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Fuel Issue. I guess.

MrSchaeferPants

MrSchaeferPants

1/2 ton status
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Hot Springs, AR
So the 6.2 lacked power, driving down the road, pedal did nothing. I was almost idling home with occasional grabs of power for no apparent reason. PERHAPS, unless I was imagining, my road is a dirt road, kinda wondered if the big bumps would jar crud loose and it would get a bit of fuel going?

Either way, I changed the secondary fuel filter. I changed the primary-fuel/water seperator around May or so, that thing was disgusting. Anyhoo, changed it out, primed the filter with diesel kleen, started up (and yes that secondary filter was gross too), ran fine sitting there for a few minutes, drove and bounced around and it died, sure I had SOME air left in that system from changing the filter, so though I shouldn't have to, I cracked the lines, fuel comming out.

So, now I have to floor it, crank extra long, it starts, might run ok at idle, though usually runs like crap, chugs, dies at random times. Cracked almost all the lines one by one. Still either runs ok, or chugs, decides to die for no reason.

I'm guessing air is entering from somewhere. Or I wonder if my IP is going. I'd assume if air was entering somewhere, when I cracked the lines it'd be super bubbly/frothy? The front most on each side seemed that way at first.
 
sure the filters are tight? don't you have to take off a like to get to the secondary filter?
 
You can splice in a section of clear tubing on the return line and watch for air bubbles--if there is a lot of them or it looks foamy the IP could be going bad or maybe sucking in air at the throttle shaft seals..my VW diesel had tons of bubbles and ran OK however,as long as you did not let it sit more than a week or so,then you'd have to crank it over a long time to fire it up..

My 6.2 has done exactly as you described a few times--I never pinpointed the problem,nor did I replace any filters,I chalked it up to a dose of water in the fuel passing thru,or maybe the fuel gauge lied and showed 1/4 tank when it was closer to empty and I airlocked it by parking on a hill ,and all the fuel ran to the other end of the tank away from the semding unit "sock" filter..(yours might be getting blocked with sludge if the fuel was as nasty as you say it was?)..

I added an electric pump near the tank to push fuel to the stock lift pump on my truck too,and that may have decided to take a vacation or get gunked up,then come back to life too..one day the truck died on my way home and I couldn't hear the electric pump running or feel it vibrating touching it,and I opened the top bleeder on the fuel filter and nothing came out,not even air..

But after I got a gallon of fuel and dumped it in,the fuel shot out of the bleeder when I turned the key on,so either the tank was too low on fuel,or the pump stopped working,then came back on when it cooled off or maybe it was blocked up or something--its worked OK ever since that day as long as I leep the tank over 1/4 full--it did act like it was going to run out of fuel one day when I let it go closer to 1/8th of a tank..soon as I added fuel it seemed OK again..

I have tried draining my tank thru the factory siphon valves and see no water come out too,if there is any gunk in the tank its in the form of tarry sludge if anything..I assume my gas gauge is losing accuracy,I used to run it below "E" without ever having it act like it runs out of fuel..

Must be the season for 6.2's to start giving greif?..

Yesterday it was 16 degrees out with a 40+ mph wind chill..my truck started hard,but did fire up,and it sounded like all 8 pistons were too small for the bores the whole 5 mile trip I took it on..

Its always sounded like a stonecrusher,but lately I hear a disturbing woodpecker tapping on a hollow log type of noise when I'm pulling a slight hill or cruising with light throttle..seems to be worse at times when its warmed up--starting it cold,you hear no knocks like most old engines with worn mains or rod bearing will have until oil pressure builds up,and the oil pressure seems the same as it always has been,well over half on the gauge at idle and it'll almost bury it at higher RPMS..

