I won an auction last week on a 900 hour 803A that ran. The frequency and voltage tend to fluctuate slightly. I have found a tremendous amount of good information so far on the site, but I'm still struggling. My initial though was a fuel issue. So far I've: replaced the fuel pump, replaced the primary and secondary fuel filters, followed the TM for bleeding/priming the system, checked fuel tank cap, installed fresh fuel with Sea Foam additive, & checked air filter. The unit really struggles above 75% load, to the point the frequency tanks. I've attached a video of the unit starting. In the second video listen to the sound just after I close the right hand door. Is that concerning? I'm not sure what rock to look under next. Any insight would be greatly appreciated, thanks.
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803A Not Running Steady
- Thread starter zenerknee
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The second video link doesnt work.
I hadn't clicked the final save button. Hopefully its fixed now.
Ray70
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In the video's it appears to be running OK at no load.
Do you have a video of it as it starts to die out under load?
I have experienced several 1074 fuel pump issues lately where the machine will run fine for a while but above 50% load the machine will run a little while then slowly die down.
What did you use for a replacement pump?
Another possibility is an issue with the governor setting or possibly an injector or weak cylinder issue.
If you get a video of it petering off, that would be helpful for us to advise better.
Do you have a video of it as it starts to die out under load?
I have experienced several 1074 fuel pump issues lately where the machine will run fine for a while but above 50% load the machine will run a little while then slowly die down.
What did you use for a replacement pump?
Another possibility is an issue with the governor setting or possibly an injector or weak cylinder issue.
If you get a video of it petering off, that would be helpful for us to advise better.
uniquify
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Here are a few more questions that might help us diagnose what's happening:
Is there any junk in the fuel tank that could be blocking / restricting fuel flow into the pickup tube?
What color is the exhaust smoke when it bogs down? (White, blue, black, clear...)
Are both batteries well charged?
Also, do you have access to a mechanical fuel pressure gauge? I'd be curious to see if the fuel pressure is steady before/during/after the engine is bogging down.
Is there any junk in the fuel tank that could be blocking / restricting fuel flow into the pickup tube?
What color is the exhaust smoke when it bogs down? (White, blue, black, clear...)
Are both batteries well charged?
Also, do you have access to a mechanical fuel pressure gauge? I'd be curious to see if the fuel pressure is steady before/during/after the engine is bogging down.
robson1015
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Good point - couldn't believe the sand, junk that was in the fuel tank of my unit.
Ray70,
The unit run OK, but the slight variations in voltage and/or frequency wreak havoc on my computer UPS. Granted, its a cheapo UPS; I've got a rack mounted one that does fine with it. I have seen videos of others machines with rock steady voltage frequency up through and past 100% load.
The original fuel pump shorted after 1.5 hrs run time. I replaced it with an Airtex E8131. I had hoped that would clear up my issues. When it didn't, I replaced the two fuel filters. That didn't seem to affect it either.
I've been using my house as a load, as I've only had the unit 10 days now. I have a lot of electronics and I'm hesitant to experiment further for fear of frying something. I plan to scrounge up some heaters for a 'dummy' load and will get a video.
In the meantime, I ran it for about 5 minutes unloaded today and took some temperatures of the exhaust manifold. See attached.
The unit run OK, but the slight variations in voltage and/or frequency wreak havoc on my computer UPS. Granted, its a cheapo UPS; I've got a rack mounted one that does fine with it. I have seen videos of others machines with rock steady voltage frequency up through and past 100% load.
The original fuel pump shorted after 1.5 hrs run time. I replaced it with an Airtex E8131. I had hoped that would clear up my issues. When it didn't, I replaced the two fuel filters. That didn't seem to affect it either.
I've been using my house as a load, as I've only had the unit 10 days now. I have a lot of electronics and I'm hesitant to experiment further for fear of frying something. I plan to scrounge up some heaters for a 'dummy' load and will get a video.
In the meantime, I ran it for about 5 minutes unloaded today and took some temperatures of the exhaust manifold. See attached.
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The 4 soft fuel lines that come from the fuel filter, to each metering pump... are all 4 of those pushed all the way towards the engine (possible almost touching the push rod tubes) on all 4? If those lines are in different positions, it can cause uneven fueling.
Uniquify,
I'll investigate the pick up tube. I will say, in the process of bleeding the fuel system, I had a lot of flow.
I will take note of the smoke color when I get the dummy load set up.
The batterys are brand new and fully charged.
I don't have a fuel pressure gauge, but I'm not opposed to picking one up. Anywhere in particular you'd want to see the reading from (just after the pump?)?
I'll investigate the pick up tube. I will say, in the process of bleeding the fuel system, I had a lot of flow.
I will take note of the smoke color when I get the dummy load set up.
The batterys are brand new and fully charged.
I don't have a fuel pressure gauge, but I'm not opposed to picking one up. Anywhere in particular you'd want to see the reading from (just after the pump?)?
Ray70
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Good call, don't use your house as a load bank when working on the machine, bad things can happen.
It is very hard to accurately diagnose things from an audio clip, but it does sound like the engine is fluttering somewhat, and possibly another odd noise, but sound can be deceiving when listening on the computer.
Cylinder temps can be very useful, but don't be fooled by that hot spot near cyl.3 it could simply be the fact that there is more heat as you get closer to the outlet into the muffler.
Cylinder temps taken at the underside of the exhaust ports in the head tend to be more accurate, but still you need to be cautious of temp errors caused by more airflow towards the front of the motor. And take the temp while under a heavy load, that will tell you a lot more about fuel distribution.
