Important(!) New(?) Discovery(?) about fuel pressure/ Feed The Beast Mods

[Clipper]

Howdy, All...

I posted this in another thread, but I thought it was important, and might get "lost in the shuffle"....so...

Stuttering on acceleration for a long time, slowly getting worse...finally put in a fuel pressure gauge.

Meantime, I had dropped and cleaned the fuel tank, replaced the lift pump, cleaned out the fuel manager.
I actually replaced the lift pump with a Shurflo 5000-series 1.5GPM triple diaphragm pump,
regulated to 10 psi with a polypropylene external pressure relief valve.
Still had 10 PSI at idle, dropped to 0 on light acceleration, heavy vacuum on heavy acceleration.

Finally decided to do the Feed The Beast mods, and I discovered something IMPORTANT. I drilled out the filter/manager housing, installed the new barb, flushed, etc. and tried blowing through it...I STILL had a LOT of back pressure!!!

The little cylindrical fuel strainer in the middle of the fuel filter housing was BADLY clogged. I have seen it mentioned in other threads, as in "make sure it's still there; it can sometimes be removed accidentally when you remove the fuel filter element." But I read everything I could find on the FTB mods, including on the old site, and nobody seems to have made the point that this little screen needs to be pulled and cleaned.

Now granted, I have 433k miles on my truck, and mine was probably clogged a little more than average, but...it didn't happen overnight. I can't help but wonder what would have happened to my fuel pressure if I had cleaned it BEFORE I did the FTB mods...and I can't help but wonder how many other guys' fuel pressure problems might be caused by this little screen being clogged?

Getting it out was a bit difficult. I pulled and pulled, and it moved a little, but it seemed to be stuck. Then I noticed that it as it moved, it was scraping up more black stuff from the hub...I scraped the hub clean, and the strainer came off pretty easily.

I scraped the screen clean with a small flat screwdriver...the black stuff clogging it was hard, like dried gummy sludge. Gotta dig pretty hard, but be careful you don't poke through the screen...I backed the screen with my finger, and was very careful. Used lots of spray Gumout. After I cleaned it, I decided to replace it anyway...it is definitely NOT a dealer item, it is a Stanadyne part, part no. 29244. $2.43 plus shipping.
http://www.btlrus.com/99717B.pdf (page 11)

Incidentally, my fuel pressure is now a steady 10 at idle, and drops to about a steady 7 under all but the heaviest acceleration. I am measuring pressure right at the IP inlet.

On heavy acceleration, it drops towards zero, but...lots of black smoke. The Heath boost regulator is my next mod.

Forewarned is forearmed...!!

--Clipper

 

[NVW]

I saw your other post, good info:thumbsup:

 

[3500GMC]

Good catch. Thanks for the part number.

The 6.5 crowd rocks! :thumbsup:

 

[buddy]

I had to convince one online vendor that the part even existed, shortly thereafter it showed up on his site and stressing importance to make sure its still there

 

[JiFaire]

I had to convince one online vendor that the part even existed, shortly thereafter it showed up on his site and stressing importance to make sure its still there

ROFL... yeah, more than one of us has had that conversation ... mine was with a dealer, because the local NAPA guy looked awful blank.

Not as blank as the dealer. I was amazed. a few minutes later with a microfiche and it was "Oh... I never knew that. No, we don't have one. Want me to order one for ya?"

 

[TurboTahoe]

Great Clipper,

Thanks for the info!

-Rob

 

[bk95td]

Great tip, Thanks The link to the pdf file is damaged ,it said.

 

[doober]

Great find Clipper, I often wonderd where that filter was actually located. I will have to check the condition of mine next time I change the filter. Can one just grab it with a needle nose pliers and pull it up and out?

 

[great white]

I wouldn't say "new", but certainly important...:thumbsup:

 

[Clipper]

Great find Clipper, I often wonderd where that filter was actually located. I will have to check the condition of mine next time I change the filter. Can one just grab it with a needle nose pliers and pull it up and out?

I just used two fingers, "claw-style"...but like I said, there may be some hardened sludge on the centerpost that you have to scrape off...it's a snug fit. I tapped on a deep socket to push it back on, but it went on much easier than it came off. I also used a little mirror (the one in the first pic above) to make sure it was seated properly.

ROFL... yeah, more than one of us has had that conversation ... mine was with a dealer, because the local NAPA guy looked awful blank.

Not as blank as the dealer. I was amazed. a few minutes later with a microfiche and it was "Oh... I never knew that. No, we don't have one. Want me to order one for ya?"

BTW, the dealer won't sell you one; they want to sell you the whole fuel manager for two hundred-something bucks. That's all that shows on their fiche...there is no breakdown of the filter/manager, not even seals and o-rings.

I found one on SS Diesel supply, they wanted ten bucks for it.
ssdieselsupply.com/product_250_Fuel_Strainer_Inside_Fuel_Filter
Luckily I have a Stanadyne dealer here in SD, (two, in fact; big Navy town with a major shipyard.) They only wanted 2 bucks for it, but it had to come overnight from LA, which was another eight bucks, so...there's yur ten bucks anyway. LOL...