A year or more ago I had a glow plug break while I was driving ,so I assume the piston in that cylinder got some punishment when it got crushed up in the combustion chamber--it tapped all the way home (3 miles) till I floored it a few times when I was close enough to walk the rest of the way home if she blew up..it quieted down,like it blew it out the exhaust,but since then I have a noisy tappet noise after a cold start that eventually fades away after it warms up fully..probably bent a pushrod or some valve train component?..sounds to me the noise I hear when its hot is more of a piston slap or maybe a loose bearing type noise..I dont think its an injector making a knock,but who knows..it seems to run OK,no worse than it ever did..:dunno:

Strange thing on my way home yesterday,I went over some rough road and the truck bounced up and down to the point it almost got air,and the engine suddenly quieted down a LOT,like the usual clatter dissapeared completely..like maybe the oil in the pan got sloshed up onto the crank and camshaft..

I'm hoping it hangs together thru this winter--if it dont its debateable whether the truck is worth the effort to put another engine in it..
I hate to fix everything else it needs ,then have the engine crap out..I'm not up to doing an engine swap either any more,especially this time of the year..


If I did re=power it,I would probably not want another diesel really,I have my 85 Suburban with a 6.2 still,one is enough..,and in a way I would prefer a gas engine for what I use the truck for..a straight six would be a good candidate,the power and torque would be about the same as a 6.2 is-- IF you could find one thats cheap around here,they are scarce,even a carbed V8 is like a hens tooth to find here lately for under 300 bucks..most you cant hear run and have sat in someones shed for a decade if you find one too..

It could run making this noise for another few years--or pop tomorrow..I hate having to trust a vehicle thats in that condition..bad enough I'm riding on mis-matched nearly bald cracked old tires,and it has several other "issues"--never mind worrying about it tossing a rod or something..:mad:
 
80' 427 said:
sure the filters are tight? don't you have to take off a like to get to the secondary filter?
Click to expand...

Filters are tight as far as I know :dunno: I have the round style primary BTW. I removed the two bolts on the intake mannifold that holds the filter housing on, it was enough to slip the filter down there w/o having to remove the lines.

Massboy said:
How about your lift pump?
Click to expand...

What about it? No fuel leaks. As far as air getting IN, I have no idea, I know every part of that fuel system air could get in w/o fuel getting out. I'd imagine if it was bad I'd be getting nothing. Usually what I see on the 6.2s is the rod breaks in half, could check for that.


One thing I am noticing, like D4M said, my primary filter, nothing comes out of the upper bleeder, or bottom drain, but if I unscrew them, air will get in and kill it, it takes a minute or so. Makes no sense to me, with it running I should have fuel coming out, and enough fuel where there shouldn't be a chance of air coming in.

I guess whatever screen or sock is in my fuel tank could possibly be plugged and nasty too. Guess I'd have to drop the tank or find some kind of flow gauge to put between the tank and lift pump or P. filter.



And the chug chug and roughness is only at idle. In park, engine reved it seems ok. Though hard to tell with my obnoxiously loud squealing Alt :)
 
Far as I can tell my truck never had a secondary filter under the intake,or someone deleted it...maybe I should take a closer look to be sure one isn't hiding under the intake,but I am pretty sure there is just a rubber hose going right to the IP..

I have the round spin on primary filter with a 33123 Wix on it ,and its old and I really should change it..

I assume my original right side tank has some crud in it,because it had developed a leak a year or so ago on the front corner of it--I stuck a speaker magnet to the spot and it soon dried up and no longer weeps,so I'm assuming some rust and goop are forming a clot to keep it from leaking..
I had got a good used tank for the drivers side and swappin in my original sending unit and installed it--but never got around to swapping all the hoses off the right side tank to it yet..I should do it soon,but have procrastinated doing so (BTW,my sock filter on the original tank looked like new,even after it sat empty the 10 years I have owned the truck)..not so sure the tank I'm running on is the same though..

I did run new 3/8" copper tubing from the fuel tank right to the fuel filter on the firewall,that seemed to improve the cold starts,as the original steel line and rubber hoses were crispy from rust and all crackled..I did that after the day it "ran out of fuel" in case it was sucking air there,but it did it again when I ran the tank down to 1/8TH as I stated before,so that probably was not the cause..

I thought about doing a "purge" like the sticky post above,then change the fuel filter,but I'm leery of making a problem like yours,or loosening some carbon up in the cylinders ,if that might be whats making the noise I'm paranoid about..sometimes its best left alone..

