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Fuel Issue. I guess.

bradshawtech said:
I am guessing plugged fuel filters.

Even if you changed them recently, I would change them again.

Another thing to think about, how cold is it getting there? Is there a chance that the fuel is summer blend and might be gelling?

Pull the line off as it attatches to the IP and crank to verify there is fuel moving to the IP.
Click to expand...

Ding Ding.

Sort of, primary fuel/water was pretty filthy considering I changed that at the end of June this year. There was gelling, had some yellow colored mayonnaise in there. When I poured it in a bottle, the fuel looked pretty clean, a little too dark yellow perhaps, and it all smelled like paint thinner.

So I bypassed my primary, took off the secondary that I changed I guesss about 3 weeks ago, looked ok, can't see inside that one so well, but no chunks of gel, or obvious signs of dirt, I couldn't bypass that one easily, emptied it, put some leftover diesel kleen in there, swirled it around and dumped it, put it back together and ran it. Idled nicer, let it run for 20 minutes or so, tried to test drive it, sometimes it sounded even better yet, but still wanted to die ocassionally, well it did die once. The issue with WOT and it just dying out seems to be better. I think my main issue now is air in the system, but with the lines being flared, hooking a hose (how I have the primary bypassed) isn't going to work, so trying to figure out how to bypass the fuel line to the tank.

I'ma go out and get two new filters, fill a can full of fresh diesel, put some diesel power anti-gel or something in it, pour it in the tank, and run the engine for a while to let it circulate.
 
So, got new filters on, mixed up some anti gel additive into a gas can and poured it in, primed the system.

Read this great write up clicky

So I put a clear fuel tube on the return off the IP. Blew some air (5psi) into the return, immediately saw a leak right there where the passenger side injector returns Y's right near the lift pump, fixed that. Heard another leak, it's right on top of the fuel tank, so guess that has to drop.

Started it up to run the bit 'o fresh fuel with anti-gel through the system, started right up after I bled it with the compressed air, ran for a minute or two then just bam it died. Bubbles in my newly installed clear tubing. Kept trying to start it up and run it, acting like before, and of course, the surging and dying coincides with bubbles.

When it does die and all the air/fuel settles around, all the bubbles comes from the return side of the clear tube, not the IP side. Guess I'ma drop the tank and find the leak and go from there.
 
Might be a rusted sending unit nipple for one of the fuel lines,feed or return...one pinhole is all it'll need to make it act up..

My truch had the original 3/8" steel fuel feed line from the tank to the filter and it was getting very flaky and one day I saw it was wet bear the cab mount where it runs up to the filter--I had a 10 foot length of 3/8" copper tubing hanging around so I decided to use that instead ,I used a short rubber fuel line to join it at the sending unit and I bent it and flared it to fit at the filter mounting base...my truck used to surge sometimes after a hard acceleration at times or feel like it had run out of fuel,but would recover,or start back up once I coasted into the breakdown lane,so maybe it was getting air in thru the rusted area that was weeping..
 
So, after much work I have access to the top of my fuel tank. Damn homemade abomination of a reciever hitch was welding all over the frame. Stamped with 70's something ford contour stationwagon. Had to cut it all out to drop the tank.

Anyhoo, my air leak is the line that goes to the drain valve on the tank, the valve that's on the passenger side frame rail by the rear spring hanger. It's leaking from the hard line that's part of the assembly that goes into the tank, so to fix it I'll have to replace that entire assembly.

Would that cause air to enter the system? I mean, if it's not THE fuel supply line :dunno: From what I gathered that drain valve was to remove water. It's leaking right where it connects to the assembly. Either way I'm dropping that sucker to see if I have crud in the tank.

So if this valve was to drain water, origionally this model year 82, then did the primary filter not have a drain valve for water? I mean, all the new ones do, did the old ones not? I read something about sucking fuel through the primary on earlier models (which I see they do), and pushing fluid through the primary on the later models.

Either way pricing a new assembly.


EDIT: Actually, saw a fuel tank on rock auto for cheap. On another note, the 25 gallon tanks are 2" less in height, I could care less about the extra 6 gallons. Everything I see on LMC show a 4 outlet fuel tank named diesel, for 84+, which I know is the year of the change. Can I find a 25 gallon tank, 3 outlet assembly and remove that drain valve? Just thinking of clearance related stuff for later on, also need a skid plate.

No differences in the diesel/gas tank is there, just possibly the line assembly? I'm looking at lmc for picture refrences, but there's a 25 gallon tank at rock auto for $41, or $95 depending on brand, don't know which brand is better, Spectra Premium, or Fineline. Perhaps a reason for the spectra being more, but I've always known spectra as a cheap engine dress up parts company.
 
