TL80a Engine popping - help!!!!

Sawdustsmb · Apr 2, 2012

Bet you guys thought I had gone away or maybe another "we'll never know thread". Not so - just got the pressure gauge in there - about 6 psi at idle and 4 - 4 1/2 psi at 2200rpms. No change when it is sputtering. Drops back to zero right after shutdown. Sounds like we're looking at injection pump timing or injection pump - right?

Bob

DieselMonk · Apr 3, 2012

I am glad to see you back.

On what did you do the pressure test on? can't be compression as there are a few zeros missing. My supercharger does 4 times that you stated. Is it the fuel pressure from the lift pump to the injector pump?

Really you have to figure out which one is the offending cylinder.

Still could be not enough compression, or fuel delivery (injector and injector pump).

All we know now is that the injector pump is getting plenty fuel.

Jerry/MT · Apr 3, 2012

Sawdustsmb said:
Bet you guys thought I had gone away or maybe another "we'll never know thread". Not so - just got the pressure gauge in there - about 6 psi at idle and 4 - 4 1/2 psi at 2200rpms. No change when it is sputtering. Drops back to zero right after shutdown. Sounds like we're looking at injection pump timing or injection pump - right?

Bob

Are those pressures measured under load or at high and low idle? If they're under load, then I'd think there was something wrong with the injector pump. I'd defer to RickB's opinion as he has more experience with this than I do.

Sawdustsmb · Apr 3, 2012

The fuel pressure gauge is after the lift pump between the water filter and 6 inches in front of the injection pump. I guess I would say those readings - 6psi no load at idle. 4.5psi at light load (driving uphill) 2200 rpm. Question - the pressure seems to hold at 6 psi for a couple of minutes at times when shut down. Other times it drops immediately. Could this indicate a leaking (bad) injector leaking down?

barbqranch · Apr 4, 2012

The fuel pressure could also leak down back through your lift pump. That would have been my guess w/o any real knowledge of what is happening.

DieselMonk · Apr 4, 2012

I am not concerned about that loss of pressure once the engine is shut down. All I know thus far is that the injector pump gets enough fuel and the lift pump is not kicking out. So we would have to move on to the injector pump / injectors next.

Funny thing on this story is that the engine is skipping at high rpms. As far as I understand it, it doesn't do that at low rpm's.

RickB · Apr 4, 2012

See posts #6 and #30 in this thread.

Sawdustsmb · Apr 4, 2012

Just a reminder as it's been awhile. The tractor runs great from idle up about 2000 rpm. Does not "pop" when not working as in fast idle. Does not pop when really working hard as when pulling 6 tons of lime up hill and lugging down to 1500 rpm and up to 2500 rpm and down again. POPS when running along at 2200 rpm and light load like baling or running a 489 haybine. Drove it down the road the other day, down hill fine, starting uphill poping, working harder on the hill - fine.

Bob

Sawdustsmb · Apr 15, 2012

Hi. Just thought I'd let y'all know, the thing sounds just like a popcorn popper just getting done now. I found out how to get it to stop - put on the brakes!!! If I can figure out how to lock them on without using the one on the pinion shaft I'll be all set. Oh -take the brakes off and poppity pop comes back. Has nothing to do with up and down hill - just in a medium load range. Talked to Messick's they are thinking on it - I hope. Told absolutely not to touch the injection pump - they do not even look at tractors when they see that bolt messed with. Six weeks to start haying - anybody know where one could find a good RELIABLE tractor? I'm beginning to think things started going down hill in the tractor business about 1980.

Bob

DieselMonk · Apr 15, 2012

can you explain that with the brakes again? I think you don't want to drag your brakes so what am I missing? Look on your users manual if there is some brake switch that interferes? I don't quite understand why it quits popping.
A: Is it because you are changeing the load by dragging the breaks
or
B: Just apply enough brake for the brakeswitch to close.
other than that I have NO idea why it would quit popping if you are using the brakes.
Maybe you can explain that a bit better.