LS fuel pressure regulation issue

[K5Rob]

Hey guys I have been battling high fuel pressure using the corvette style filter/regulator on my 5.3 swap which has a returnless truck intake. Fuel pump is from a late 90s Vortec 350 which fit my
TBI sending unit perfectly, p/n P240KC, which cross references with EP381. I am chalking this up to a faulty filter/regulator.
I have tried two so far (off brand and Wix) and getting anywhere from 70-100 psi at the rail. Ready to ditch these completely and try an adjustable regulator with an inline filter. Was going to run it in the following order:

1. In-tank pump (with 100 micron sock)
2. 40 micron filter between tank and FPR
3. Return style adj. FPR set to 58 PSI
4A. Return line from FPR to tank
4B. Supply line from FPR to fuel rail

Does this setup sound correct and is this a viable solution? I want this to take place of the corvette style filter/regulator as to not have to completely redo all my plumbing. My understanding is if the corvette style reg isnt a dud out of the box then it will fail in short order

 

[Camar068]

I have the same setup with a EP381. I'd like to see references of such failures. I'm on my second and my pressures have always been steady. Only changed first due to Lean codes on both banks.

[edit] my apologies, ep381 being the fuel pump. I've used 2 of the Wix 33737's with no issues. Steady 58-60psi.

My apologies again for my confusion.

 

[K5Rob]

I have the same setup with a EP381. I'd like to see references of such failures. I'm on my second and my pressures have always been steady. Only changed first due to Lean codes on both banks.

Same as in vette regulator? What brand are you using?

 

[K5Rob]

I have the same setup with a EP381. I'd like to see references of such failures. I'm on my second and my pressures have always been steady. Only changed first due to Lean codes on both banks.

Here is a link to one of many

WIX filter/regulator - CorvetteForum - Chevrolet Corvette Forum Discussion

C5 Tech - WIX filter/regulator - I see these are once again available? Seems to me they weren?t for awhile. Are they good? I ask because I suckered for a Walbro pump Wix C5 filter kit on eBay a couple years ago for the LS1 in my son?s S10. Neither were legit parts. No name crap. Pump failed in...

www.corvetteforum.com

Most others you will find on any site under the reviews, such as amazon, summit etc

 

[Camar068]

@K5Rob running the topic/issue through my mind, what took 2 cycles to vroom when I did the swap, I now have to stop after 4, then 2 cycle vroom....if you follow me. I'll dig into mine and post if it's not solid.

But this is a different issue than you're posting. I don't have an issue with what's going on, don't want to hack ur thread with another issue. Probably bad check valve for my issue.

[edit] tested my pressure, solid 58 running but bled down to 54 after a minute. Again my issue different than yours.

Glad I read yours though, future reference.

 

[K5Rob]

[edit] tested my pressure, solid 58 running but bled down to 54 after a minute. Again my issue different than yours.

Yes they are said to bleed down as you describe. And thank you for not hijacking. My issue is they are not regulating anywhere near 58. More like 70, 90, 100. Right out of the box. May i ask what brand you are running?

 

[Scottgenex]

Yes they are said to bleed down as you describe. And thank you for not hijacking. My issue is they are not regulating anywhere near 58. More like 70, 90, 100. Right out of the box. May i ask what brand you are running?

I'll throw my hat in. I've been running a Microgaurd on my swap for four years. It was a third of the cost of the WIX and I was just going to run it to get the project going and upgrade later. Never happened. Runs around 58ish, last I checked was a month or so ago. Reading the reviews, most out of the box failures seem to be from three years ago and on. Wonder if the manufacturing changed since then.

I've tended to steer clear of WIX when it came to fuel filters. A ways back they had an issue on the DMAX stuff. Left a bad taste in my mouth cause of it. Oil filters all day long though.

 

[K5Rob]

I'll throw my hat in. I've been running a Microgaurd on my swap for four years. It was a third of the cost of the WIX and I was just going to run it to get the project going and upgrade later. Never happened. Runs around 58ish, last I checked was a month or so ago. Reading the reviews, most out of the box failures seem to be from three years ago and on. Wonder if the manufacturing changed since then.

