# 518 fuel issue



## CanopyGorilla (Feb 24, 2018)

Wondering if anyone on here can help. I've got a 1994 cat 518 I've been having some issues with. It starts and runs fine, but under load it starts to act like it's running out of fuel or bogging really bad. We did have a bad injector and replaced that.


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## northmanlogging (Feb 24, 2018)

Air in the lines?

Clogged filter.

weak pump, lift or injection.

being winter, could be as simple as a little bit of water in the system freezing and clogging filter, or fuel gelling up.

My ole Deere has fairly consistent fuel issues, usually its a cut or pinched fuel line somewhere. So it gets plenty to idle and do minor work with, but as soon as you need more fire it runs out, never dies all the way but runs like poo poo. Thankfully I think most of those issues are behind me now.


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## InfiniteJest (Feb 24, 2018)

See you're in the same area as me. Did the issue just start with the bad cold we had last week?


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## 46 Poulan (Feb 24, 2018)

Hey-- Is that a 3304 engine--Should have about 30 psi fuel pressure at full throttle. As stated could be a restriction or suction leak betweeen tank and transfer pump. I am a old cat fuel systems mechanic. could be a lot of things depending on the type of injection pump you have. Talk to me.. David South west Ga.


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## Skeans (Feb 24, 2018)

Like our D4H TSK there's a screen in the fuel hard lines in one of the fittings you might take a good look for one.

Sent from my Pixel XL using Tapatalk


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## CanopyGorilla (Feb 25, 2018)

The issue started when we bought it about 2 months ago. Figured out it had one bad injector and replaced that. Also replaced the primary fuel filter about a month ago. Took some cold and running bleeding after that but I had it up to power for a few weeks and then yes. Issue did re-start with the cold. I just don't have the mechanic background a lot of guys do, but buying a skidder has sure forced me to learn. So basically I know the issues it "could" be, I'm just not the best with figuring out which one it is with out starting to replace things until it works. We did add some 911 to the fuel and that didn't seem to help.


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## northmanlogging (Feb 25, 2018)

Change primary and secondary filters, likely the secondary is causing the issue.

Its possible to check lift pump pressure, though I'm not clear as to exactly how. 

If you suspect its a line, run a line straight from the lift pump to a 5 gal can and see how it runs, just remember the return line is going back to the main tank, and will overflow until corrected.

if your filters are all sorts of full of shmoo get some biocide to kill the fungus what grows in diesel, from the sounds of it she sat for some time so either there is a bunch of water in the tank, or water and fungus.

Also Tank should have a drain on it to let any water out.


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## InfiniteJest (Feb 25, 2018)

Sounds like you've done everything I would have, I was just going to suggest the power service 911, you beat me to it. I'm just a dumb faller though.

Looks like it's going to be warmer this week (where I'm at anyways), maybe it'll behave a little bit better.

Almost forgot, I'm really particular about where I get fuel....i stay the hell away from the major chain here in MT. Might save you some future headaches .
Good luck guy.


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## M.R. (Feb 25, 2018)

https://www.bellperformance.com/bell-performs-blog/recognizing-diesel-fuel-algae
.
Yip! Like many been there for sure.
Couple years back had the neighbors
Cat track hoe in the rock pit w/13K+ hours
Cleaned the fuel screen half dozen times / filters
Scrubbed & Wire brushed the fuel ️ tank a
few times .....& likely been easier to of pulled the
tank & cut a opening to of steamed cleaned it
out. Betting the previous owners never kept the
fuel tank topped off at days end to prevent / cut down
on the condensation.


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## InfiniteJest (Mar 2, 2018)

You gain on it at all this week?


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## ChoppyChoppy (Mar 2, 2018)

If he's been running it for 2 months whatever fuel was in it when bought I'd imagine would be long gone?

We don't normally top anything off, fill when it's close to empty, run till it's close to empty. Some of the iron is 40 years old, hasn't given any issues. dunno.


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## northmanlogging (Mar 2, 2018)

ValleyFirewood said:


> If he's been running it for 2 months whatever fuel was in it when bought I'd imagine would be long gone?
> 
> We don't normally top anything off, fill when it's close to empty, run till it's close to empty. Some of the iron is 40 years old, hasn't given any issues. dunno.




The water has a habit of building up, especially if you never change all the filters.

The algea when you get it usually happens in the winter.


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## 2dogs (Mar 3, 2018)

I would dip the tank with a rag tied to a stick and scrape the bottom of the tank. Use a white rag and look for deposits at the bottom of the tank. If there is residue you will have to clean out the tank or the problem will never go away. Sterilize the fuel tank each fall with a full tank then run it nearly dry. Change the filters often. Use 911 a couple times during the winter.


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## CanopyGorilla (Mar 3, 2018)

Ended up being the lift pump. The secondary fuel filter did have some nasty frozen crap in it too though. I will clean the tank soon. We have a small leak we need to fox anyhow and will just clean it when we do that. My biz partner replaced the lift pump the other day and said it ran like a champ. I'm glad because if that didn't work our next step was replacing injection pump$$$$$$


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## northmanlogging (Mar 3, 2018)

On that leak... unless its a hose or fitting just use jb weld the commercial tank repair stuff all crap all the time


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## 2dogs (Mar 5, 2018)

That's good news OP. I like the idea of an easily replaceable prefilter to get rid of 90% of the tank gunk. In fact my body needs a prefilter to get rid of 90% of the crud I eat. The filter would clog up fast if it filtered out Mexican food.


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## CanopyGorilla (Mar 9, 2018)

northmanlogging said:


> On that leak... unless its a hose or fitting just use jb weld the commercial tank repair stuff all crap all the time


It's kinda bigger than that. The tank is shaped like a saddle and goes over the drive line to the rear end. We blew the U joint and it shot the drive line into the tank. We "field fixed" it, but it needs a proper repair when we finish this unit.


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## CanopyGorilla (Mar 9, 2018)

With the lift pump replaced it is running great though. Been going up stuff in second gear it was powering out of in first before.


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## CanopyGorilla (Mar 9, 2018)

a wee bit stuck the other day


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## InfiniteJest (Mar 9, 2018)

You wouldn't happen to be into ice climbing ? Guy I cut for was telling me a real similar story about his climbing partner this past week.


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## ChoppyChoppy (Mar 10, 2018)

Whoops!

The section we are logging now, there's been some pulls that I just about had to get into a spot ike that to get the logs. Dual arch is sure nice to help move the skidder around when it's stuck.


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## CanopyGorilla (Mar 10, 2018)

InfiniteJest said:


> You wouldn't happen to be into ice climbing ? Guy I cut for was telling me a real similar story about his climbing partner this past week.


He was probably talking about my business partner. Do you cut for Smith?


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## InfiniteJest (Mar 10, 2018)

CanopyGorilla said:


> He was probably talking about my business partner. Do you cut for Smith?



I do, small world!


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## InfiniteJest (Mar 10, 2018)

Sounds like you guys have had a tough go of it, hope the snow goes away quick for you.


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## ChoppyChoppy (Mar 10, 2018)

InfiniteJest said:


> Sounds like you guys have had a tough go of it, hope the snow goes away quick for you.



The snow to STAY for another 3-4 months would be really nice.
Snow melting means mud and being shut down for ~2 months.


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## hayboy (Mar 31, 2018)

Fungus about fingernail deep.


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