# New Holland TL80 losing power



## Sleepymonkey (Apr 7, 2015)

hey folks, been having a few issues with losing power in a TL80 so I blew the fuel lines out, changed the filters, checked the banjo bolts, changed the fuel out. So, I took the injectors out, cleaned them up (I have removed them numerous times to trouble shoot other issues in the past) and went to put them back in and had a lot of trouble getting one of the banjo bolts hooking up the fuel return line. The bolt was semi stripped and it would not go in the injector and it turns out a good bolt from another injector wouldn't go in the injector either. So I turned the bolt and turned the inside of the injector and the bolt finally would go in, so I hooked up everything. I primed the system, turned it over and it started and idled for 60 seconds then died. I cracked the heads and noticed the second head had air in it....the same injector with the stubborn bolt. I primed it, started it again and noticed a little air coming out of the banjo bolt in the injector. When it died, I could also see some fuel coming out. The bolt seemed to go in fine after I cleaned it up and it snugs down into the injector however, air and fuel are getting out. Is air penetration at this point causing the problem, or would this be caused by air getting in somewhere else and this is the point where it is being pushed out? Sorry if this is a stupid question - just learning about diesel engines. THANKS
JM


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## harry16 (Dec 8, 2011)

The return line is a low pressure line back to the fuel tank. Yet you have a leak in a return line connection? The banjo bolt could be bottoming out before making a tight connection? You might consider replacing the injector. I'm wondering if you have a blockage in the return line, causing it to pressure up? 

Since you are seeing air in the return fuel, and the engine quit running, you still have air in the system. 

Does your TL80 have a lift pump in the system before the filter? Maybe a connection leak is introducing air into the system at the lift pump.


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## Fedup (Feb 25, 2014)

You mention checking banjo bolts. Checking for what? If the fuel system has been undisturbed until the problem developed, the only fitting in question would be the one at the primer pump inlet. I have, on many occasions found the passage within the bolt and/or the hose barb itself partially plugged with debris from the tank. Also, have you removed the cover from the primer pump and checked/cleaned the screen? Has there possibly been any history of losing the fuel cap and running without one for a few days while a replacement was on order? About blowing out the lines. What lines exactly were blown out? Here again, the only one I would be concerned with is the supply line from the tank to the primer pump, and not much else. 
As for return line leaks, that won't introduce air into anything that affects performance. It's just a leak, nothing more. Unless you somehow scratched or damaged the actual seal surfaces of either the injector body or the bolt head, the leak is most likely just a deformed copper washer and should be an easy fix.


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## Sleepymonkey (Apr 7, 2015)

the two banjo bolts I check are the supply into the primer pump and and the supply into the first filter. I blow the supply line from pump back into the tank and the line to the filter. The surface of the injector where the copper washer goes has a small gouge in it. I noticed this morning that after the engine died, I cracked the head to the injector in question and it seemed to be under pressure and when I broke the seal, I could see fuel mixed with air come out. Shouldn't the air we going thru the bolt to the return line? so if air is getting in thru the bolt/injector connection, would this cause the engine to stop.


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## Fedup (Feb 25, 2014)

Just for the record, this is a TL 80 right, and not a TL80A? 
If you're getting air into the system, it's coming in before the injection pump, not through the return lines. Pressure buildup in the return system can cause the engine to lose power, drag down and eventually die. That, yes, but it won't put/let air into the system. with a blocked return the engine will start right back up once the pressure in the return line subsides. When air enters the supply side and the engine dies as a result, you will have to bleed something again before it will start back. Which scenario fits your situation??


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## Sleepymonkey (Apr 7, 2015)

Yes sir, it's a tl80. So today I blew out the return lines from the injector pump and from the injectors into the tank, so they should be fine. I fired it up and it ran for 10 seconds and died. I waited 5 minutes and repeated and it started and I got the same result. I did it again. So I pumped the fuel pump at the primer a couple times and noticed two things, a hissing sound at one of the banjo bolt connections on an injector and bubbles coming out of the screw on the fuel filter. I tightened it....and it wouldn't tighten down tight, snug, but it still turns. Stripped on the female threads I guess. Would this be the culprit?


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## Fedup (Feb 25, 2014)

If you have fuel and air escaping from the bleed screw on the filter base, you need to replace the filter base. The supply pump forces fuel to and through the filter, yes, but the injection pump has an internal transfer pump which is quite capable of drawing fuel(and air) into it. Replace the base, eliminate that particular issue, then see what happens next. As for the return line banjo fitting, I will try this one more time: a leak on this side of the system will not affect engine performance. It will only create a mess.


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## harry16 (Dec 8, 2011)

Quote: "I pumped the fuel pump at the primer a couple times and noticed two things, a hissing sound at one of the banjo bolt connections on an injector and bubbles coming out of the screw on the fuel filter. I tightened it....and it wouldn't tighten down tight, snug, but it still turns. Stripped on the female threads I guess. Would this be the culprit?"

The filter leak (bubbles coming out of the screw on the filter) is probably the source of the air leak that prevents your engine from running. Is this the bleeder screw for the filter? If so, you use this screw to bleed air out of the filter during the purging process.

The banjo bolt leak at the injector is a return line leak. This is a low pressure leak. Maybe the damaged threads in the injector are preventing the banjo bolt from tightening all the way down?


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## Sleepymonkey (Apr 7, 2015)

thanks guys - I will order a base today.


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## Sleepymonkey (Apr 7, 2015)

ok so I replaced the filter base and the filter, primed the system and turned it over. The engine turned over for 1 minute then died. I waited 5 minutes and repeated and go the same result. I noticed that fuel (mixed with bubbles) in the return line from the injector pump was traveling back into the injector pump, and that the return line off the injectors had no fuel in it. I cleaned off the supply lines and cranked it - then noticed as it was running small bubbles coming up from the tank. I tightened down the supply fittings into the tank and it still did it. I am presuming that the brass fitting/suction pipe connection has been compromised.


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## Fedup (Feb 25, 2014)

It seems to me you still have air getting into the fuel supply. Possibly an issue with the tank/outlet/supply hose? What I would do -- remove the supply hose from the primer pump inlet banjo fitting. Using a jug of clean fuel and a section of 5/16 fuel hose, create a supply of fuel to the pump totally separate from the tractor fuel tank/supply. Leave the return lines as they are and run the tractor from this new supply and see what happens. If it still does the same thing, then your problem is related to the supply pump, injection pump, or the fittings/hoses between. On the other hand, if it runs as advertised, your problem is with the supply from the tank and its hose(s). 
One more thing that hasn't been mentioned. Does your tractor by chance have the optional water separator/filter under the right side cab/floor plate? These are often ignored/neglected as many people don't realize what they are or sometimes forget they are under there. This is another good possibility for the symptoms you describe.


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## sixbales (May 18, 2011)

Attached are parts diagrams for a TL80:
1) Fuel tank piping
2) Fuel filter
3) Variation fuel filter
4) Fuel lines


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## Fedup (Feb 25, 2014)

It would look something like this.

http://partstore.agriculture.newhol...ementNL/parts-search.html#epc::mr61442ar25085


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## Sleepymonkey (Apr 7, 2015)

I have said this before and I will say it may times to come. Man, do I feel stupid. The issue is between the suction pipe and the 90 degree elbow that connects to the fuel line. 

Note to self: when you suspect an under/over fueling problem - put a light behind the fuel lines and look for air FIRST....not last.

Thanks for your help. Not sure where the air is getting in. I have taken apart and cleaned the 90 degree elbow and reattached but getting same result so I am just going to replace all three parts.


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