shawkur16v Posted February 17, 2022 Report Share Posted February 17, 2022 Recently finished up my link installation, and everything went great. However, the fuel pressure sensor I installed 0-150 PSI from lodoller motorsport seems to be inaccurate. With the engine off, if I turn the fuel pump on it will show ~130PSI, with the engine idling it will show ~117 psi. This is a return style system, and I installed the sensor in the feed line. The setup is as goes: Low pressure in-tank feed pump->Large particle filter->High pressure AEM 400LPH Inline->-6 feed up to engine bay->-6 fitting with 1/8NPT for pressure sensor->Ethanol content sensor->Small particle filter->Fuel rail->-6 return to tank. I would expect with the engine off and pump running to see around 58PSI with the 4 bar FPR. When I turn the pump off it will read and hold at ~50PSI for a few minutes at least. I'm not planning to use the fuel pressure in closed loop, so it's not a big deal that it appears to be incorrect but I would prefer that it were reading correctly. Quote Link to comment Share on other sites More sharing options...
Adamw Posted February 17, 2022 Report Share Posted February 17, 2022 Can you give us a log and a copy of the tune so we can see voltage and calibration setup etc. Quote Link to comment Share on other sites More sharing options...
Brad Burnett Posted February 17, 2022 Report Share Posted February 17, 2022 Im curious if moving the sensor to the fuel rail will show a different value. Unless your ethanol content sensor has a high volume bypass adapter, I would put it on the return side installed in a manor that fuel will rest in it even in the event of low flow. The content sensors have a small internal diameter and can be flow restrictive. Quote Link to comment Share on other sites More sharing options...
shawkur16v Posted February 24, 2022 Author Report Share Posted February 24, 2022 Apologies for the delay, had to take the transmission out of the car. Here are 2 log files, 1 of the fuel pump prime after key on, and another idling Scirocco16vT_Base_V2.pclx FeulPumpPrime.llgx FuelPumpRunning.llgx Quote Link to comment Share on other sites More sharing options...
Adamw Posted February 24, 2022 Report Share Posted February 24, 2022 I get the impression the sensor is telling the truth and you do actually have a fuel pressure control problem. Either the regulator is not working or it is plumbed wrong or there is too much flow for it to regulate. You can see in the log with the engine off the battery voltage jumps up 0.5V when the pump finishes priming so it is obviously working very hard. You will need to verify with a mechanical gauge or another known good sensor, but my feeling is the reported fuel pressure is probably accurate. Quote Link to comment Share on other sites More sharing options...
Confused Posted February 24, 2022 Report Share Posted February 24, 2022 I wasn't sure a few weeks ago whether my fuel pressure sensor was reading right, as it disagreed with my mechanical gauge on the regulator. "A man with one watch always knows what time it is. A man with two watches is never sure." So, I popped the sensor out, and T'd it into the feed to my ECU and boost gauge, then used a small regulator and my compressor and looked at all 4 together - the compressor's regulator gauge, the mechanical boost gauge, the ECU's MAP reading and the fuel pressure reading as reported via PC Link. This confirmed that the fuel sensor was reading correctly, and my fuel pressure gauge on the regulator was wrong. Swapped the fuel pressure gauge on the regulator for a new GoFastBits one, and it reads exactly the same as my fuel pressure sensor. Quote Link to comment Share on other sites More sharing options...
shawkur16v Posted February 24, 2022 Author Report Share Posted February 24, 2022 I believe the regulator is at least working to some extent. If I remove the vacuum source from the regulator with the vacuum hose capped off my AFR goes crazy rich, presumably from the higher pressure. I'll remove the sensor and put a mechanical gauge in that spot and check what it shows. I'll also replace the second fuel filter while I'm down there. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.