Eratic behavior from an 85' 6.2 (more below) requesting help please (Two vids in one)

[nycxjeremyy]

Holy cow…
That differential is probably really low on oil.
The input seal is what is leaking- you have to have the rear end fully set up for replacing that.

Degreaser- clean it all off to start. Remove fill plug & top it off - keep checking it VERY OFTEN until you can learn it all & buy the tools to diy or take it to a shop.

Some people learn it easy and do fine- for others it seems to be rocket surgery.

Imo- again age of truck- you might open it up and find way more than just seal needs replacing. My thought it when doing input seal to do the axle seals at same time. Replace any questionable bearings. Get it all new condition again then you can ignore it for the next couple hundred thousand miles.

YouTube videos get you a decent understanding of the task.

Copy sir, I'll clean/degrease it and see what I find down there

 

[dbrannon79]

that amount if drain back is find and not too much to worry about. start it up and see how the air situation is watch it as your first starting vs leaving it run for a bit.

 

[MrMarty51]

Get back under the truck.
Look at the fuel hoses between the tank and the lift pump.
If there are hose clamps attaching hoses to fittings. Start by tightening those.
See what the air intrusion then does.

 

[nycxjeremyy]

Get back under the truck.
Look at the fuel hoses between the tank and the lift pump.
If there are hose clamps attaching hoses to fittings. Start by tightening those.
See what the air intrusion then does.

Got these so far

 

[dbrannon79]

I don't think there will be any visible hose connections for the fuel lines since he has a mechanical fuel pump on the passenger side of the engine. ifaik there will be two rubber hoses coming off the top of the fuel tank that have threaded connections with o-rings that connect to the two steel lines (supply and return) then run up the frame rail with metal tubing all the way up to the lift pump. there at the lift pump there will be a short section of rubber hose with clamps where it connects to the lift pump. this short section of hose might be where the air is getting in at. if not, then it will be the hoses on top of the fuel tank with the o-ring connections.

 

[Will L.]

Ignore the air trapped from sitting overnight.
Any bubbles traveling when running is the thing you watch for, and you have it in spades.

The metal lines don’t look horrible from pics I can see. But be suspicious of them.

most trucks run 3/8 from tank to filter, then 5/16 filter to ip. Bumping up to 3/8 is a good idea. The cone on the end of the ip can be removed then drilled & tapped, but carbide tools are needed. Easier is buying the ford part- their db2 have 3/8” line factory. If you don’t want to mess with the cone at this time- you can buy the T for the fuel pressure gauge as 3/8 on one end. But with the mechanical lift pump- it depends which system you have what size it is . Sorry- can’t id exactly what size you need everywhere.

Might be better to remove it all- then you can measure the length needed and buy appropriate amount.

I would tackle one task at a time.

You might need to buy replacement tank straps when dropping the tank- no way to know what condition they are in - but soak with your favorites penetrating oil before starting.

 

[nycxjeremyy]

Well, currently at a friend's house who's father was in the Army, and as a result he worked with 6.2s, gonna tackle it now

Started as bad as it normally did, actually drove smoothly but every time let off the throttle it would begin to surge.

We have a jack and stuff so we can lower the fuel tank to replaces hoses there, we'll be digging in EVERYWHERE

(How it drove: https://photos.app.goo.gl/CnBfQPymP44tghzi9 )

 

[nycxjeremyy]

Tightened a few clamps, here is test result 1

(Photos of the area where we tightened the clamps aswell)

Test 1: https://photos.app.goo.gl/cjkDbNTrP7t4MG2P6

 

[nycxjeremyy]

Update:

So much damn air

New video by Jeremy

photos.app.goo.gl

 

[nycxjeremyy]

Update:

So much damn air

https://photos.app.goo.gl/HC1q9okr6YAyCL1R8[/URL

http://

We're stumped at this point, what are the odds it's the o ring behind that line (clear one)

2 new items by Jeremy

photos.app.goo.gl

 

[ak diesel driver]

Just start replacing rubber with clear until you have one the doesn't have air in it. My bet is either the sending unit or the fuel pump.

 

[nycxjeremyy]

Just start replacing rubber with clear until you have one the doesn't have air in it. My bet is either the sending unit or the fuel pump.

Looks like this now sir

 

[dbrannon79]

The air is getting in behind the IP it won't be the seal on the clear hose. go get you some 3/8" and some 5/16" clear hose and start replacing with it. start at the lift pump. I'm willing to put my finger on one of the hoses at the lift pump or at the tank sending unit.

 

[dbrannon79]

it's not gonna be after the lift pump (between the LP and the IP) if it is, it will leak fuel unless the LP is not working.

post a picture of the lift pump from underneath for us. there should be a short piece of hose coming from the steel line on the frame connecting to the lift pump. that hose will be suspect.

 

[ak diesel driver]

IIRC there's only two sections of rubber hose before the LP. The one at the LP and one longer one at the fuel tank. If you have a hole rusted through anywhere it's most likely coming out of the tank. I wouldn't even bother with the return side just yet. Also just because you replaced the LP a year ago it doesn't get a free pass.

 

[nycxjeremyy]

IIRC there's only two sections of rubber hose before the LP. The one at the LP and one longer one at the fuel tank. If you have a hole rusted through anywhere it's most likely coming out of the tank. I wouldn't even bother with the return side just yet. Also just because you replaced the LP a year ago it doesn't get a free pass.

This is the underside, photos of the lines and the current air buble.

We sliced the end of the rubber hose and tightened down the clamp after it

The current air buble pictured is all that after tightened the hoses down

If this doesn't work, we will drop the tank next

 

[nycxjeremyy]

Good Lord

New video by Jeremy

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[dbrannon79]

Those two sections of hose one at the lift pump and the other at the tank are cheap enough I would go ahead and replace them.

if you drop the tank, pull the pickup tube/sending unit out and inspect it as well. there is a chance it's rusty and could have a pin hole on it. eliminate the sock filter on the end while you at it too. then when you replace the hose at the lift pump you can loop some extra hose where you can install a inline clear filter there to catch anything before it goes into the lift pump.

again not knowing if the lift pump is actually supplying fuel pressure can be the source of all your problems.

 

[nycxjeremyy]

Those two sections of hose one at the lift pump and the other at the tank are cheap enough I would go ahead and replace them.

if you drop the tank, pull the pickup tube/sending unit out and inspect it as well. there is a chance it's rusty and could have a pin hole on it. eliminate the sock filter on the end while you at it too. then when you replace the hose at the lift pump you can loop some extra hose where you can install a inline clear filter there to catch anything before it goes into the lift pump.

again not knowing if the lift pump is actually supplying fuel pressure can be the source of all your problems.

Copy sir,

One thing I'd like to add is that it does not act up/surge when moving, it's only at idle

My friend the ex Army MX (mechanic) guy literally stopped to go in reverse, and as soon as he stopped it reved to max RPMs before dropping and repeating the processes, we barely pulled in before parking and shutting it off in a hurry

 

[nycxjeremyy]

Let it sit while we went to the store, i caught up doing this

New video by Jeremy

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