6.7 Cummins fuel pressure sensor P0191 P0193
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- Опубліковано 17 гру 2023
- This information should be good for all 6.7 Cummins experiencing a P0191 or P0193. When talking about the pigtail from Max Tow, I misspoke and it’s actually for an aftermarket fuel pressure gauge, not an aftermarket sensor.
Great info man. Been trying to diag this code myself without blind throwing money at my truck. You're the first guy to mention the idle test cycle the truck does.
I also have the fluctuating pressure with engine off. I thought for sure that was a sign of a bad connector, or wiring, but maybe not.
Thank you. The dealer I went to wasn’t even familiar with the test cycle. The service manager ended up asking me for the link to the sub harness I used.
One of these days I’m going to make a shorter vide showing specs of everything and exactly how to test the sensor.
@@WestRocConversions-es3pu please do make a video showing specs of everything and how to test the sensor. this code have me puzzled, as I have had this code for approximately two weeks now. I already changed the fuel filter, but apparently that didn't work. thanks for the video!
Great video, I’m having the same exact problem with my 2012. Did you end up using another OEM fuel rail sensor? Or did you purchase an aftermarket one?
Having same
Issue as
You
Plus the dreaded lightning bolt. Every start is rough during idle.
Then it behaves after warming up. 2018 6.7 HO
Does it have to throw that code for that to be the issue?
I’m not very familiar will all the different codes pertaining to the high pressure fuel sensor, but I believe there are high and low voltage codes as well that this test could help with. The high/low voltage codes could be tricky though. The sensor ultimately reads pressure and relays the info to the ecu via voltage. I your getting high/low voltage, it could be a lack of, or too much fuel pressure at the fuel rail.
That could be caused by a failing FCA (fuel control actuator) which regulates the flow of fuel into the cp3 pump. The FCA typically causes a surging/rough idle or hard start. The surging is not to be confused with the ECU running it’s test mentioned in the video. The surging will be very noticeable.
The high/low voltage could also be caused by a failing fuel pressure relief valve. That’s caused by the internal spring becoming weak and not holding rail pressure, or the valve is sticking holding too much pressure. The relief valve can be tested by looking at your commanded and actual fuel pressure. They should be within a few hundred psi of each other. Typically you’ll have too much bleed off at high rpm or under a big load and the truck will feel sluggish/down on power. At wide open throttle or heavy load situations, the commanded fuel pressure should be around 26,000psi.
Then there’s the cp3 itself, or the injectors. The injectors can fail in a few ways. They can bleed pressure into the cylinders which would cause blueish/white smoke on startup, poor fuel economy, excessive black smoke, and elevated EGT’s. They can also bleed too much fuel back to the tank. There’s a specific procedure to test for injector return rate.
Great video, I’m having the same exact problem with my 2012. Did you end up using another OEM fuel rail sensor? Or did you purchase an aftermarket one?
Great video, I’m having the same exact problem with my 2012. Did you end up using another OEM fuel rail sensor? Or did you purchase an aftermarket one?
Yeah, I bought a second Bosch sensor and it was perfect. Been going strong ever since.
Thank you so much for your help!