My engine sometimes misses and lopes at idle too,its probably one cylinder is low on comptession and isnt producing enough heat at idle to ignite the fuel every time it should fire maybe..you can detect a little vibration sometimes too,like one isn't putting out the same amount as the other cylinders are..could be a valve sticking too maybe..as long as it dont stall at stop signs I dont worry about the occosinal misfires much..

Diesels are great when they run good--no spark plugs,distributor,carbs,or plug wires to replace or mess with..but when you start having injector pump troubles and fuel problems,cracked cranks,blown head gaskets,and find out they are very expensive to have fixed or replaced,I am ready to go back to a gasoline engine..

I like my 6.2 as long as they run good,no doubt this one plows better than any gas V8 truck I had previously..but I hate changing glow plugs at 100 bucks a pop,needing two batteries,having to plug it in for it to start,and the noise and vibration,and wondering if and when it'll grenade on me..the fuel mileage aint all that great IMO either,I'd rather get 5 mpg less and pay less at the pump in a way..
 
Sounds like your lift pump may have failed. Check your oil for diesel fuel contamination!
 
kennyw said:
Sounds like your lift pump may have failed. Check your oil for diesel fuel contamination!
Click to expand...

That's something I thought about after Massboy posted. If it's leaking, check the oil, that or the push rod.

So symptoms. While driving (before I did the secondary filter) would start great, idle great, had no power, pedal did squat. Now, hard to start, crank for a while, have to floor it to start, idles like crap, can't drive around the yard w/o it wanting to die. But in park, revs up, will hold a higher rpm fine.


Oh and also, seems like the exhaust was hella smokey. It was dark last night, couldn't tell/remember if it was before it was warmed up, usually right before/during it dying. Color? No idea, it was dark. Coulda been grey, light gray, could have been my headlamp making it that color :D
 
Sorry,
I thought my statement was obvious and was meant that I thought the pump was bad. To me it sounds like your lift pump isn't pumping. It doesn't have to fail to the point of leaking into the block but it can just stop pumping. Pull the red wire off the IP and open the filter vent. Turn the truck over and it should pump out plenty of fuel. If it doesn't, your LP is gone. My brother's dump did exactly the same as yours. It will run as the IP will pull fuel but as the IP gets worn it will pull less and you will get the run conditions you are having.
 
That's the plan, haven't had time recently, and now I'm off work half of yesterday and all of today, but that's cause we have freezing rain covering everything. I should of done it this past weekend :doah: Guess I could man up and bundle up :D
 
I got a friend who's heater core let go this past summer. I told him to replace it but he just bypassed it saying he would get to it. Now it's cold and he's bitching because he is too cold! Procrastination gets you nowhere.
 
Been there--done that!...I'm great for mickey-mousing and bypassing things to "get by for now" and "now" ends up being years..:rolleyes:

One car a friend had,a 70's Volvo,had the heater core fail,and we bypassed it,it was in august when it failed..by October he was complaining about the lack of defrosters,and he decided to go to the library to read up on the procedure to replace it..he decided not to replace it--it seems Volvo puts the heater core in the center of the car first--then builds the dash,console,and the rest of the car around it,and it ALL had to come out to replace it (or SEE it!)..

A few weeks later I saw him and he says "hey--look how I fixed my heater!"..
I look in the car and see this plywood box,I thought at first it was a home stereo speaker--it had two speaker grills ,one on each sice,and two hoses like you'd see on a vacuum cleaner coming out of the back ,that dissapeared under the dash...it had a house type light switch on it..I just stared at it and said "how does it work"?..."GREAT!--get in,I'll show ya"..

He flips the switch and on comes a blower fan going about 6000 rpms,that he got from a GM truck and mounted on the box..he ran two heater hoses thru the firewall ,and used a heater core out of the same truck he got the blower motor from,and put two ball valve in line so he could shut the hot water flow off when heat was not needed...the two vacuum cleaner hoses went to the defroster ducts..("What a bitch of a job getting those things hooked up,he added!")..

.it took up a good amount of space on the console,made sitting in the car pretty uncomfortable..though it did throw a ton of heat,looked decent enough,and would have been ideal for a rear heater in a bus or blazer--I said "wouldn't it have been less work and faster to just replace the original heater core?"..

