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Happy New 955L Owner With Questions

thepumpguysc

Senior Member
Joined
Mar 18, 2010
Messages
7,445
Location
Sunny South Carolina
Occupation
Master Inj.Pump rebuilder
The air in the cracked fuel lines tell the story..
Your sucking air.. which could mean a clogged tank outlet..
The reason it runs for a short time is, the supply pump is sucking the fuel from the filters..& by the time u get there to check it, gravity has filled them back up.??
Check every connection from the tank to the IP.. one might be sealed with a rubber grommet.. the grommets get torn but won’t leak fuel BUT WILL suck air..
I would start at the filter INLET.. take off the line and put in a 5 gallon bucket.. fuel should flow freely..
Let it run for a minute or two.. any blurps and u got floaters in the tank.
If ok, hook it back up and go to the other side of the filter..
Remove the line and check the flow..
 

leadfarmer

Well-Known Member
Joined
Dec 17, 2019
Messages
229
Location
SW PA

If I get an alternative fuel supply rigged up I can at least crack the injector lines on top of the pump and see if that eliminated the air bubbles to confirm the suction leak, right?

I think every connection is a brass compression fitting, except for the barb fitting rubber hose ends.

I've been pounding fence posts lately. Still haven't had a chance to do anything else, but I hope you're right and my injectors and pump are not the problem.
 

workshoprat92

Senior Member
Joined
Dec 15, 2014
Messages
817
Location
Bois D Arc Missouri
This thread is timley for me. I am having the same issue with a 955l. Ran fine when parked. Two weeks later went to start it and it runs for a short amount of time and stalls. Have to let it set a bit and it will fire back up but stalls again. Changed fuel filter and water seperator. No change. Getiing good fuel pressure on the gauge. When running you can crack the injector lines at the pump. 1,3 and 4 all have a change in tone and cause a misfire. They spurt a small amount of fuel but nothing extreme. Crack open number 2 and there is no change in tone or rpm. It flows bunches fuel! Not a spurt like a timmed injection but a massive constant flow like an open fuel hose! When it runs it runs like its at high or full throttle and wont idle down till it sliws down and dies out. Any ideas? Sorry hate to hijack this thread but our problems seem so identical.
 

Bluox

Senior Member
Joined
Jun 19, 2010
Messages
1,960
Location
WA state
This thread is timley for me. I am having the same issue with a 955l. Ran fine when parked. Two weeks later went to start it and it runs for a short amount of time and stalls. Have to let it set a bit and it will fire back up but stalls again. Changed fuel filter and water seperator. No change. Getiing good fuel pressure on the gauge. When running you can crack the injector lines at the pump. 1,3 and 4 all have a change in tone and cause a misfire. They spurt a small amount of fuel but nothing extreme. Crack open number 2 and there is no change in tone or rpm. It flows bunches fuel! Not a spurt like a timmed injection but a massive constant flow like an open fuel hose! When it runs it runs like its at high or full throttle and wont idle down till it sliws down and dies out. Any ideas? Sorry hate to hijack this thread but our problems seem so identical.
Your problem is different .
Which pump do you have?
Bad Bob
 

leadfarmer

Well-Known Member
Joined
Dec 17, 2019
Messages
229
Location
SW PA
It must be cat fueling problem season.

A guy with a D3 or D4 on the facebook group seems to have similar issues.

It's too bad I can't see the outlet of my fuel tank from the filler hole. There's baffles in the way. I think I will drain it and borrow a friend's borescope to see what it looks like.
 

leadfarmer

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Joined
Dec 17, 2019
Messages
229
Location
SW PA
Back to it.

Drained the tank last night. Attached picture shows the crud that came out of the drain, which is separate and next to the fuel outlet.

I filtered all the fuel through a funnel with a screen as it drained. No major findings.

Tonight I go in with a borescope.

I removed the fuel filter assembly, completely disassembled it, cleaned everything, and put a new Cat made primer pump on it. I didn't realize ALL the fuel flows through the primer pump. So a leak in the primer pump seals would be bad.

On the outlet side of the filter housing, the fitting has an o-ring that I didn't know about. Same goes for the fitting at the inlet of the governor housing. I'm picking up new o-rings as they look tired.

No inline screens found in any connections or fittings.

I replaced a section of the 5/16" brake line that goes from the governor to the air intake, it appeared to have a tiny pin hole in it where it was rubbing and wearing.

I removed the fuel hose that goes from the hard line from the tank to the filter housing. It is some heavy duty air brake hose. I don't think this was causing a problem. The inside of the hose looks good, and it is stiff as hell. It's getting replaced with proper 3/8" fuel hose though.

Got to fill the that hard line with alcohol and blow it through the line tonight to clean it out.

I also picked up a new drain petcock from Cat for the fuel injection pump. The old one probably needs new stem packing.