As LITD mentioned, if the inlet line to any of the metering pumps appears substantially further from the pushrod tube than others, that pump will be supplying more fuel to it's cylinder than the others and should show us as being a bit hotter than the other cylinders.
At first start up, do you get any smoke other than the initial puff of black at first? Any noticeable grayish smoke at all after the first 2 or 3 seconds?
Once you get a load test set up and give us some more info on smoke color, temps etc. we should be able to tell more.
Also, next time you run it under a load, try cracking the lines coming off each metering pump, one at a time and see if the motor stumbles as you crack each line.
If you crack any line and nothing changes, that cylinder is not firing correctly.
It is very hard to accurately diagnose things from an audio clip, but it does sound like the engine is fluttering somewhat, and possibly another odd noise, but sound can be deceiving when listening on the computer.
Cylinder temps can be very useful, but don't be fooled by that hot spot near cyl.3 it could simply be the fact that there is more heat as you get closer to the outlet into the muffler.
Cylinder temps taken at the underside of the exhaust ports in the head tend to be more accurate, but still you need to be cautious of temp errors caused by more airflow towards the front of the motor. And take the temp while under a heavy load, that will tell you a lot more about fuel distribution.
As LITD mentioned, if the inlet line to any of the metering pumps appears substantially further from the pushrod tube than others, that pump will be supplying more fuel to it's cylinder than the others and should show us as being a bit hotter than the other cylinders.
At first start up, do you get any smoke other than the initial puff of black at first? Any noticeable grayish smoke at all after the first 2 or 3 seconds?
Once you get a load test set up and give us some more info on smoke color, temps etc. we should be able to tell more.
Also, next time you run it under a load, try cracking the lines coming off each metering pump, one at a time and see if the motor stumbles as you crack each line.
If you crack any line and nothing changes, that cylinder is not firing correctly.
Howdy,
You could also have a unit which is gummed up. Wet stacked. If you use your house, have all breakers off except your stove. Or find a junk yard stove. Gradually raise the power. If it dies off at 75%, go back and run it at say 65% for some hours. Then keep adding a little more load at a time. You will start seeing black specs raining down as the exhaust ports and muffler start cleaning up. The diesel like to be run at 60-100% hard. Keeps them cleaned up. I always found my inner cylinder temps were some degrees higher than the rear cylinder. (closest to the control box)
After a while you should be able to maintain a 100% load.
If you find one of my videos. I had a unit so clogged up, I removed the exhaust manifold and scrapped and power washed it. Even with it clean, and loading it up, I got all the black carbon raining down from what was in the muffler. Now it runs good and strong.
You could also have a unit which is gummed up. Wet stacked. If you use your house, have all breakers off except your stove. Or find a junk yard stove. Gradually raise the power. If it dies off at 75%, go back and run it at say 65% for some hours. Then keep adding a little more load at a time. You will start seeing black specs raining down as the exhaust ports and muffler start cleaning up. The diesel like to be run at 60-100% hard. Keeps them cleaned up. I always found my inner cylinder temps were some degrees higher than the rear cylinder. (closest to the control box)
After a while you should be able to maintain a 100% load.
If you find one of my videos. I had a unit so clogged up, I removed the exhaust manifold and scrapped and power washed it. Even with it clean, and loading it up, I got all the black carbon raining down from what was in the muffler. Now it runs good and strong.
Interesting! I do always find a bunch of carbon on top of the unit after running it.
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Clear sign of wet stacking. There are other reasons for the carbon build up. But you need to run this baby under load, for mutable hours, to see if that the problem.
Update:
Got the pressure gauge. Got a small load center and some heaters.
I've been running it as hard as it would allow. Was still struggling to get above 75% load and frequency was up and down plus and minus 2 hz.
I made up a punch list of things from all of your suggestions. In working through the list, I was draining the fuel tank; using the new fuel pump to pump into a bucket. When the fuel level in the bucket rose above the end of the hose I was using, I noticed bubbles coming through. EUREKA!
Fixed the leak on the suction side of the pump. Ran 110% load with frequency steady to the tenths of a hz! Even my cheap-o UPS is happy.
THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU ALL FOR YOUR HELP!
Ultimately, I went from a faulty fuel pump to a new fuel pump with a leak, which presented the same symptoms. When I replaced the pump, I bought a 90 degree fitting to aid in connecting the fuel lines without having to modify the lines themselves. I hadn't been using teflon tape, because of the flanged fittings; however, the 90 was not a flanged fitting and needed teflon. In my haste, I overlooked it.
Thanks again,
Z
Got the pressure gauge. Got a small load center and some heaters.
I've been running it as hard as it would allow. Was still struggling to get above 75% load and frequency was up and down plus and minus 2 hz.
I made up a punch list of things from all of your suggestions. In working through the list, I was draining the fuel tank; using the new fuel pump to pump into a bucket. When the fuel level in the bucket rose above the end of the hose I was using, I noticed bubbles coming through. EUREKA!
Fixed the leak on the suction side of the pump. Ran 110% load with frequency steady to the tenths of a hz! Even my cheap-o UPS is happy.
THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU ALL FOR YOUR HELP!
Ultimately, I went from a faulty fuel pump to a new fuel pump with a leak, which presented the same symptoms. When I replaced the pump, I bought a 90 degree fitting to aid in connecting the fuel lines without having to modify the lines themselves. I hadn't been using teflon tape, because of the flanged fittings; however, the 90 was not a flanged fitting and needed teflon. In my haste, I overlooked it.
Thanks again,
Z