"Hell NO"!..."This is ten times better!--I can replace the heater core in 15 minutes now,if it ever needs one--the blower motor too!--the originals are buried deep in the dash,screw that job!..":thumb:...

Some guys are like that--they'll take the long way home and say its faster..:rolleyes:

A few days later his sister borrowed the car,and when she flipped the heater switch on,the blast of hot air blew the glowing head off her ciggarrette,and it went under her dress--and quickly started a nice glowing seat fire..luckily she had a can of soda to put it out with,it ruined the seat cushon and her dress,and burnt her leg pretty badly..:doah::haha:..she never asked to borrow his car again after that!..
 
Oh it wasn't procrastination, I aint got the time, besides I Gotta order parts. Last weekend it was go go go everyday. I'll at least take it off today and see what I can figure out. No one stocks the pump here anyway. Our little 'ice storm' shut down town too, so might as well order from rock auto and wait for it to come in.
 
My jerry-rigging and mickey-mouse "temporary" fixes stem not from a lack of time,but more like lack of ambition to lie on my back or bend over working on the truck for hours and suffering the consequenses afterwards...

On a vehicle thats borderline worth fixing at all, dont help either..most people that had a truck in the same sad shape as mine would probably tend to cob it together with bailing wire,duct tape and zip ties too--or simply scrap it..

Once the laundry list of things needing attention gets to a certain point,I get the "why fix it "right" when its on its last legs anyway?..I only keep the stuff needed to be safe and pass inspection in good shape,like brakes,steering components,etc..I see no point in swapping a motor into a truck with a frame thats getting punky and thin in places,you have to draw the line somewhere..
In my youth I would weld the frame up and do it anyway,now I'm getting too old and discouraged for that much work on an old POS..
 
It's out, braved the cold. Rod's fine. Ordered a new pump and gaskets from rock auto. Pretty much all I've read says the same thing, open the fuel filter bleeder, if it kills your engine, lift pump is bad. Tried pressing the lift arm, holding my thumb over it, but hands were numb, and gloves kinda don't work trying to cover the inlet tube. It was kinda hard to press it while covered, but then again it's hard to press regardless.

Either way, couple bucks. Hindsight and all, don't know why I didn't remove the line either off the pump or the secondary filter and see if it spat fuel out :dunno: Ain't worth putting it back together to see that :D

Also wondering if it's a gasser fuel pump. I'll compare when mine comes in.
 
Not done yet, but got my fuel pump and gaskets in the mail from rock auto yesterday, and side by side, yes they're different.

Man had to be the most PITA hardest time ever on a fuel pump. Everything that could fight me, did. But it's in, fired it up. Started pretty easy considering the air in the lines from doing the pump. Idled ok, but didn't let it run for long, also doing a t-stat, so the coolant is all drained. Gunna pick one up tomorrow, get that done, hose back on and filled, and take it for a ride.

IMG_20131214_094455.jpg

IMG_20131214_094455.jpg
 
It's a no go. Put everything back together, started it up pretty fine, idled good once it warmed up (chilly this morning). Ran for 5 minutes and died, started it back up easily, and it idled good for 15 or so minutes, as soon as I drove off I knew something wasn't right. Drove 200 foot or so to my spigot to clean up the engine bay and it was stumbling. When I was done washing it out, went for a short trip down my road and it chugs and wants to die unless I keep my rpms up a bit. Died on the turn around.

At first when I romped on it it sounded real good, clean and strong, but quickly it was back to the old problem pedal to the floor, rpms slowly drop to idle speed, then died. Then I had to crank for a while to start it back up, eased it back home. I think the proper fuel pump helped, probably more flow? For those few seconds of WOT.

Leaning towards an air leak problem, tomorrow I'm going to disconnect the supply and return right at the engine and put it in a jug to rule out or confirm the lines and tank. Maybe it's something easy like a pin hole in a line, maybe there's crud in the tank :dunno: The strange thing is sometimes it idles just fine, then chugs and dies. So maybe tank crud.. I dunno. Frustrating.
 
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.
 
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