Fuel Pressure Regulator Post-Mortem exam

[VetteMed]

Pulled the plenum this morning, and removed the original fuel pressure regulator. I hacked up the black top of it to remove it, and inspect the diaphragm. There was lots of rust particles in the inside of the regulator, and the diaphragm has multiple wrinkles in it, a few of which appeared to have progressed to tiny pinholes.

Here's some pics:

http://i680.photobucket.com/albums/vv163/agchoset/IMG_3130.jpg

http://i680.photobucket.com/albums/vv163/agchoset/IMG_3134.jpg

http://i680.photobucket.com/albums/vv163/agchoset/IMG_3136.jpg

Got a replacement on the way from RockAuto, hoping to have that by Saturday.

Wonder what's next....

[A26B]

Man, that's nasty looking! Looks like there must have been some water in ther for quite awhile. I've cut a couple apart and never seen anything like that. Pity it can't be disassembled, rebuilt & reassembled.

[VetteMed]

Jerry, yeah I was thinking the same thing, must have had water in there at some point. Of course, with almost 200k miles, anything's possible over the years. My old injectors also had some surface scale on the upper flange around the strainer basket.

The regulator's aluminum base is such a nice piece, it's a shame it can't be salvaged. Luckily I got a new aftermarket replacement for around $70.

[TFENT]

Correct me if I am wrong, but I believe I read on here somewhere that an adjustable regulator was available for the LT-5. This is the only part I did not replace under the plenum when I had mine apart. I didnt want to use an off brand OE replacement.

Anyone clarify this?

[VetteMed]

Correct me if I am wrong, but I believe I read on here somewhere that an adjustable regulator was available for the LT-5. This is the only part I did not replace under the plenum when I had mine apart. I didnt want to use an off brand OE replacement.

Anyone clarify this?

Apparently LPE used to sell an adjustable. Not any more, unfortunately. I thought about going with an ACDelco, but this whole project is bleeding me quite dry, and anything has to be better than the crusty piece that it's replacing.

Besides, lots of Delco parts are made by the lowest bidder anyway, so I don't feel that it's likely to be much different.

[GOLDCYLON]

That is correct I tried to buy one of those a while back used but the owner and I could not agree on a price for the LPE unit. I was told later that that was really only needed for a boosted Car. Andrew great Pics BTW

[XfireZ51]

That is correct I tried to buy one of those a while back used but the owner and I could not agree on a price for the LPE unit. I was told later that that was really only needed for a boosted Car. Andrew great Pics BTW

Yes. Really no need to change FP. Plenty of injector for NA purposes.

[HAWAIIZR-1]

http://i78.photobucket.com/albums/j86/hawaiizr1/DSC02614.jpg

http://i78.photobucket.com/albums/j86/hawaiizr1/DSC02613.jpg

As mentioned, maybe no real gain to an LPE adjustable FP regulator unless for certain applications, but here is what it looks like.

[TFENT]

http://i78.photobucket.com/albums/j86/hawaiizr1/DSC02614.jpg

http://i78.photobucket.com/albums/j86/hawaiizr1/DSC02613.jpg

As mentioned, maybe no real gain to an LPE adjustable FP regulator unless for certain applications, but here is what it looks like.

That's auto porn! I WANT one!!

[XfireZ51]

Where's the adjustment or is it a VAFPR? Does it have different spring rates available?

[VetteMed]

Probably a set screw in the center of the black "hat".

[VetteMed]

Got the new regulator today from RockAuto - it's a KEM part, and it's clearly the identical casting to stock, even has the same letters stamped into it in the same places. Here's some pics:

http://i680.photobucket.com/albums/vv163/agchoset/IMG_3147.jpg

http://i680.photobucket.com/albums/vv163/agchoset/IMG_3146.jpg

http://i680.photobucket.com/albums/vv163/agchoset/IMG_3145.jpg

[TFENT]

Let us know how it performs and what the pressure readings look like under use. I am curious to know...

[XfireZ51]

Looks pretty dead nuts! How much? Good to know of another source.

[VetteMed]

Looks pretty dead nuts! How much? Good to know of another source.

Around $70 from RockAuto, it was marked down as a wholesaler closeout. They also have an Airtex/Wells unit, more expensive, I'd guess it's probably the same casting too after seeing this one.

[HAWAIIZR-1]

Where's the adjustment or is it a VAFPR? Does it have different spring rates available?

Like Vettemed stated, adjustment screw in the center of the hat. Not sure about the different spring rates or range of adjustment. Just bought it off Ebay last year or so. I called LPE back then but the guy did not know much about it. I'm sure Graham Behan would know all about it; maybe developed it?

[VetteMed]

Installed the new FPR today, with some of Jerry's viton o-rings. Interestingly, the 2 metal fuel pipes that run from the junction block where the rubber lines run into, seem to be a permanent press-fit. There were 2 o-rings that I didn't use, so I am wondering if that was a change made to the design at some point? Can anyone confirm or deny?

Everything went together perfectly otherwise, and my crappy Fuel pressure gauge read 48-49psi with key-on, engine off. No leaks! :)

http://i680.photobucket.com/albums/vv163/agchoset/IMG_3148.jpg

http://i680.photobucket.com/albums/vv163/agchoset/IMG_3150.jpg

[A26B]

Installed the new FPR today, with some of Jerry's viton o-rings. Interestingly, the 2 metal fuel pipes that run from the junction block where the rubber lines run into, seem to be a permanent press-fit. There were 2 o-rings that I didn't use, so I am wondering if that was a change made to the design at some point? Can anyone confirm or deny?

Everything went together perfectly otherwise, and my crappy Fuel pressure gauge read 48-49psi with key-on, engine off. No leaks! :)



Sounds like all went very well for you.

There are permenant pipe connections that do not come apart for seals. The reason there are 9 seals in the pkg is because the same o-rings are also used at the fuel feed & return block (2 seals), bringing the total to 9.

I also sell the fuel feed & return block seals (pkg of 2) separate, for replacement with random plenum pulls.

[VetteMed]

Got the plenum back on this morning, fuel pressure reading around 43psi at idle, with vacuum hose connected. Jumps to about 51-52psi with vacuum hose removed at idle.