mep004 strange load response

[sgarfa]

I noticed the problem about the trend of increasing of Hz (And rpm) specially with no load... from 50 to 52hz (i'm in italy) in 2/3 minutes... at the same time if I apply sudden loads of 60/80%, like a welding machine I notice an inadequate tendency not to recover rpm...and the consequent drop of hz... I tried to move the knurled knob...but I would not do things randomly

 

[DieselAddict]

Have you done a proper load test and compared the frequency stability to the manual? Have you checked all the mechanical components of the governor?

Is the engine sound actually changing such you think the RPM itself is changing? Have you verified frequency with an external instrument?

 

[1800 Diesel]

A few things to consider or check:

1. Clogged fuel filters can affect fuel delivery and injection pump function. Have the primary & secondary filters been replaced recently? If so was the system properly bled? This also applies to the fuel strainer--has this been recently cleaned?

2. Water in fuel can also clog filters (hopefully) and cause fuel starvation and erratic injection pump operation. Have you drained the petcocks on the strainer and filter housings? A good way to do this is to drain into a glass or plastic jar so you can better see water presence in the fuel.

3. Trash can also get in the body of the injection pump and cause problems. See previous threads that cover this issue well.

4. Check electric fuel pump function and also remove and clean the screens if this hasn't been done recently.

5. Fuel on these units is supplied via the small day tank (fed by the electric pump) and then gravity flow supplies the injection pump. I've seen this line clog up with debris on the inside of the day tank which restricts fuel flow to the injection pump.

Remember to bleed the fuel system whenever you break a fitting loose for any reason.

I'm certain I didn't cover all possibilities, but just the few that came to mind. Good luck sorting it out.

 

[sgarfa]

in short yes, the engine whit out load tends to accelerate a little, I mounted a new panel instrument between a phase and L0 ... to monitor voltage frequency and working hours ... in any case the increase of hz is noticed both by the new instrument, and also old one ... I honestly do not think it is a fuel alimentation problem,rather than pump or a regulator...

 

[sgarfa]

ehm...Regarding the pump I had disassembled it just to solve an annoying loss of fuel that came from the knurled knob...but before the generator gave these symptoms, I would also revise the pump but I would not do it for nothing .. considering that i willi certainly have trouble finding the spare parts

 

[1800 Diesel]

in short yes, the engine whit out load tends to accelerate a little, I mounted a new panel instrument between a phase and L0 ... to monitor voltage frequency and working hours ... in any case the increase of hz is noticed both by the new instrument, and also old one ... I honestly do not think it is a fuel alimentation problem,rather than pump or a regulator...

Frequency value is directly proportional to engine/generator speed. Increase engine speed, frequency increases; decrease engine speed, frequency drops. You should have 50hz at 1500 RPM; if the engine is "hunting" up and down at this speed, you should see frequency rise and fall in proportion to engine speed changes.

As to you last sentence: "I honestly do not think it is a fuel alimentation problem,rather than pump or a regulator." You don't think it's a fuel elimination problem--or better known as fuel starvation or starving--this means fuel is not being delivered to the injection pump in necessary volume and the fuel line contains air that is interrupting steady fuel flow. In the second part of your sentence, are you saying that you believe the injection pump may be failing or something is malfunctioning in the voltage regulator circuit?

I offered a few possibilities as to what may cause the symptoms you described, but you didn't address these where they could be eliminated one-by-one. There are other possible causes that can be found in the tech manual under troubleshooting, but in my experience (for this particular situation) I find more fuel delivery issues than what the TM mentions. Not saying the TM is wrong, but only that I find more fuel issues than say valves out of adjustment or a dirty air filter.

 

[sgarfa]

@1800 diesel, what you say is absolutely right, only that I premise that i weld the tank and I took the opportunity to overhaul the whole fuel supply .. now the possibility of air in the circuit is possible .. I will check again..

 

[Guyfang]

I noticed the problem about the trend of increasing of Hz (And rpm) specially with no load... from 50 to 52hz (i'm in italy) in 2/3 minutes... at the same time if I apply sudden loads of 60/80%, like a welding machine I notice an inadequate tendency not to recover rpm...and the consequent drop of hz... I tried to move the knurled knob...but I would not do things randomly

There is no governor, per-say, on this model, (MEP-004A) gen set. You have the hertz/engine speed adjustment knob/cable, and that's it. The cable does all the functions of a governor in the sense that it should not let the engine over speed, and it will set an upper limit of engine speed. It can NOT stop it from going lower, because of air in the fuel system, trash in the fuel system, poor performance of the TWO electrical fuel pumps, injector pump and filter system. An electrical governor system would at least TRY and compensate. So if you are losing RPM/hertz, its a fuel problem, or an injector pump problem. When a 004A fluctuates, its normally always fuel problem. You need to check:

1. The gen set fuel tank for dirt and trash.
2. BOTH electric fuel pumps for CORRECT operation.
3. Insure that the fuel strainers in both electric fuel pumps are clean, and that the springs and magnets are in the pumps.
4. Check the day tank for trash and dirt.
5. Check the check valve that is just before the injector pump.
6. Check that the arm on the injector pump moves freely.
7. Remove and check the fuel cut off solenoid on the injector pump.
8. Insure that EVERY connection is tight, and every hose is dry, on the fuel system.
9. DO NOT move the knob on the injector pump, unless you know what you are doing. Read the -34 manual before attempting to "adjust" the knob.

You need to give us a bit more information. Is the set new to you? Have you had it a long time and it just started to act strange?

 

[sgarfa]

There is no governor, per-say, on this model, (MEP-004A) gen set. You have the hertz/engine speed adjustment knob/cable, and that's it. The cable does all the functions of a governor in the sense that it should not let the engine over speed, and it will set an upper limit of engine speed. It can NOT stop it from going lower, because of air in the fuel system, trash in the fuel system, poor performance of the TWO electrical fuel pumps, injector pump and filter system. An electrical governor system would at least TRY and compensate. So if you are losing RPM/hertz, its a fuel problem, or an injector pump problem. When a 004A fluctuates, its normally always fuel problem. You need to check:

1. The gen set fuel tank for dirt and trash.
2. BOTH electric fuel pumps for CORRECT operation.
3. Insure that the fuel strainers in both electric fuel pumps are clean, and that the springs and magnets are in the pumps.
4. Check the day tank for trash and dirt.
5. Check the check valve that is just before the injector pump.
6. Check that the arm on the injector pump moves freely.
7. Remove and check the fuel cut off solenoid on the injector pump.
8. Insure that EVERY connection is tight, and every hose is dry, on the fuel system.
9. DO NOT move the knob on the injector pump, unless you know what you are doing. Read the -34 manual before attempting to "adjust" the knob.

You need to give us a bit more information. Is the set new to you? Have you had it a long time and it just started to act strange?

this is the total answer ... thanks
in any case, the generator has been there for a few years ... but only now I have begun to use it

 

[Guyfang]

I would also dump several cans of injector cleaner fluid into the fuel tank AFTER I cleaned the fuel tank. Do you have a metal tank, or plastic tank? The tank is easy to pull out. Remove the panel in back. Remove the filler neck rubber boot. Be carful with the boot. Treat it nice! Then remove the pickup and return lines to the tank. If you can not remember how they go back on, it's in the manual. I would take pictures. Then simply slide the tank out. I always used a steam cleaner to clean the tank. Do remove the fuel tank level sending unit BEFORE using the steam cleaner, or you will need to buy a new one.