Bushwa
Member
I'm putting some effort into diagnosing the P0087 Fuel Rail/System Pressure - too low issue, and thought it would be good to log some of my findings and diagnostics here for future benefit.
I've read some past threads where $1000's of dollars are spent with symptoms still persisting.
Symptoms:
Hot start, cranks a little longer than usual. Cranks fast, but takes longer to fire.
When cold, sometimes the rev's drop when coming to a stop, stumbles, and catches before stalling.
Runs good most of the time.
Sometimes on hot start after sitting for 30 to 60 minutes:
Restricted Performance warning, codes thrown are P0087 Fuel Rail/System Pressure - too low, and P0106 Manifold Absolute pressure/barometric sensor range/performance
Sometimes warning goes away and power is normal. Sometimes it remains and you gotta drive real slow.
I've ran a tank of fuel system cleaner and another with a different fuel injector cleaner\lubricant. No luck there.
I've replaced the MAP sensor, no change.
I've been running some data logs to see what's going on. Logging every drive so I can get some data to compare between running fine, and under the restricted performance warning.
So far, I've been able to see that the low pressure pump sensor output is fairly constant and within normal values of "voltage" between 2 and 3.1V.
The HP pump fuel rail pressure is consistently between 500 and 580 PSIG at idle or closed throttle.
The HP pump fuel rail pressure peaks and maintains 1900 to 2000 PSIG when under moderate or heavy load.
I'll post some charts of the data once I get a couple clean comparable samples, I didn't log the same parameters each run previously, so it's not a good set to compare.
Some observations:
1. when under restricted performance, there are a few instances of light load or throttle opening where the fuel rail pressure doesn't increase immediately it stay around the idle value.
2. when operating normally, the fuel pressure jumps consistently where there is a throttle opening.
3. fuel rail pressure always drops almost instantly when load is removed or the throttle is closed.
I'm thinking it's a sensor issue, sensor gets hot/warm from hot engine after parked for 30-60 minutes, and doesn't read correctly, load is applied, pressure doesn't rise, it throws code and sets restricted performance.
However, i don't have values for what the fuel rail pressure should be at idle and under load. Is 500 to 600 normal for idle/no load and 1900 to 2000 normal for under load?
MAYBE it's due for HPFP too? It does have 320,000 km. Don't know if they've ever been changed.
I understand with the correct diag tool, dealer or shop can put a manual gauge on the fuel pressure rail and run one or the other HP pump to test their actual performance. I have an appointment in 9 days, but I'm hoping to fix myself before then
I've read some past threads where $1000's of dollars are spent with symptoms still persisting.
Symptoms:
Hot start, cranks a little longer than usual. Cranks fast, but takes longer to fire.
When cold, sometimes the rev's drop when coming to a stop, stumbles, and catches before stalling.
Runs good most of the time.
Sometimes on hot start after sitting for 30 to 60 minutes:
Restricted Performance warning, codes thrown are P0087 Fuel Rail/System Pressure - too low, and P0106 Manifold Absolute pressure/barometric sensor range/performance
Sometimes warning goes away and power is normal. Sometimes it remains and you gotta drive real slow.
I've ran a tank of fuel system cleaner and another with a different fuel injector cleaner\lubricant. No luck there.
I've replaced the MAP sensor, no change.
I've been running some data logs to see what's going on. Logging every drive so I can get some data to compare between running fine, and under the restricted performance warning.
So far, I've been able to see that the low pressure pump sensor output is fairly constant and within normal values of "voltage" between 2 and 3.1V.
The HP pump fuel rail pressure is consistently between 500 and 580 PSIG at idle or closed throttle.
The HP pump fuel rail pressure peaks and maintains 1900 to 2000 PSIG when under moderate or heavy load.
I'll post some charts of the data once I get a couple clean comparable samples, I didn't log the same parameters each run previously, so it's not a good set to compare.
Some observations:
1. when under restricted performance, there are a few instances of light load or throttle opening where the fuel rail pressure doesn't increase immediately it stay around the idle value.
2. when operating normally, the fuel pressure jumps consistently where there is a throttle opening.
3. fuel rail pressure always drops almost instantly when load is removed or the throttle is closed.
I'm thinking it's a sensor issue, sensor gets hot/warm from hot engine after parked for 30-60 minutes, and doesn't read correctly, load is applied, pressure doesn't rise, it throws code and sets restricted performance.
However, i don't have values for what the fuel rail pressure should be at idle and under load. Is 500 to 600 normal for idle/no load and 1900 to 2000 normal for under load?
MAYBE it's due for HPFP too? It does have 320,000 km. Don't know if they've ever been changed.
I understand with the correct diag tool, dealer or shop can put a manual gauge on the fuel pressure rail and run one or the other HP pump to test their actual performance. I have an appointment in 9 days, but I'm hoping to fix myself before then