TL80a Engine popping - help!!!!

Sawdustsmb · Mar 20, 2012

On 6/9/2011 a member "Tazewell" posted a "Engine problem" with his TL80a popping. I seem to have the same problem. Of course he didn't tell if it was ever solved and doesn't respond to private messages. I posted a few months ago and it was moved by admin - then Hyjacked. So here is my last attempt. When under light load - baling etc at pto speed - 2200 rpm- it will make a popping noise in the exhaust. If I turn slightly down hill it stops. The tank has been removed and drained, All filters replaced. It is a 2005 with 700 hrs. Injectors were taken out and tested. It has been to the NH dealer - nothing found. Last suggestion from them was to add a small bottle of chainsaw oil in the fuel. And it has had all kinds of additives in the fuel. When bushhogging with a 7' hog last fall it would start as soon as you turned uphill - usually - last for part or all of the uphill run. I will try to upload a video in which I was spreading lime. You will hear it stop as soon as I turn downhill. Getting up on this field it would lug down to 1500 rpms and up to 2500 AND you guessed it - no popping. I wonder about valves -NH thinks not. Any help would be greatly appreciated before something in this engine goes bad. Thank you. Bob PS. sorry - guess my video isn't in the proper format. Maybe tomorrow.

DieselMonk · Mar 20, 2012

Interesting indeed! So what exactly have you tried doing so far to fix it? I see you mentioned a few things, but then it doesn't say what the dealer did or didn't do.

I find it is interesting that the problem only occours with a light load going a slight uphill. When this happens, does the engine loose power? What happens if you give it full throttle.

If it is a valve problem, it would be there all the time IMO. Anyway, I'd be doing a compression test, that would answer that. Thinking about it some more... could it maybe a valve spring problem? Kinda make the valves "float", not closig properly under certain circumstances? A bent push rod comes also into my mind. Could be also a "timing" issue.
On Common Rail diesels could be rail drain... Anyway... that's all I can come up with for now.

Jerry/MT · Mar 21, 2012

Sawdustsmb said:
On 6/9/2011 a member "Tazewell" posted a "Engine problem" with his TL80a popping. I seem to have the same problem. Of course he didn't tell if it was ever solved and doesn't respond to private messages. I posted a few months ago and it was moved by admin - then Hyjacked. So here is my last attempt. When under light load - baling etc at pto speed - 2200 rpm- it will make a popping noise in the exhaust. If I turn slightly down hill it stops. The tank has been removed and drained, All filters replaced. It is a 2005 with 700 hrs. Injectors were taken out and tested. It has been to the NH dealer - nothing found. Last suggestion from them was to add a small bottle of chainsaw oil in the fuel. And it has had all kinds of additives in the fuel. When bushhogging with a 7' hog last fall it would start as soon as you turned uphill - usually - last for part or all of the uphill run. I will try to upload a video in which I was spreading lime. You will hear it stop as soon as I turn downhill. Getting up on this field it would lug down to 1500 rpms and up to 2500 AND you guessed it - no popping. I wonder about valves -NH thinks not. Any help would be greatly appreciated before something in this engine goes bad. Thank you. Bob PS. sorry - guess my video isn't in the proper format. Maybe tomorrow.

The TL80A is a NA engine isn't it? No Turbo?

How long has this been going on? I wonder if you're sucking air in the fuel line while at high power/ high fuel flow rate. Make sure all the fittings are tight. Go over the fuel lines from the tank to the pump to the injectors.

Is your airfilter clean? A restricted air filter will cause you to lose power and run hotter. I don't know why that would cause a popping noise in the exhaust but it's an often overlooked maintenance item.