Hopefully one of these things I'm doing fixes the issue. Can't say I have the time to properly do one at a time. I've been swamped for the past month with the day job and putting up horse fence, finally got some time to work on this.

Saturday I'm going to look at a Caterpillar R5 that is mine for free if I want it. It's been sitting 4 years in a pole barn. Needs some work, but is supposed to run and operate as it is. Has a hydraulic blade on it. Still has the original gasoline engine in it. Not the ideal dozer, but free is for me.
 

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leadfarmer

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Joined
Dec 17, 2019
Messages
229
Location
SW PA
Well things have been frustrating yesterday and today.

temps in the low 60s both days.

yesterday I tried to start it. Added fuel, primed pump. Cranked and cranked, puffs of white smokes, no start. I found one fuel hard line connection at the tank leaking and tightened the fitting. Toasted a battery terminal. Time to clean those I guess.

This morning I cleaned the battery terminals and replaced the one that melted.

Realized I should probably bleed the injectors.

Did that once. No starting. Got it to run on either but it wouldnt keep running.

bled the injector lines again. At the pump and at the injectors. Got fuel.

still no starting.

rigged up a can of fuel directly to the primary filter inlet. Primed pump and bled injectors again. Still cranking with white smoke. Popped once now and again but its just not starting. Got fed up and had to walk away.

i need to look at the air filter and make sure chipmunks didnt move in.

other than that, I am scratching my head pretty hard!

I drove it right to where i parked it, drained the fuel from the tank, cleaned the lines and filter housing, put it back together. When i had my fuel issues before at least it would start and run. Grrrrrrrr!
 

DMiller

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Feb 21, 2010
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Hermann, Missouri
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Cheap "old" Geezer
You are not getting enough fuel
White smoke is fuel unburned so is getting some, starts on ether but dies says fuel.

Time to pull and inspect check valves for trash moved to them.
 

leadfarmer

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Joined
Dec 17, 2019
Messages
229
Location
SW PA
Check valves? Like a pressure relief valve in the injection pump?

well I had a win today but not on the 955L.

got a 1937 R5 to fire up. Just had to clean the contacts and rig up a fuel can. Bringing it home soon.
 

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Welder Dave

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Oct 11, 2014
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Canada
They're about the size of a watch battery. I changed mine but didn't need to. That was before I discovered the screen in the fuel line. I can't remember where they are it was so long ago.
 

leadfarmer

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Dec 17, 2019
Messages
229
Location
SW PA
Alright alright, focus everyone! lol. I will make a separate thread on the R5.

Back to this 955L issues.

So to summarize:

I feel confident at this time that clean, air free fuel is being supplied to the IP, so what could be the culprit keeping me from starting? And what was possibly the cause of my air in the injector lines and low power issues before?

Possibilities:

1. Injectors/capsules

2. Check valves in the pump

3. Lift pump in the IP

Those are the three possible suspects brought up when I went back through the last few pages of this thread.

What I know so far:

1. This looks like it will cost me $400 and a few hours.

2. No clue how to attack this one.

3. No clue how to attack this one.

Some suggestions for further troubleshooting:

- Electric fuel pump to push fuel into the IP and rule out the lift pump
- A test of shutting off the fuel and squirting oil into the injector to see if it shoots it out, not sure how this would work?

So at this point I can feel the frugality leaving my body and I am setting the fuse on the parts cannon lol. I'm running out of weather and I have a few things I really need to get done.
 

Welder Dave

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Oct 11, 2014
Messages
12,257
Location
Canada
I can't remember but is it turning over really fast? Just thinking maybe a starter issue. Does it have a block heater, if so plug it in and get the engine really warm. The check valves are simple enough to check. Is there a way to put 3 or 4 psi to the fuel tank to help push the fuel. It seems like your machine is on the verge of starting. I'm thinking once it starts it might be much easier the next times if it's air locked or something.
 

leadfarmer

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Joined
Dec 17, 2019
Messages
229
Location
SW PA
So, I was also thinking along those lines. Get a block heater, verify all 4 glow plugs are working. I think they are, the ammeter needle moves when I switch to preheat. I can just check all 4 for equal resistance to see if one is sleeping on the job. I need to check in the operator manual how long to hold them on. I usually go 15 seconds but Ive heard people say to use them for a minute.
 

AllDodge

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Apr 2, 2011
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2,288
Location
Kentucky
I use glow plugs for at least a minute always except hot summer time. When it starts getting cooler I do it longer. Read somewhere it can be as much as 15 minutes wen pretty cold. Mines old and it does start easier when I use them

My 20amp resetable breaker/fuse pops after about a minute so I let off, give it a few seconds and back on longer. Do need to get around to replacing it, its blowing to easy. All my glows are fairly new
 
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