John Deere 2840 Injectors

[Anonymous-0]

I have a 79 JD 2840 I just rebuilt the engine in. (New pistons,sleeves,main bearings,valves and injectors.) The injector number is an AR89564 and apparantly it goes in about ten thousand different applications sooooo, what I was wondering was if anyone out there knew what adjustments should be made to them before startup. The old ones were adjusted so that the lower locknut adjustment(spray pressure??) was screwed pretty far out, and the upper locknut and set screw adjustment (relief pressure??) was screwed about 90% in. The new, out of the package ones are just the opposite----adjust the same as the old ones, or run with it??? Thanks for your input and advice!!

 

[John Heine]

I always tested new injectors cracking pressure very seldom do you find a bad one.If you have bad one take it back to seller.You need nozzle tester.If I did not have one to test new injectors I probably just use them.I would not go by how far locknut and adjustment were set.

 

[JDemaris]

You shouldn't be adjusting the old ones or the new ones. New injectors are designed to settle a bit after being run awhile, so pressure will drop a little on its own.

The best way to do it is to change all injectors at once with new. But, at $45 each, I can understand some hesitance.

Also, new injectors tend to be set at a higher pressure anway, as compared to the originals. And, if you try to turn up an older used injector to match a new one, it will usually result in an injector that works lousy.

In regard to your comments about spray pressure versus relief pressure - you kind of lost me. They are exactly the same thing. When an injector cracks open, it sprays. One valve, one opening, one pressure. The two adjusters are - #1 for lift travel length/stroke, and #2 - for opening pressure.

 

[msb]

There have been a lot of changes made to those injectors since they came out. I would use then straight out of the box. A lot of them have been destroyed by using nozzle tester fittings that should have been thrown away years ago.Yes, even new nozzles.

 

[msb]

Now don't let any idiots get under your skin the next time.O.K. But considering it was your grandson, I can relate.

 

[Bushed]

I recently replaced all four of my injectors with new, when one developed a miss-fire.

I didn't touch them at all, and it again runs like a deere.
Aussie

 

[Anonymous-0]

It's good to see our resident diesel experts(msb and Jdemaris) back together on the same thread.

 

[Anonymous-0]

I heeded your advice and left the injectors alone. Primed and bled out the fuel system at the filter, and at the two injector pump bleed screws. Good flow, no air bubbles. Cranked and cranked on the engine-no start. Cracked all the hardlines at the injectors, good rhythmic flow to all six, still no start. Pulled the return line at the fuel tank and it seems a large amount of fuel is returning to the tank. Get a little white smoke when cranking, no pop though. Any thoughts?? Adjust the injector pump timing a couple degrees?? HELP!!!!

 

[JDemaris]

Nope, not my grandson, the little guy is my son. I now have four grandchildren and one son that are all around the same age, and my oldest kid is 38 years old. All I can say is, stuff happens - including "surprise" children when you think you're all done.

 

[Mike Aylward]

John, I have had new ones be bad, too. Not that many, but it does happen. Usually the ones that are bad are just "squirters" and do not crack. To me it is just like testing a thermostat before you install it. It likely is ok, but not 100% are. Mike

 

[MSM]

Did a machine shop redo the head? If you just put new valves in,and ground the seats, there is a good posibility the stand out is not correct,which effectively lowers the compression ratio.This causes hard starting and poor fuel economy.I just had a head done on a "rebuilt" 2940 that wouldn't start on an 80 degree day unless you ethered it. It took another set of valves,new seats and a flat surface to get it in spec.

 

[Nancy Howell]

Hooray! You"re back. So very pleased!

 

[buickanddeere]

jdemaris. Good to see you.

 

[msb]

Lat comers come to those who are VERY bless, John and you, my friend are a treasure. I also was blessed with a latecomer. She is now a 36 year old momma herself.

 

[DONMYEIL]

If the injectors were set to the correct pressure and tractor wont start it could be the pump is worn enough it no longer can crack the nozzles. It happens.
Also crank speed can be a large factor as well.

 

[griz50]

Hi everyone, I'm glad to see John back too, I just found this site a few days ago and didn't know you were gone. But I have been reading many of your posts about Rooso Master pumps on 40 series JD tractors, I'm about to repair one myself or try too as soon as the manuals arrive. Will be checking back.