802 dies, no overload fault

[Jeepadict]

After an unmotivating winter, I'm making another attempt at this project 802 I have. There was a noteworthy list of problems when I got it, and I'm starting to see the light at the end of the tunnel.

It's a smooth running machine, up until I attempt to go over 74 PRC on the AC Ammeter, then it pulls the engine down below power indicating levels and sometimes will even stall the engine...but never once has it shown any fault lights other than oil pressure AFTER the engine completely stops. Most times reducing the load won't correct the behavior back to normal, I have to remove the load completely before it dies and start again. On occasion when trying to load it the RPMs drop very low but doesn't die, just grumbles along until I open the contact. I'm using a combination of 3 electric space heaters (two ceramic 1000W 110V on opposite legs of the box, one coil wire 5000W 220V) as an improvised load bank (via 50A spider box) to give me flexibility in the load that I apply to the machine. With the engine at full temp, the best truly balanced load I can attain without it dying is 108.2 VAC 18.8A per hot leg using an amp clamp and meter...my math comes to 4068W total. I can get it to pull a slight bit more on one leg (or the other) before it dies, but only 353W worth. When I apply the larger loads I can see the HZ meter drop a bit as I'm used to with my other machine, but where my other 802 will recover and I make slight adjustment to the Frequency Adjust Control this machine just keeps dropping until the HZ meter zeros. Even attempting to max the FAC just before I add a higher load, the machine still bogs down below a functionable level. With all things taken into account, my gut tells me this is most likely a fuel starvation problem...leading me to believe that the Governor requires adjustment or repair.

Disqualifying factors: I've already done a good bit of work to this machine...fixed oil drain line leak, misc wire harness repairs, replaced multiple leaking fuel lines, replaced oil press sending unit, upgraded both well nuts, replaced fuel/oil/air filters and water separator, repaired battery cables, installed new starting batteries, installed missing fuel fill cap, installed many missing case fasteners. All fault lights test good. Remaining discrepancies beyond this low power problem: Oil Press gauge inop, Voltage Adj rheostat bad, and coolant flush. The only thing I have not ruled out yet is the fuel quality, but the fuel is fresh from upgrading the well nuts and I can get the machine to duplicate the failure multiple times over.

In my efforts to scour the TM for the Governor adjustment, the closest task I can find is "4-7 ADJUSTING FREQUENCY DROOP AT ENGINE GOVERNOR". As I'm a big grey airplane guy, and not a ground equipment guy...this is where I find my cause for pause and defer to the judgement of those more experienced than me, because even with the help of the internet I'm having difficulty understanding FQ Droop or the table that depicts the adjustment parameters. I'm all about tinkering, but playing "Parts Darts" is far from my favorite game. Is anyone familiar with this machine's described behavior? When I find the troubleshooting in the TM for a low power condition it flows down a engine failure line of head and valvetrain damage...but that doesn't feel right in this instance.

Thanks in advance! ST

 

[Light in the Dark]

I wouldn't adjust the governor just yet. I suggest you put a full can of seafoam in the fuel tank, and run it at 70-75% rated current figure you call out (before the issues start happening) for as long as your fuel allows (or make sure the tank is at least half full) and run it till its almost empty. Give the internals a good cleanout (and 70%+ it will be running efficiently, without any concern for wet stacking). You may find this alleviates the problem... you may not. If you have injectors that are starting to clog, or metering pumps which need to be cleaned, or upper cylinder buildup issues... the seafoam should start to do its work in helping fix this.

Do you have any sign of wet stacking? How many hours on the set? If the fuel pump the cube Facet or the round Airtex? Does the pump have an inline particle filter on the input feed side? Have you changed out the water separator and canister filter? Have you replaced the return fuel lines?

 

[Guyfang]

Seafoam is cheap. Try that before doing anything else. Are the IP's adjusted right? Use an IR gun to see if the jug temps are close to one another.

 

[Light in the Dark]

Seafoam is cheap. Try that before doing anything else. Are the IP's adjusted right? Use an IR gun to see if the jug temps are close to one another.

Yes if you can take a photo of the position of where the main fuel lines (off the hard line from the filter) go into the metering pumps.