Great tip, Thanks The link to the pdf file is damaged ,it said.

Hmmmm...it's opening just fine for me...??!!
There is no exploded parts view here, just a list of the parts, seals, etc.
SS Diesel has pics of all the parts and seal kits:
ssdieselsupply.com/search.html?action=search&keywords=fuel+filter


hot link to non site sponsor edited

 

[JiFaire]

The damn things are hard to come by up here.. the dealer tried to order me one, but couldn't get it. One of my buddies from Ontario ordered up a whole handful from one of HIS buddies in Michigan... and send us westerners a couple of them for Christmas presents.

 

[dangerousdave]

I'm wondering what the scum was / is.
Petrified algae? bad fuel? How was the fuel pickup "sock" in the tank?
I'm Looking to prevent this crap from depositing.
Did you use cleaning additives ever?

Ideas?

 

[buddy]

He ran like B100 for a while, most likely the cause, and letting it sit. I pulled the one out of my 94 about 18 months ago and it was spotless.

 

[Clipper]

I'm wondering what the scum was / is.
Petrified algae? bad fuel? How was the fuel pickup "sock" in the tank?
I'm Looking to prevent this crap from depositing.
Did you use cleaning additives ever?

Ideas?

Yeah, as Buddy mentioned, I *did* run B100 for the last year or so...but the problem (bucking on hard acceleration) goes back WAY further than that. It just finally got bad enough to shut down the motor during a trip to Vegas (fortunately, fairly close to home, on the way back...~70 mile tow. Thank God for Triple-A.)

The truck has only sat for the last 6 months or so, and this problem was *why* it sat. :mad2: Before that it was my daily driver, and it soon will be again. Right now I'm rewiring the VO system and adding a boost gauge; should be done by this weekend. And I also have a boost controller from Heath that I'd like to get installed while it's down.

And BTW, the VO does not pass through the stock fuel filter...I have a heated Davco for that. The VO a whole separate system, right up to the IP and engine return lines. There *may* be some cross-contamination when I'm switching over, but I am VERY conservative with the VO. I never switch over until it is up to at LEAST 150 degrees, and I have a LONG purge cycle, so if there *is* any cross-contamination, it's more likely diesel going into the VO tank.

So it's hard to say if the fuel is the problem. I'm planning on continuing to run B100; it actually runs WAY better on it. I'll just keep a close eye on that strainer.

I've owned the truck for ten years, and religiously run Stanadyne blue when I run diesel. It's possible the Stanadyne blue reacts with the B100 somehow...??!! Or maybe the new ULSD?

I also do oil samples with Blackstone every 15k miles, so if there was something funky going on with the fuel, it would likely show up in the oil. For example, when I started running WVO, sodium levels in my oil went up (supposedly from the salt in WVO.)

The tank sock was clean.

Bottom line is, it *may* be something that I am doing wrong, or the fuel that I'm running, but IMHO, I think it's worth it for everybody to put "checking the strainer" on a your regular maintenance schedule...and maybe even keeping a spare on hand. That's basically why I wrote this dissertation...!! :rolleyes5: That, and all the fame and fortune I get from writing it...! ):h

--Clipper

Incidentally, in case anybody's interested, below is the wiring diagram I drew for the aftermarket stuff I've added...primarily the VO system and gauges.

 

[buddy]

Thanks Clipper, lots of good info.

The terrible part is that the last ditch fuel filter screen is POST filtering. So the fuel should have been filtered by then. So there was something funky with yours, very funky. The fuel heater is right on the center of the inner shaft, wonder if it was overheating, plus looks like you still have that corkscrew thing around it that I would remove, which would transfer more heat to the wall of the shaft.

Not sure how that happened unless PO ran something funky, like french fry oil in his fuel, and perhaps changing filters without purging the setiment on the outside first, and cleaning the bowl.

 

[3bals]

I'm just a little confused. Maybe I read it wrong, but you talk about running B100 then talk about a WVO system. Which is it? They'er two different fuels.

 

[vail426]

Why would the screen be after the filter? It certainly cannot filter as well as the paper element. So what purpose would it serve?

 

[buddy]

For people that put new filters in without flushing the old crap out or cleaning the bowl. Contaminant and sediment can set on the outside, pull old filter out, all of it floats around in fuel into center, place new filter with crud inside the paper element.

 

[Green Machine]

I'm just a little confused. Maybe I read it wrong, but you talk about running B100 then talk about a WVO system. Which is it? They'er two different fuels.

Maybe he runs both B100 and WVO? Run B100 during startup/warmup and pre-shutdown... and WVO after system is warm? I dunno :mad2: lol.

 

[great white]

For people that put new filters in without flushing the old crap out or cleaning the bowl. Contaminant and sediment can set on the outside, pull old filter out, all of it floats around in fuel into center, place new filter with crud inside the paper element.

Or if the element deteriorates and starts coming apart.

Additionally, sometimes manufacuring proccesses leaves a few...ahem...."suprises"... in the media...