7.3 idi fuel filter light but worse

cragenj3

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Fuel filter light came on; truck died pretty quickly after. On the road, so took it off dumped it put it back on, primed it, tried to go. Nada.

Ran the batteries dead.
So I got a tow and a pull strat; took 2 pull starts to start and ran rough, some injectors popping, heavy whitish smoke.

Been messing with it... New filter, new electric pump, even did the return line orings today, I think bumping it caused those to goof up.

So now I've got no visible leaks... I can turn it to WtS, go prime my filter at its Schrader, go in and start it right up, runs nice for 5 seconds then Fuel Filter light comes back on, and engine begins it's constant stumble and spitting out smoke, almost like running on 7/8...but every hardline is bled up to the injectors.

If you shut it down and go check at the filter Schrader, it indeed has air in it, couple depresses and it's primed back up.


So basically, there are no visible leaks, the return line kit is new, filter is new, epump is new.... So, what, do I have an injector sticking open?

It starts right up, but will die in a minute of driving and the filter will be completely empty and new fully reprimed, but there are no more leaks.
 

Clb

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Yer sucking air.
A leaking injector will usually just relieve the line pressure.
I'm not sure if it could back bleed air past the i.p. though.
 

cragenj3

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Yer sucking air.
A leaking injector will usually just relieve the line pressure.
I'm not sure if it could back bleed air past the i.p. though.
Sucking air from where, my man?

My return caps and lines are all new, less than 6 months... My filter is new... Everything is Teflon taped, even.

Think I'm sucking air in my tank?... it primes quick and easy with the Schrader...... After the epump is filter after filter is hardlines and returns, the returns are new, hardlines don't leak and are useable for bleeding; ip has no leaks... Seems like nothing downstream from the filter would suck air, per say, it'd leak fuel cuz epump...

Nothing leaks with just epump going... Nothing visible leaks with it running... Just somehow the filter is losing fuel faster than the epump 1-3psi can fill it..

No leaks between epump and tank, nothing in the foot from epump to filter..

Guess it's just gotta be my hard or soft lines arent leaking fuel but leaking air, ey?
 

lotzagoodstuff

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You are pulling air in from some leak in fuel system. If you want to verify, do a quick search on "clear fuel line" and you'll get an idea of how to install a clear plastic line so you can see the bubbles from the air intrusion.

Last question: what's your fuel gage reading? Might be as simple as the notorious shower heads that break off and cause running out before your tank is dry issues.
 

cragenj3

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You are pulling air in from some leak in fuel system. If you want to verify, do a quick search on "clear fuel line" and you'll get an idea of how to install a clear plastic line so you can see the bubbles from the air intrusion.

Last question: what's your fuel gage reading? Might be as simple as the notorious shower heads that break off and cause running out before your tank is dry issues.
Well I've got clear b4 the epump, which has no air.

Guess I need it after; I've got new return kit coming tomorrow cuz it's only $30, I mean that's all there is, if it's hard lines the diagnostic for that is to do the returns brand spanking new first, and if you've still got it then its hardlines, haha.
 

Jesus Freak

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Yeah, there's air in there. I have old school glass fuel filters on my trucks without filter elements in them on my two trucks so I can watch for bubbles. I'm an alternative fuel weirdo so I'm over the top.
 

Clb

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You are pulling air in from some leak in fuel system. If you want to verify, do a quick search on "clear fuel line" and you'll get an idea of how to install a clear plastic line so you can see the bubbles from the air intrusion.

Last question: what's your fuel gage reading? Might be as simple as the notorious shower heads that break off and cause running out before your tank is dry issues.
This^^^
Search air intrusion.
You can have it WITHOUT any external fuel leaks.
Oh and I won't tag in the infamous facett horse, yet :sorry:
 

Jesus Freak

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This^^^
Search air intrusion.
You can have it WITHOUT any external fuel leaks.
Oh and I won't tag in the infamous facett horse, yet :sorry:
Oh come on!.....its been too long since you gave us the facett horse!
 
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cragenj3

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Update.... So I swapped out the return caps and oring, all the hoses and clamps...tried hardlines with and without Teflon; they bleed fine.

Put 3/16th clear between the IP and the drivers forward return line...no air intrusion.

So perhaps I did have air to begin with but now it doesn't seem like I do... However, it does faster now, on seconds, throttle in or out...and if I shut my epump down right as it dies and go check my filter ive got good fuel flow, no air.

So...I don't know how I've managed to go from fuel filter light and a rusty filter...to leaking returns...to 2 bad IP seals...to now my fuel system is airtight and I'm dying anyway.

Glow plugs and controller are new OEM.
It starts right up, every time. If I cycle GP a few times the light will lessen in duration indicating preheated plugs.

Sigh
 

cragenj3

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I guess I am a little lower pressure than I should be by the time it dies.

The fuel heater is new, o ringed, and gasket makered just in case..works good.
The filter is on more than hand tight; the inlet and outlet are tefloned; everything at the filter body is tefloned; the sensor, the Schrader, and the capped off return.

maybe the weird orings in the inlet and outlet...but you'd think I'd see bubbles, since my epump goes into the filter...and a hardline comes out to the IP...and my only return is off the IP to the driver's front injector cap..but I've got clear hose and no air.
 

Jesus Freak

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The aftermarket return caps are prone to leaking, don't throw your old ones away.
Maybe it is a fuel pressure issue, but it really appears your sucking air. You have to start disconnecting things back towards the fuel cell and connecting what ever you disconnect to a bucket of fuel. And make sure you got fuel in your tanks, there's a chance at having pinholes in the pickups.
 

cragenj3

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I had kept my OEM caps and just did vitol 111 orings or whatever 3months avo...but pulling them off to do orings again my OEM caps finally broke at 218k odo..so gotta do what I gotta do; you'd think an air intrusion would bubble in the clear back toward the IP yeah? They were pretty high quality reputable new caps, don't remember brand but name brand.

My experience with return system leaks is that when I go out there in the morning, an air intrusion after the IP will have drained my caps and my clear hose, so will know more in morning I guess.

Must be a supply issue I guess. Tank selector is new; gauges aren't great; swapping between a half front and a full rear takes my gauge to 1 1/2 tanks of fuel, haha...all those rear lines are new actually; too... Except the rear tank as I couldn't fit in there.

I guess I'll fill my front tank up tomorrow and try running on that; maybe my rear just junked out.

Maybe my front ran out; the sensor said hey filter is empty, so I swap to rear...prime filter, start die. Swap filter, prime, start die. Dead battery, bump start and rev it up tryna force unclog and blew out all my seals...and maybe its just the rear tank pickup or something left.
 

Clb

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Not sure air intrusion is the cause of the engine dieing going down the road though...

Btw
White teflon is not fuel rated.
 

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