 

[Jeepadict]

Thank you both for taking the time to weigh in on this. I took pics as best I could hoping I got what y'all wanted to see.

@Light in the Dark
-I'll get some Seafoam picked up when I go to town tomorrow, fuel tank is 60%-ish full presently. I'll run it thru and report back.
-No signs of wet stacking.
-Hours are 1368.
-Both fuel pumps are the round type, particle filter only on the Aux pump.
-Air/oil/fuel canister filters and water separator are all new.
-Return lines have all been replaced.

@Guyfang
-I'm not yet intimately familiar with the processes of adjusting the IP's (injection/metering pumps?) but I got photos as LITD requested. I've perused the task 3-14 of the engine TM for "injection pump timing" and it appears to be rather involved. Neither the injectors nor the injection/metering pumps have been messed with at all post-auction.
-An IR gun is not yet in my box of tricks, but I Amazon'd one today...it will be her Friday. I'm uncertain of exactly where I'll need to measure the jug temps, but I'll do my best and get back to you.

Side note: I found another thread describing the same symptoms and @kloppk dropped some tech wisdom, but OP didn't post their results so the thread just died. https://www.steelsoldiers.com/threads/mep-802a-overload-capacity.133584/

ST

 

[DieselAddict]

Check and see how much fuel you have returning to the tank with it not running in prime and with it running under some load. It’s ok for the return flow to drop a little but you should still get a nice stream back to the tank.

 

[Light in the Dark]

So the metering pumps appear to be clocked correctly... one may be leaking slightly (or its the fuel hose going to the barb, but very slight).... how about the above photo though? Did you let out the tension on the frequency adjustment knob up front? That rotating assembly should be touching or almost touching that other limiting screw when its running at full RPM.

If you haven't let out the frequency cable tension, then you may have a bad cable, or an issue in this part of the engine.

 

[Jeepadict]

So the metering pumps appear to be clocked correctly... one may be leaking slightly (or its the fuel hose going to the barb, but very slight).... how about the above photo though? Did you let out the tension on the frequency adjustment knob up front? That rotating assembly should be touching or almost touching that other limiting screw when its running at full RPM.

If you haven't let out the frequency cable tension, then you may have a bad cable, or an issue in this part of the engine.

There is no fuel leak presently, tho the were multiple when I received the unit. I see some residual behind the pumps...I've had to do multiple evolutions of degreasing on this machine, so I'm thinking that may be what you're seeing. It's going to get another bath once all the work is complete.

Yes, I was messing with the cable adjustment on its last run. I don't recall what it was set at, so I checked its function and took some fresh pics for you at no-load speed. I'll get another round of these for you (hopefully this afternoon) once I get the Seafoam going thru the tank and with a load.

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[justinn]

After an unmotivating winter, I'm making another attempt at this project 802 I have. There was a noteworthy list of problems when I got it, and I'm starting to see the light at the end of the tunnel.

It's a smooth running machine, up until I attempt to go over 74 PRC on the AC Ammeter, then it pulls the engine down below power indicating levels and sometimes will even stall the engine...but never once has it shown any fault lights other than oil pressure AFTER the engine completely stops. Most times reducing the load won't correct the behavior back to normal, I have to remove the load completely before it dies and start again. On occasion when trying to load it the RPMs drop very low but doesn't die, just grumbles along until I open the contact. I'm using a combination of 3 electric space heaters (two ceramic 1000W 110V on opposite legs of the box, one coil wire 5000W 220V) as an improvised load bank (via 50A spider box) to give me flexibility in the load that I apply to the machine. With the engine at full temp, the best truly balanced load I can attain without it dying is 108.2 VAC 18.8A per hot leg using an amp clamp and meter...my math comes to 4068W total. I can get it to pull a slight bit more on one leg (or the other) before it dies, but only 353W worth. When I apply the larger loads I can see the HZ meter drop a bit as I'm used to with my other machine, but where my other 802 will recover and I make slight adjustment to the Frequency Adjust Control this machine just keeps dropping until the HZ meter zeros. Even attempting to max the FAC just before I add a higher load, the machine still bogs down below a functionable level. With all things taken into account, my gut tells me this is most likely a fuel starvation problem...leading me to believe that the Governor requires adjustment or repair.

