DIY 535 LPFP Discussion/Tester Thread
- Thread starter PFS
- Start date
If determined to be necessary, would either have to add one in, or deal with possible longer crank start scenarios. Neither of those are big deals to do, if either of them are even a problem. I may throw one in my N54 just to see what's what with starting and no check valve. Should have a couple samples to play with show up in the next week or two.
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@PFS and @Martymill
Cool. Curious which check valve? Does crack pressure matter 1psi vs 5psi? After installing my LPFP I'm in long crank land and fuel pressure dropping like a rock on shutdown. This makes me think the new pump doesn't have a check valve or the o-ring in my HPFP could have failed or both. ~50K miles.
Also considering opening up my stock bucket and installing a new pump like the 285 ? demon ? pump which has a CV ?
Cool. Curious which check valve? Does crack pressure matter 1psi vs 5psi? After installing my LPFP I'm in long crank land and fuel pressure dropping like a rock on shutdown. This makes me think the new pump doesn't have a check valve or the o-ring in my HPFP could have failed or both. ~50K miles.
Also considering opening up my stock bucket and installing a new pump like the 285 ? demon ? pump which has a CV ?
That's a pretty open ended question. Low pressure does drop like a rock after shutdown, that's normal. The check valve intent isn't to keep pressure up, it's to stop the whole system from emptying. Remember, any restriction you add reduces your pump output, so if we pick a badass pump with huge flow potential but then hamstring it with a restrictive check valve, we're no better off than we were using some cheaper low-flow pumps with built in check valves.
There is middle ground, but first thing is first, for a single 295 system is it even a concern? Worth testing, as there are benefits to cost, flow, and complexity if it's not needed.
Chris
Unfortunately, my system empties immediately after shutdown. Low pressure PSI goes from 70's -> 0 immediately. Prior to the pump, it would hold 15 to 30 psi overnight and light immediately after button press. When hot I have to prime/pressurize the system with the fuel pump at least 3 or 4 times to briefly (half second) get pressure up to 15 -17psi for it to light. Even when cracking the fuel rail to replace injectors or the PCV valve I was expecting some pressure and got nothing. I have a thread about it over in technical with a log of the behavior. Doublespaces thinks it could be the HPFP. All of this to say, if I can eliminate this nuisance with a check valve between the LPFP and the HPFP, I'm game. Sorry to de-rail. Back to the 295 discussions.
Sounds like you have a separate issue. I didn't see it posted -what stage 2 lpfp and what pump are you using?
I don't know the spool setup. But at you're describing is a hardware issue, I'd recommend creating a thread in the troubleshooting subforum. May be able to help, I have gone through a very similar issue with different pumps. Turns out it was a combination of things.
Could be, but that's neither here nor there at the moment (we can dig deeper into that later). I agree with doublespaces above, you should make a ts thread, I don't think the pump itself is the cause of your issues.
Testing is on hold; wife got in an accident at work and damn near chopped her toe off, so I'm being run ragged doing what she normally makes look easy.
Not yet. I apologize, I want to do this testing but the wife is disabled and taking up nearly all the spare time -the in-laws came to help for a while (and I'm lucky... my in-laws are awesome!) but it's still dominating my life. The good news is she is improving and I am hoping to get back to something kinda like normal in the beginning of Feb. I've been brainstorming on the 5 series pump though and have some ideas on how to juice this sucker up, and/or get you guys to a respectable fueling capability level without breaking the bank. More to come soon guys, I appreciate your understanding and patience.
Chris
Does anyone else have any more info on the 535 pump. Wanting to run a single 535 instead of a 450 but I want to keep my ekpm3. Or can point me to a link of some testing results
I just ran across the other thread where you said you put a check valve in. Did you do any write up for that? I have a spare stock fuel pump that I want to throw a 535 pump in the stock bucket. Only question I have is really regarding the check valve. I had planned to buy the upgraded fuel lines from PR and not sure how I can make a check valve work.
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