John deere 455 Questions

[dconrad246]

Have a John deere 455 i am trying to get tuned up. The engine rpms are about 300 to 400 low and am trying to fix it. Already adjusted the governor and the valve lash but no change. what else do i need to look into? I have an issue with starting right now in that it starts hard but runs fine and starts fine once its warmed up, replaced the glow plugs and that made it better but didn't fully fix it. just wondering what i am missing and what else to check. wanted to try and get a service manual but cant find one for less than $300.Thanks in advance for any help.

 

[Kish318420]

Have you looked at the throttle and cable area?

 

[dconrad246]

yes, the cable is maxed out. the bracket was a little bent so bent it back and there is no more travel in the whole thing. I also tightened up the Fuel solenoid mechanism as well because that was a little loose. idle rpms are also low as well, but that i think i can adjust with the bolt on the throttle mechanism to bring that up. more concerned that the high end is low, the rpms on the front pto are 300 short as well and it is affecting the 60 inch deck cut quality. Plus with winter coming i want the power for the broom to work properly.

 

[Kish318420]

What RPM are you shooting for on the diesel?

 

[dconrad246]

i think the manual i found said around 3200. Unless there is something i am missing to up the pto rpm.

 

[dconrad246]

now that i look the specs say 3350 rpm and i am at 2900. rpms on pto are 1800

 

[Kish318420]

I would try running some Seafoam (or your favorite fuel/engine cleaner additive) to clean the injectors, valves and combustion chamber. It should help the injector pump also. It will take a few tank fulls. Have is the fuel filter/air filter?

 

[dconrad246]

Swapped the filters and did full fluid changes when i got it. that was about 40 hours ago. ran some seafoam through it (Probably in a bad way) and it didnt help yet. will try again and see if there is a difference. I ended up shutting off the fuel then filling the fuel filter bowl by the engine about a quarter to half full of seafoam then ran the engine for about a half hour at full throttle. will try again and see if it helps.

 

[Kish318420]

You'll blow your engine that way!! Just put it in the fuel tank and also in the oil. VERY IMPORTANT: FOLLOW DIRECTIONS on the can for diesels!

 

[dconrad246]

So, still no change. (Ran the seafoam correctly this time) then double checked the valve lash and that was correct. Tried adjusting the governer again and noticed it was basically maxed but I am not getting black smoke like I believe I should at this point. What else is there to check? I am thinking fuel pump but don't think it would be running right at all if that was the case. Hoses aren't pinched anywhere that was the next thing I checked. Any other ideas?

 

[Kish318420]

Remember, I said it takes time to work a few tanks at least! It is not instantaneous! Do you have the mower on it? Do a load test with it on the tractor and the mower engaged. If it stalls/dies then I would look at fuel pump in tank it may be clogged with gunk or pump not delivering the rated fuel needed. If it delivers the rate of fuel needed then it is the fuel injector pump issue. Then I would take it to a diesel shop for a check out.

 

[dconrad246]

I have the broom on it right now. Using the shaft on that to get the mid pto reading. Whats the best way to check the fuel pump rate? Can check that tonight and see if its easy.

 

[Kish318420]

Something that can measure quantity (measuring cup that can hold 2 or 4 cups, plastic, one that will stay in the garage) and a watch with a second hand, stop watch function on some watches or smart phone. Pull hose off at fuel filter (after/before) (in case fuel filter maybe issue) and place into container, turn key.

 

[BravoXray]

Not familiar with a 455, but does it have an electric fuel pump?
If so, can you hear it clicking when the ignition switch is on?
If you do, put a gauge on the line to the injection pump and check the pressure there.
I you don't have at least 4-5 psi, you have a restriction or plugged filters.

 

[beenthere]

Service tech manual for the 455 shows fuel flow test and pressure test.

 

[dconrad246]

Well flow is good so that's eliminated. got a message to a parts guy to just get a newer set of injectors and a newer pump (he sells used parts) just going to throw some parts at it and see what happens. maxed the governor out so bad that i blew out the top of the acorn nut that covers it when i put it back on but still not getting bogged down or any black smoke like i think i should be at this point, so gotta replace that when i get to a dealer again. Is there a good place to get a tech manual for this thing? everywhere i look the prices are way high. would be nice to just find a download for cheap. Next i gotta find a heater, cab and snowblower for this thing.

 

[dconrad246]

anyone know of an aftermarket fuel pump that i can replace this with. checked used and everyone is out in my area, and the dealer wants 230 bucks for just the pump.

 

[dconrad246]

Well I am at 2950 rpms. that 300 rpms is eluding me. pump seems good, the injectors are going to take a bit to clean, and the governor is maxed. replaced the little 2 inch piece of line on the pump because it was pretty shredded but nothing else seems wrong. there is a little nut screw thing on top of the injector pump 90 degrees off from the governor adjustment that I don't know what it is. if anyone knows what does that do? i feel like I am missing an adjustment SOMEWARE just don't know where. Help has been great so far, any more will be greatly appreciated. The parts guy i was talking to is out of injectors so going to run with what I got for now.

 

[dconrad246]

the gold colored nut on top is what I am wondering about.

 

[Dirtdobber1]

According to the manual you have an early style pump, meaning before EPA regs were applied. That gold nut hides the fast idle screw. Remove the nut and under it should be a lock nut with a screw that is adjustable to accomplish the correct high idle, which is 3350 +/- 100 rpm's.

However, I would be concerned with the cause in the drop of rpm's. You didn't give us any history on the machine. No. of hours? Did you acquire it with this problem or has the problem creeped up over time. Is the air filter clean? Forgive me for asking this, but when you adjusted the valves did you know how to properly do it - engine cold, intake and exhaust clearance .008", no lifting action on cam?

Another thing is bleeding the fuel system. This is likely not the problem as much as you have run the machine but its easy. Air can get trapped between the injection pump and the injector. This can happen when you run out of fuel, change the filter, etc. Because air compresses it doesn't get pushed through the injector. With the engine running, crack the fuel line nut at the injector and bleed it (one at a time). It only takes a moment. Start with a cold engine and be careful of obvious fire hazard!