Disqualifying factors: I've already done a good bit of work to this machine...fixed oil drain line leak, misc wire harness repairs, replaced multiple leaking fuel lines, replaced oil press sending unit, upgraded both well nuts, replaced fuel/oil/air filters and water separator, repaired battery cables, installed new starting batteries, installed missing fuel fill cap, installed many missing case fasteners. All fault lights test good. Remaining discrepancies beyond this low power problem: Oil Press gauge inop, Voltage Adj rheostat bad, and coolant flush. The only thing I have not ruled out yet is the fuel quality, but the fuel is fresh from upgrading the well nuts and I can get the machine to duplicate the failure multiple times over.

In my efforts to scour the TM for the Governor adjustment, the closest task I can find is "4-7 ADJUSTING FREQUENCY DROOP AT ENGINE GOVERNOR". As I'm a big grey airplane guy, and not a ground equipment guy...this is where I find my cause for pause and defer to the judgement of those more experienced than me, because even with the help of the internet I'm having difficulty understanding FQ Droop or the table that depicts the adjustment parameters. I'm all about tinkering, but playing "Parts Darts" is far from my favorite game. Is anyone familiar with this machine's described behavior? When I find the troubleshooting in the TM for a low power condition it flows down a engine failure line of head and valvetrain damage...but that doesn't feel right in this instance.

Thanks in advance! ST

I know it seems kind of stupid, but are you sure that you are on 240v, and not 208v 3 phase? Just because the switch is in the correct position doesn't mean that internally it's not stuck in 3 phase mode. Check the output on the 3rd phase lug with power generation and see if it is showing any output voltage.

I agree with the others about the seafoam though. Throw a couple cans in and run it through..... it's the magic sauce for cleaning up the IP's and injectors.

Justin

 

[Ray70]

In addition to everything else stated above, I would also try loosening 1 injector line at a time while it's running, just to make sure you're firing on both cylinders. Crack 1 line, RPM should drop as engine stumbles. Tighten and repeat on the other cylinder. Your problem definitely sounds either fuel delivery related. Being that a diesel just needs air fuel and compression to run , it won't be that hard to figure it out.
If it stumbles when both lines are loosened, check fuel flow to the metering pumps. If that looks good check fuel pulses out of the metering pumps. If that looks good too, check fuel spray pattern out of the injectors.

 

[justinn]

Is there any surge when it starts happening? or it just drags down to full stall? I had an 803 with a sticky IP rack, but it would surge prior to stalling under load. Also had an 803 with a sticky IP, but it pretty much did the same thing. The 802's since they have half the cylinders may just stall out completely.

If I put much more than 6500 watts on an 802, I can usually get it to drag down like you're talking, and sometimes even releasing the load(if I waited too long) it would drag it down to stall.

Justin

 

[Jeepadict]

Well, fellas...12.7 hours added to the meter over the last day. Last night was a full can of Seafoam and 4 oz of Hot Shot Secrets to a half tank. Today was a full fresh tank with the same dosages, tank is back down to where I started last night. Last night I was finall able to get it to take a load at 80 PRC before i called it a night, but today I couldn't get it above 75...guess that's better than the 70 it was before.

I owe a couple of y'all some direct replies, but I'm just out of time as I'm back to work for the next 9 days straight. I'm going to try my best to pick this up again on my next days off.

Edit: I was typing this update while i was letting it cool down. A new symptom showed itself when I flipped the switch to shut it down...and it didn't. Even the e-stop didn't kill it. Cut-off solenoid had done its job, but for some reason it was still getting enough fuel to stay running. Perhaps that stop screw needs a turn in or two.

Moral of the story: if it has tits or tires, it's gonna give you problems. ST

 

[Jeepadict]

Is there any surge when it starts happening? or it just drags down to full stall? I had an 803 with a sticky IP rack, but it would surge prior to stalling under load. Also had an 803 with a sticky IP, but it pretty much did the same thing. The 802's since they have half the cylinders may just stall out completely.

If I put much more than 6500 watts on an 802, I can usually get it to drag down like you're talking, and sometimes even releasing the load(if I waited too long) it would drag it down to stall.

