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Discussion Starter · #1 ·
Hey, so its been a minute since I had VIDA connected in my car. I figured it would be time for a checkup to see if anything new would surprise me, and of course, there was. Car is a 06 T5 M66 with 193k. I get the code ECM-2900 Fuel Pressure faulty signal. Fuel pressure sensor was recently replaced with a bosch unit and from readouts in VIDA, appear to be working correctly(?). I logged fuel pressure and fuel pump duty cycle, and this is what I got.



At the right, there is a drop in duty cycle and rise in pressure. This was during a full throttle pull to ~4500 rpm. It seems pressure is reading normally and increases when it should (to the pressure it should be tho?). Whats interesting is that while pressure rises and stays risen, duty cycle plummets? You can see there are other quick instances where duty cycle freaks out as well.

So, does this appear to be a bad PCM or a failing fuel pump? My duty cycle at warm idle is around 50%.
 

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You need a new pump. 50% at idle is too high.

You need to look at demanded vs delivered fuel pressure. This graph is kinda meaningless without knowing load.
 

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Discussion Starter · #3 · (Edited)
You need a new pump. 50% at idle is too high.

You need to look at demanded vs delivered fuel pressure. This graph is kinda meaningless without knowing load.
I'm by no means any VIDA wiz, so I apologize for that. Ever since I got the car and have had VIDA, duty cycle has been around that area. The code is relatively new. I'm not saying that the pump isn't the answer, i just want to be sure. From what I seen while glancing over while logging, demanded vs actual fuel pressure stay pretty close to within one another. The code also comes back almost immediately after being cleared, which also confuses me as I would think a pump issue would take time to register during different throttle conditions, etc, but it could just be triggered by the high duty cycle at idle too.

Also, the pump passes the VIDA fuel pressure test and gets all the way up to around 660kpa without issue.
 

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Are these graphs WOT pulls or something? I would add more parameters to give a fuller picture of what is being shown. Ideally something that relates to load like MAF kg/h and or RPM. Also be aware you will not hit max load unless you get to 3rd gear and even then you want to be going up hill. 1 and 2 do not max out load.

There is also a fuel pump quick test in VIDA... If you do that what comes up? 3 possible options: PEM bad, new FPS bad, pump bad. The idle duty cycle of the pump should be in the 30-40% range IIRC, VIDA has the actual range in the more info part. 85% is also (allegedly) maximum dutycycle for the pump. I have never seen mine go above 85%.
 

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85% output from ECM is offset to 100% duty cycle by PEM. The slope changes.
 

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Discussion Starter · #6 ·
Are these graphs WOT pulls or something? I would add more parameters to give a fuller picture of what is being shown. Ideally something that relates to load like MAF kg/h and or RPM. Also be aware you will not hit max load unless you get to 3rd gear and even then you want to be going up hill. 1 and 2 do not max out load.

There is also a fuel pump quick test in VIDA... If you do that what comes up? 3 possible options: PEM bad, new FPS bad, pump bad. The idle duty cycle of the pump should be in the 30-40% range IIRC, VIDA has the actual range in the more info part. 85% is also (allegedly) maximum duty cycle for the pump. I have never seen mine go above 85%.
If I hook up again, I will map MAF kg/h,it just always seems the graphs get a little hectic with more then a couple things mapping, but that's also to someone who again, isnt any sort of VIDA wiz. I most likely edited the post to include the VIDA fuel pump results as you already had the thread opened, but yes, the car passes the quick test in VIDA for the fuel pump. It follows the exact example curve given and doesn't have any immediate signs of being bad. I took out the PEM and opened it up to check out the circuit board, and it appeared it was one of the ones that was never mounted outside, as it was perfectly clean and corrosion free.

With the above results, I would assume the PEM is fine and the FPS is also fine as its readings don't appear "faulty" at all. I might try to pop in my old fuel pressure sensor if I can find it, but with the higher duty cycle at idle, I would probably guess that's the reason for the code.
 

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Discussion Starter · #7 ·
Sooo, the code just... went away? I filled my tank completely full one night, and since that point on, my CEL turned itself off and has stayed off. That's kinda puzzuling, so if anyone has any reason they think that might happen, I'd love to hear it. The more interesting part of the whole CEL turning itself off though is that I am catless with no spacers or anything, but the CEL hasnt even came back on from that either, even with the 150-200 miles I have put on it since.
 
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