
It might drop slowly after shut down.
If it drops real fast, it might be leaking from the injector, its o-rings, or back into the fuel pump. Some times the o-rings get cut when folks remove and install an injector.
If you have 39 psi at idle, I think your problems are elsewhere.
Does the code set under certain circumstances?
How does the car drive in general?
P0300 can be a tough code, good luck.
It sounds like the regulator is doing what its supposed to.
The fuel pressure drops while its running, or after its shut off?
It might drop slowly after shut down.
If it drops real fast, it might be leaking from the injector, its o-rings, or back into the fuel pump. Some times the o-rings get cut when folks remove and install an injector.
If you have 39 psi at idle, I think your problems are elsewhere.
Does the code set under certain circumstances?
How does the car drive in general?
P0300 can be a tough code, good luck.
-
NutriaforBreakfast
- Posts: 1316
- Joined: Wed Sep 26, 2007 1:41 pm
- Car: Nissan Maxima 1995 VQDE engine
Re: fuel pressure
Replaced wires? The car doesn't use plug wires but it does use coil
packs. I would pull the #1 cylinder coil pack and check the resistance
of the coil. Also (with safety glasses) start the engine with the coil
pack OFF the car and a GOOD spark plug in the coil pack. Use a coat
hanger wire (grounded off of the car body!) and create a spark between the plug and the coat hanger wire and see if it is a strong spark. This is evidence the
coil and plug are good.
For a misfire you can't limit your thinking to just one system. When you
looked at emissions, did you remove the EGR tube from the back of the
plenum? That area has been a bad place for carbon to restrict air flow
and create EGR related issues.
Are you smelling a lot of gasoline while the engine is running? This might
be a sign of injector leaking.
I have gotten the knock sensor code reading while having a misfire code. That doesn't mean the knock sensor is bad but it is probably picking up the fact the engine is misfiring and moving around.
you will get through this
packs. I would pull the #1 cylinder coil pack and check the resistance
of the coil. Also (with safety glasses) start the engine with the coil
pack OFF the car and a GOOD spark plug in the coil pack. Use a coat
hanger wire (grounded off of the car body!) and create a spark between the plug and the coat hanger wire and see if it is a strong spark. This is evidence the
coil and plug are good.
For a misfire you can't limit your thinking to just one system. When you
looked at emissions, did you remove the EGR tube from the back of the
plenum? That area has been a bad place for carbon to restrict air flow
and create EGR related issues.
Are you smelling a lot of gasoline while the engine is running? This might
be a sign of injector leaking.
I have gotten the knock sensor code reading while having a misfire code. That doesn't mean the knock sensor is bad but it is probably picking up the fact the engine is misfiring and moving around.
you will get through this