Justin

How did you remedy the sticky IP rack?

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[Digger556]

Jeeepadict,

I notice your location is Round Mountain, NV and some Google'ing shows your elevation somewhere between 5000 and 7000 ft ASL. NA engines lose 3% of their output per 1000 ft of elevation. Now the MEP generators have some overhead built into their design, but they do have a derating curve if you look at the nameplate. Is is possible, part of your problem is your location?

 

[Jeepadict]

I had a great reply all typed out and the app froze...lost all the awesome, gonna try to do it again.

I've shared your thoughts before when I was doing my initial testing on my other/first 802. At our previous residence in N AZ at 6860 ft I was able to load it at 110 PRC with a resistive-only load. According to my lessons as i understandthem, resistive load is 80% of rating since the sets are spec'd at 0.8 PF. The 802 sets should produce 130% or 6500W non-resistive for 8 (+/- 2) minutes before they shut down on an inverse time principal for the overload protection.

Current living room couch altitude is 5710 (+/- 40), and tho I'm a little over 5000 I'm well less than 95 degrees. So I'm missing roughly 1000W or about 30% rated current.

This set behaves like it's a mechanical failure since there's never any overload fault indicaton and I can repeat the behavior on demand like a light switch on and off where the inverse time overload protection that these sets have in their design never has a chance to function.

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[Digger556]

As a point of reference, I'm at 5280 ft and my 802a will only pull 6200-6300 watts before the engine bogs down and eventually stalls. It will stall without tripping the overload light.

Can you post a video of your unit running and then getting stalled by a load? I think seeing it happen and reading the exhaust will tell a good story about what is going on. Black smoke, even or uneven pulses, etc.

 

[Jeepadict]

As a point of reference, I'm at 5280 ft and my 802a will only pull 6200-6300 watts before the engine bogs down and eventually stalls. It will stall without tripping the overload light.

Can you post a video of your unit running and then getting stalled by a load? I think seeing it happen and reading the exhaust will tell a good story about what is going on. Black smoke, even or uneven pulses, etc.

Sounds like same symptoms, yours just pulls more before it starts. Will it pull that 6300 for as long as it has fuel? I'm inclined to think mine is fuel related, ex sticky IP rack. A buddy in Phx who works on these often suggested cleaning the contacts in the phase switch behind the control pnl...got some Deoxit, gonna give it a go. Not looking forward to digging into the IP rack, also don't have any of the other fuel diagnostics like pressure gauges n such to do deeper stuff. I'm a grey airplane guy by trade, wrenching on ground equipment this deep is virgin territory.

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[Guyfang]

This set behaves like it's a mechanical failure since there's never any overload fault indicaton and I can repeat the behavior on demand like a light switch on and off where the inverse time overload protection that these sets have in their design never has a chance to function.

And what happens, when before putting it on load, you snap up the S7? Then apply load. Will it continue to run?

 

[Jeepadict]

Update for the day:

Last night took some Deoxit to the S1, S6, and S8 that I was suggested to do.

Today I set out for videos and ruling-out the S7. Flipped the S7 switch, indicator light came on as expected, had no effect.

Video 1 was just to see it run and try to document the behavior.

Video 2 was some clarification I thought I missed on the first.

Shut the set down when I went to get my Kill A Watt meter. Got back and found the ceramic heaters to be pulling 1140W-ish on high, and 740W-ish on low.

Now here's the odd part: with the shop heater on high/5000W, I can now get it to pull over 85% on one leg. I have the ceramic heaters plugged into opposite legs on the spider box...both on low and it boggs down, but put one on high on leg 2 and the PRC meter climbs to 90 and holds! Now the part I find odd, shut #2 off and try #1 on high and it won't hold. Confirmed the findings by swapping plugs and the behavior remained.

Tank is down to 20% so prob another round of Seafoam and Hot Shot Secrets.

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[Jeepadict]

And then no sooner does my last update post and I look over and it has bogged down again shaking like crazy because I didn't catch it in time, and now it's back to not wanting to load over 80%...ugh!

Edit: crap, totally forgot to check heat temps with the lazer gun...double ugh!

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