ECUx logs of my S4 testing my fuel pump theory...
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AudiWorld Super User
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ECUx logs of my S4 testing my fuel pump theory...
I have been trying to chase down a lean spike for those that don't know. I decided it seems to happen at peak boost and as the boost tapers off, the car richens up.
The link at the bottom of the page shows a fuel pump test. It clearly shows that a walbro 255hp (like I run) opens a valve and dumps fuel pressure at 85psi. I run a 4bar FPR, which is 58psi. That means at arond 27psi of boost (85psi fuel pressure), my fuel pump should crap out. Sure enough, my lean spike seems to happen when I spike to 27psi. As my boost tapers, the fuel comes back and the car richens up.
This is 1.8bar or 27psi. Right at 85psi fuel pressure.
<a href="http://s195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/?action=view¤t=KalebWB18bar.jpg" target="_blank"><img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/KalebWB18bar.jpg" border="0" alt="Photobucket"></a>
This is 1.6 bar or 24psi. 82 psi fuel pressure, or just under the 85psi limit.
<a href="http://s195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/?action=view¤t=KalebWB16bar.jpg" target="_blank"><img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/KalebWB16bar.jpg" border="0" alt="Photobucket"></a>
At 1.5bar or 22psi. 80psi fuel pressure, or 5 psi under the limit.
<a href="http://s195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/?action=view¤t=KalebWB15bar.jpg" target="_blank"><img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/KalebWB15bar.jpg" border="0" alt="Photobucket"></a>
Here the ECUx logs laid over each other. Blue line has a 27psi boost spike right where the car goes lean. The rest are at under 85psi fuel pressure. No lean spike.
<center>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image007.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image009.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image010.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image011.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image012.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image013.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image014.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image020.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image021.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image022.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image023.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image033.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image032.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image031.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image030.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image029.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image028.png" alt="Photobucket - Video and Image Hosting"><br><br>
</center>
<center>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image027.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image026.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image025.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image024.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image034.png" alt="Photobucket - Video and Image Hosting"><br><br>
</center>
The load on all of these runs is past 191, so I don't think this is a software problem. It seems clear to me that the Walbro 255hp does indeed crap out at 85psi. At this point, the only thing left to do is try a different pump. There is apparently a Bosch 044 HP that can handle the fuel pressure I need.
The link at the bottom of the page shows a fuel pump test. It clearly shows that a walbro 255hp (like I run) opens a valve and dumps fuel pressure at 85psi. I run a 4bar FPR, which is 58psi. That means at arond 27psi of boost (85psi fuel pressure), my fuel pump should crap out. Sure enough, my lean spike seems to happen when I spike to 27psi. As my boost tapers, the fuel comes back and the car richens up.
This is 1.8bar or 27psi. Right at 85psi fuel pressure.
<a href="http://s195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/?action=view¤t=KalebWB18bar.jpg" target="_blank"><img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/KalebWB18bar.jpg" border="0" alt="Photobucket"></a>
This is 1.6 bar or 24psi. 82 psi fuel pressure, or just under the 85psi limit.
<a href="http://s195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/?action=view¤t=KalebWB16bar.jpg" target="_blank"><img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/KalebWB16bar.jpg" border="0" alt="Photobucket"></a>
At 1.5bar or 22psi. 80psi fuel pressure, or 5 psi under the limit.
<a href="http://s195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/?action=view¤t=KalebWB15bar.jpg" target="_blank"><img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/KalebWB15bar.jpg" border="0" alt="Photobucket"></a>
Here the ECUx logs laid over each other. Blue line has a 27psi boost spike right where the car goes lean. The rest are at under 85psi fuel pressure. No lean spike.
<center>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image007.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image009.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image010.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image011.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image012.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image013.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image014.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image020.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image021.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image022.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image023.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image033.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image032.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image031.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image030.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image029.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image028.png" alt="Photobucket - Video and Image Hosting"><br><br>
</center>
<center>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image027.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image026.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image025.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image024.png" alt="Photobucket - Video and Image Hosting"><br><br>
<img src="http://i195.photobucket.com/albums/z209/system_s4000/MRC%20Fuel%20Pump%20Test/image034.png" alt="Photobucket - Video and Image Hosting"><br><br>
</center>
The load on all of these runs is past 191, so I don't think this is a software problem. It seems clear to me that the Walbro 255hp does indeed crap out at 85psi. At this point, the only thing left to do is try a different pump. There is apparently a Bosch 044 HP that can handle the fuel pressure I need.