Oldtractorfixer · Mar 21, 2012

Just a thought, I wonder if there might be water or something in the bottom of the fuel tank that goes over intake on uphill but goes away on downhill. I doubt it's valves or anything like that as uphill/downhill wouldn't make any difference. I suppose it could be a thrust washer on the cam or in the injector pump that would let a shaft move back and forth, but I think that would be a long shot.

pjbci · Mar 21, 2012

It has a bad injector. Ive had several injectors that blew. Each time it caused a poping noise under a load. One tractor even blew smoke rings every time it fired. Just crack each injector line one at a time with the enjine running. You will find the bad injector when you crack a line and the engine doesnt change tones as much as cracking the rest of em does.

RickB · Mar 21, 2012

Low fuel supply pressure to the injection pump or faulty injection pump. Very, very common problem with Bosch rotary pumps of that age. Expensive fix if your 5 year EPA emissions warranty has expired.

Sawdustsmb · Mar 21, 2012

Thank you for all your responses.
Diesel Monk - Dealership checked the supply to the pump and switch at the pump. Put air pressure to the return line which seemed to be partially blocked then let go. (could the return line be to small??) Interesting valve float idea - would they float under heavy load when revved to 2500?

Jerry - NA engine - bought tractor w/600 hrs. 1 year ago. Started noticing problem when mowing and baling last summer. New air filter (was really pluged up when it came from dealer - different by the way from the one working on it), water filter, fuel filter.

OLD Tractor - I removed the tank, drained it, made sure all hoses were free

PJBC - Injectors were tested with a hand operated tool at the dealership - OK or could one still be bad???

RickB that's not nice!!!! The way things work here - you are probably right - the most expensive fix would fit right in. Better though than a new engine.

In general: I will never ever buy a piece of equipment when the seller says "it is field ready" or a dealer says " the previous owner never did anything to hurt it". and what's with auctioneers saying " such and such tractor has 265hrs "it's new" DA!

Thanks again for your help - If I can't do the work maybe I can suggest some ideas for the NH mechanics.

Bob

pjbci · Mar 21, 2012

Injectors ok then. One more thing I would chk for before pulling injector pump off. Look very closely for an exhaust leak around the exhaust manifold.

Sawdustsmb · Mar 21, 2012

http://videos.tractorbynet.com/video/1070/Popping-tractorA couple of things I forgot to mention - sort of -

When I was bush hogging it didn't bother for the first half hour or so then not always when turning up hill. It might last for the whole uphill run or 100 yds. or not at all. The rpm's will drop about 200rpm's and stay there - I think I remember trying to rev it and it just makes the condition worst. If I wear ear plugs you can just watch the tach and know.

I wish I could upload the video so you could hear it. Maybe my son can help me tonight.

I going to go search for an exhaust leak.

Bob

Jerry/MT · Mar 21, 2012

Sawdustsmb said:
Thank you for all your responses.
Diesel Monk - Dealership checked the supply to the pump and switch at the pump. Put air pressure to the return line which seemed to be partially blocked then let go. (could the return line be to small??) Interesting valve float idea - would they float under heavy load when revved to 2500?

Jerry - NA engine - bought tractor w/600 hrs. 1 year ago. Started noticing problem when mowing and baling last summer. New air filter (was really pluged up when it came from dealer - different by the way from the one working on it), water filter, fuel filter.

OLD Tractor - I removed the tank, drained it, made sure all hoses were free

PJBC - Injectors were tested with a hand operated tool at the dealership - OK or could one still be bad???

RickB that's not nice!!!! The way things work here - you are probably right - the most expensive fix would fit right in. Better though than a new engine.

In general: I will never ever buy a piece of equipment when the seller says "it is field ready" or a dealer says " the previous owner never did anything to hurt it". and what's with auctioneers saying " such and such tractor has 265hrs "it's new" DA!

Thanks again for your help - If I can't do the work maybe I can suggest some ideas for the NH mechanics.

Bob

Just to follow up on RickB's comment on low delivery pressure to the injection pump. Does your engine have a lift pump in the fuel delivery circuit and if it does have you cleaned its filter? There is a screen under the top cover of the lift pump on my TD95D.