I've tended to steer clear of WIX when it came to fuel filters. A ways back they had an issue on the DMAX stuff. Left a bad taste in my mouth cause of it. Oil filters all day long though.

Great to know. Thats what I was worried of - bad manufacturing as of the last few years. I agree that most these failures seem to be recent. The problem is who makes one that works, and when you need to replace it, which you will, where do you get one?
Most of the people who have had failures end up getting a wix and claim that wix solves the problem. That is not true in my experience. I also read people that found wix filters in delco boxes. One mentions wix changed their manufacturing facility. Obviously a fuel filter needs to be changed every so often. My main question is anyone running an adjustable regulator and how is that working for them

 

[K5Rob]

I'll throw my hat in. I've been running a Microgaurd on my swap for four years. It was a third of the cost of the WIX and I was just going to run it to get the project going and upgrade later. Never happened. Runs around 58ish, last I checked was a month or so ago. Reading the reviews, most out of the box failures seem to be from three years ago and on. Wonder if the manufacturing changed since then.

I've tended to steer clear of WIX when it came to fuel filters. A ways back they had an issue on the DMAX stuff. Left a bad taste in my mouth cause of it. Oil filters all day long though.

By the way, i searched oreillys for that microgard filter as i know orilleys sells the microgard name. It is part number 33737. Same part number as wix.

 

[Scottgenex]

By the way, i searched oreillys for that microgard filter as i know orilleys sells the microgard name. It is part number 33737. Same part number as wix.

Interesting. Guess I got lucky with mine if by chance it's made in the same facility. Originally I was going the adjustable FPR route until I figured the Corvette filter thing out. Hopefully someone chimes in with how theirs has held up.

 

[Camar068]

Yes they are said to bleed down as you describe. And thank you for not hijacking. My issue is they are not regulating anywhere near 58. More like 70, 90, 100. Right out of the box. May i ask what brand you are running?

for the regulator wix 33737 (RA) was the first I got when I installed the engine 8 yrs ago. Link below what I ordered to troubleshoot my issue. Weird it doesn't say part #.

https://www.amazon.com/dp/B000C9UJUU?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_2#averageCustomerReviewsAnchor

 

[K5Rob]

for the regulator wix 33737 (RA) was the first I got when I installed the engine 8 yrs ago. Link below what I ordered to troubleshoot my issue. Weird it doesn't say part #.

https://www.amazon.com/dp/B000C9UJUU?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_2#averageCustomerReviewsAnchor

Thanks for the reply. The trouble with Amazon is they are notorious for knockoff auto parts. You may be buying a Wix but get a cheap knockoff disguised as a Wix. They sort of disguise the seller since everything is bought through the Amazon platform it can be difficult to distinguish if the actual seller is reputable or not. Frustrating. I do agree something happened in the past few years and now they are all duds. From what I am reading in the reviews I am not even sure if you even eventually find one that works or not. I admit i am often a sucker for messing around with cheaper parts as long as its not something like internal motor parts. But for the price of messing around I could have gone the adjustable regulator route and been done. I just dont know if my logic is correct is why I was asking if someone could confirm my setup plan outlined in post #1

 

[TotalyHucked]

I have nothing to offer on the aftermarket manual regulator, but if I ever have a real issue with my setup, that's the route I'll go.

I will throw my .02 in the ring, I have only run either Wix or AC Delco filters and only had an issue with 1 faulty Wix. It didn't give me too much pressure though, it didn't give enough. Other than that one filter, I've had zero issues from my setup for 60k miles now. That said...I went through 4 EP381 pumps that all died on me. 2 Delco, 2 Delphi equivalent. I finally went to a genuine (there's lots of knockoffs) Walboro 255 and it's been fine since. Due to the extreme fuel pressure, I'd lean toward it being your pump instead of the regulator.

 

[Ricko1966]

That setup should work just fine.

 

[Hunter79764]

Agree, the proposed setup should work great. Alternatively, depending on your ECM setup and your tuner's input, doing a vacuum referenced rail is (I would argue) the best arrangement. "Returnless" was implemented as a cost savings.
But before you do too much, make sure that your return line is clear, and your tank is appropriately vented. The venting is more likely to cause low pressure, but a blocked/pinched/obstructed return line can certainly raise pressure.