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Guess it's the same skid plate on 31/25gal. Just the 31gallon is closer to it huh. To nix that. Just a new sending unit assembly then. As soon as I can find one elsewhere than LMC.

Or not, no one has them (so far) other than LMC or 1aAuto, and LMC's price is better. Though they don't have a 4 outlet diesel. Just 3 or 4 gas, and 3 diesel. Don't really care about that valve, and 84+ they removed it so...
 
My 82 stepside has dual tanks and both have the drain valve plumbing...far as I know the tanks are identical for diesel or gas,its the sending unit thats different,it has the water in fuel sensor and another nipple for the fuel drain and return line hoses to hook up too..it has a spin on primary fuel filter with a drain and bleeder,and no secondary filter--if it ever had one its been deleted before I got it!..

I put a 20 gallon gas tank from a gasser in my truck and it was identical to the old tank..far as I can tell on the outside anyway,and I noticed no baffles or internal differences,I just swapped the original sending unit into it..filler neck was the same size too..
 
Well removed the sending unit this morning, luckily the ring was pretty easy, no undue banging, just love taps on both tabs. Aside from that unsecure hardline for that drain valve, I still can't understand why it would allow air in the system, looking at it it's in no way connected to the supply line. Inside of the tank isn't bad, the sock was slimey. Drained the rest of the fuel out with my beer auto siphon :rolleyes: Guess I need a new one of those or name my future brews "Diesel".

Went ahead and removed the drain valve and line, so that's gone, I'l just get a regular 3 line assembly to replace mine with. Hooked supply/return to some spare hose and dumped them in my 5 gallon jug, started it up. It's fine, some air at first of course, once it went a way, a bit of miniscule bubbles when I raised the rpms, but that's all gone too. I LOVE that clear tube idea for the IP return.

I needa get some longer hose so I can tie down the jug inside the cab and go for a spin and really test it out. I cheated btw and there's an 11x8.5 rectangle in my floor now :whistle:
 
bubbles returned shortly after my last post yesterday, I would say 20 minutes of it idling. Back to finding the source of the air, something's changing when it warms up, seals, hose, something in the IP maybe is expanding with heat and allowing air to get sucked in, to take a guess.
 
You may not ever get it completely free of bubbles--my VW Jetta had bubbles in the clear return line almost always,yet it ran fine regardless...I would guess some bubbles showing might be "normal" to certain degree,but if your seeing large air gaps in the clear hose something is amiss..you may have a crack in a fuel filter housing or a o-ring not sealing properly..your sure the return line has no restrictions?..I read here about some kind of check valve in it that can screw the flow of returned fuel up and cause stalling ...

One truck a friend had that still had the factory 12V fuel heater under the intake (first one I ever saw!) had a tiny rust pit hole inside it ,it would act like it ran out of fuel when you punched it to get on a highway or pass,pull a steep hill,etc..I thought it was lucky the thing didn't ignite the fuel..(maybe it wasn't working?)..he deleted it and it ran fine ever since..and he had pulled his hair out changing the lift pump.filters,fuel lines,to no avail...it wasn't till he noticed some wetness on the valley pan that the thing was weeping slightly--slowly enough so the fuel evaporated instead of puddling up,until it started leaking worse..
 
I don't see any restrictions in the return. Today I noticed a bit of a pinch on the supply line right after the lift pump. I'm going to take care of that. I've noticed there's a crap load of cuts in the metal line patched by hoses, like everywhere. The Primary fuel filter someone screwd a hose barb in the outlet side. After the secondary filter, the outlet goes to metal, and then there's a hose on a barb into the IP. But none of them are leaking, visible wetness anyway, even with blowing air into the system.

The line I can't see well is secondary filter to IP. So I'm about to remove the intake. Which is fine I guess, wasn't ready to do that just yet, but I'm in search for a j code intake, so I'ma take that off, rip out a bunch of crap from the engine bay, then I'll be able to see those two lines better. Kinda thinking of a better location or something for the two filters. Don't think the J code has provisions for the secondary filter mounting.

Wonder if it'd be a cleaner set up if I moved both filters back under the Blazer near'ish the fuel tank somewhere. At least cleaner for the engine bay, they'd get filthy under there.
 
Thanks, but imiceman44 said he had some, just waiting for him to get a shipping price.

On a similar note, just got done taking the intake off, they put a non egr gasket on :doah: bunch of oil pooled up on both sides where the gasket's egr cover thing was.
 
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