Just like the title says, I'm chasing fuel pressure issues and looking for comparison (yes, I've replaced the FPS). Can anyone use VIDA or an OBD code reader to check fuel pressure at warm idle, 60 MPH cruise and full boost? TIA...
Data Request: T5 Fuel Pressure Readings
2 reading
drjonez
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Just like the title says, I'm chasing fuel pressure issues and looking for comparison (yes, I've replaced the FPS). Can anyone use VIDA or an OBD code reader to check fuel pressure at warm idle, 60 MPH cruise and full boost? TIA...
Here are the datalogs from when I was tuning my car:
https://drive.google.com/drive/folders/0Bwa750uR_cqZdWJYSlhlLVVFYkU
Fuel pressure is in columns Z and AA.
All the logs have a 3rd gear WOT pull, but there should be some data captured at cruising speeds as well.
https://drive.google.com/drive/folders/0Bwa750uR_cqZdWJYSlhlLVVFYkU
Fuel pressure is in columns Z and AA.
All the logs have a 3rd gear WOT pull, but there should be some data captured at cruising speeds as well.
Goodness is that awesome. Thank you, sir!
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I'll get mine up tomorrow, too much to do today since my FX-8350 got here ha but it's usually smooth between 43psi and 47psi while cruising, and i'll put up the full boost psi tomorrow when I take the kid to school.
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Hi
are those from stock or stage2? as the file names would indicate, that is already tuned, isnt it?
Based on actual/requested boost, it is most certainly a tuned file.
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ah ok, no point then to compare my data with yours as it will definitely look like something is wrong :}
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Correct me if I'm wrong, but isn't the purpose of the fuel pressure regulator to smooth out all of those rougher transitions between requested pressures and actual pressures? It looks like yours has a metric buttload of spikes above and below, in some cases extremely so like on the left it spikes up halfway to the next step on each step, and then on the way down almost never reaches the requested pressures.
In my opinion, the uniformity of each side with each of it's three steps being not close to the requested pressures with that extreme of variations from requested would be the source of your code. Notice going up after the huge spikes it is relatively on the line, but going down it doesn't even hit it. I know it's not going to follow the requested perfectly, but when it's not even touching it...kinda raises some eyebrows there in my opinion. It even levels off at the requested time but it is like 20kPa above where it should be each step down.
In my opinion, the uniformity of each side with each of it's three steps being not close to the requested pressures with that extreme of variations from requested would be the source of your code. Notice going up after the huge spikes it is relatively on the line, but going down it doesn't even hit it. I know it's not going to follow the requested perfectly, but when it's not even touching it...kinda raises some eyebrows there in my opinion. It even levels off at the requested time but it is like 20kPa above where it should be each step down.
VIDA talks about the very issue you're mentioning....and states it is perfectly normal. I'll grab a screenshot at some point....
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Our cars use a fuel pressure sensor, not regulator. The difference is the sensor merely tells the ECM what fuel rail pressure is, there is no mechanical intervention/dampening.
I normally associate ECM-2900 with a fuel pump issue. The key in diagnosing this is knowing what the fuel pump duty cycle specification is. Off the top of my head, I do not know it. Since you have VIDA, you should be able to find it there.
If you put a mechanical fuel pressure gauge at the fuel rail Schrader valve connection, have your car connected to VIDA, start the car and watch the ECM fuel pressure sensor reading compared to the fuel pressure gauge reading. Also monitor the fuel pump duty cycle.
You will confirm a weak pump with a duty cycle too high while maintaining the specified fuel pressure (400 kPa).
It wouldn't hurt to check residual fuel pressure. Shut the engine off and watch your fuel pressure gauge. It should hold pressure for several minutes after shutdown. If pressure drops quickly right after engine shutdown, replace the pump. This issue however, is normally associated with a long cranking condition to start the engine.
I normally associate ECM-2900 with a fuel pump issue. The key in diagnosing this is knowing what the fuel pump duty cycle specification is. Off the top of my head, I do not know it. Since you have VIDA, you should be able to find it there.
If you put a mechanical fuel pressure gauge at the fuel rail Schrader valve connection, have your car connected to VIDA, start the car and watch the ECM fuel pressure sensor reading compared to the fuel pressure gauge reading. Also monitor the fuel pump duty cycle.
You will confirm a weak pump with a duty cycle too high while maintaining the specified fuel pressure (400 kPa).
It wouldn't hurt to check residual fuel pressure. Shut the engine off and watch your fuel pressure gauge. It should hold pressure for several minutes after shutdown. If pressure drops quickly right after engine shutdown, replace the pump. This issue however, is normally associated with a long cranking condition to start the engine.
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