MEP 805A Fuel Help Please!

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mgreene

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Hello all. I am new to this group and looking for some help on a 1999 gen set that we received from the Forestry Service for my local volunteer fire department. It has been sitting for several years. All fluids were empty so we started by filling with oil, water and adding good batteries. I added fuel and started pumping the helper pump as well as spinning the engine and couldn’t get anything to pump. Ended up going to local JD dealer and getting a new pump and filter. That fixes getting fuel to filter. Then replaced the line from pump to filter due to a hard clog and a small hole in one of the bends. I now have fuel to the end of the Stanadyne injection pump but can’t get it any further! The solenoid that activates the shut off doesn’t seem to work but I have moved it in both directions and still get nothing to come to the bolt on the side of the pump (I thought it would be a bleeder port) or to either of the fuel lines that go to the injectors. I did remove the end off the pump this afternoon and checked the small screen strainer inside. Small amount of dirt but nothing terrible? I have tried spinning it from the manual switch located near the injection pump as well as the main switch on the control panel. I’m not sure about the 2 electrical wires that attach to the top of the pump or what I should be seeing there (if anything)? I’m not sure if my next move is to hunt a new pump or if there’s something we don’t have in the proper position to let fuel come through the pump? This will be a great addition to our department if I can figure out what’s happening with it so we can check the charging system?? Thank you for any help anyone can offer us!!
 

robertsears1

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On my 804a generator, your symptoms along with still not getting fuel would point me to checking the magnetic pickup (mpu). Sometimes the magnet collects funk so that it does not see the motor spinning and doesn’t let the fuel pass. On the 804a, it is on the same side as the injector pump and is about a 3/8” threaded stud with two wires going to it that is mounted on the generator body just past the engine. The books are available for download. It should give a certain range of voltage while cranking the engine with the dead crank switch. Not exactly sure how it is done with the JD engine but the theory should be similar in that it has to see the engine spinning to let fuel through, at least on the newer generations of engines.

Robert
 

mgreene

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Thanks Robert. I will look at that this afternoon. My only question to that is that since my electronic sylinoid doesn’t work, and I’m manually moving the shutoff back and forth to try and get fuel through it,,,,will that bypass the electrical problems from the switch your talking about? Thanks again for the response.
 

mgreene

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Cerro Gordo NorthCarolina
I downloaded it from here last night. There is a lot of good useful information in it, but I didn’t find much on the injection pump itself. I really feel that something in it is stopping the fuel, just never had any experience with this type of pump so I’m not sure how far I can tear into it without going too far. With all of the stuff I found here for other models hopefully someone will help us in the right direction!!
 

mgreene

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Cerro Gordo NorthCarolina
Any more ideas or knowledge on this type pump?? Would love to find a parts breakdown or at least someone that has opened the top of one? Maybe a little direction on the correct way to position the manual shutdown to be in run position or what is under the wires going in the top and could it be stuck?? Thanks in advance!!
 

Guyfang

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I downloaded it from here last night. There is a lot of good useful information in it, but I didn’t find much on the injection pump itself. I really feel that something in it is stopping the fuel, just never had any experience with this type of pump so I’m not sure how far I can tear into it without going too far. With all of the stuff I found here for other models hopefully someone will help us in the right direction!!

Any TQG that turns over, but not start, should have the MPU mesured for proper voltage, pulled, cleaned installed and adjusted. That is the very first thing I would do. That solves 95% of the no start problems.
 
Last edited:

Guyfang

Well-known member
7,297
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Location
Burgkunstadt, Germany
On my 804a generator, your symptoms along with still not getting fuel would point me to checking the magnetic pickup (mpu). Sometimes the magnet collects funk so that it does not see the motor spinning and doesn’t let the fuel pass. On the 804a, it is on the same side as the injector pump and is about a 3/8” threaded stud with two wires going to it that is mounted on the generator body just past the engine. The books are available for download. It should give a certain range of voltage while cranking the engine with the dead crank switch. Not exactly sure how it is done with the JD engine but the theory should be similar in that it has to see the engine spinning to let fuel through, at least on the newer generations of engines.

Robert
Robert,

all TQG's have MPU's, and all are adjusted the same way. No mater what engine, same procedure.
 

robertsears1

Member
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Location
Near Apex/NC
Here is the MPU on my 804a. In this case, the crap on the end was the problem. Another time the end had been damaged and I had to replace it. Pictures would help. Below where you type a message, hit go advanced, then hit manage attachments, then upload your pictures. If I can do it , anyone can!
Robert
 

Attachments

mgreene

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Cerro Gordo NorthCarolina
So here is my update after about 4 more hours of aggravation this afternoon! I started with the MPU. Upon touching the wires one of them fell out of the connector so I quickly repaired that thinking I had found my issue. No difference! I checked the ohms and only get around 1.3 ohms between the 2 wires so I’m guessing it is bad anyway? I am completely hard headed and could not get it through my mind how this could stop my fuel when I had run a 24v jumper straight to the injection pump shut off in theory bypassing the complete starting system on the machine. I had to dig a little deeper! I removed the top cover from the IP that houses the electric solenoid and found everything inside completely frozen up from water I suspect? I sprayed everything with blaster and began to pry things back and forth ever so slightly. Then I moved the shut down linkage to the point I thought should be on and I immediately got fuel out the injector side of pump! After a little bleeding I was able to fire it up! The internal linkages are still kinda tight to slide back and forth so I coated everything good with penetrating oil and left it to sit. I wanted to see if the generator would generate but not sure it will work before I replace the MPU? I don’t know the exact startup procedures for this unit? There is no documentation on the unit that I have found? I guess I will see what I learn tomorrow!
 

Guyfang

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You are assuming. Don't assume the MPU is bad, till you test it. What you need to do is read the TM. But since you won't, try testing the MPU. Disconnect both wires from the MPU. Connect a multimeter to the wires set up for AC voltage. Have someone use the S10 dead crank switch to spin the engine over. You should get 3 volts AC from the MPU if it's adjusted right. Having seen Roberts pictures, you can see, the MPU can pick up grease, dirt and metal chips. I would pull the MPU first, to ensure that it dosnt look like Roberts picture. That can and will through off readings. Clean it first. Then screw it down until you bottom out. Turn it back 3/4 turn, (I always do a full turn, as I am that way) then lock down the nut, hand tight. Have someone spin the engine. What you want is 3 volts AC. If it's low, then turn it in, a tad. Test. Low, turn it in a tad. You get the picture. Turn it too far in, you get to buy another one. Get it adjusted right, lock it down.
 

mgreene

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Cerro Gordo NorthCarolina
I did remove it after to check and everything looked clean. I saw someone had posted the ohm reading should be I think between 900-1200. Mine being only slightly over 1 I was already sourcing a new sensor? I have been reading through the 300 page books but by the time my internet gets one downloaded and open, and I search through it, I’ve just not run across the right one yet. I will get the sensor sorted later this afternoon I hope as well as freeing up the internals on my injection pump so we can start checking for voltage. I found last night, I have a parts unit about 20 miles away at a neighboring fire department that quit generating but has a good running engine so at least I have a few parts available! Thanks
 

mgreene

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Cerro Gordo NorthCarolina
I was able to pull up each manual Regis morning before my kids got up and overloaded my internet speed! I will re check ohms in the control panel this afternoon as well as voltage and see where I get from that. Any additional tips on freeing up the governor or shutdown parts in the top of the injection pump? I’m not 100% sure how free these linkages should be or if I need to go further down the IP to clean any of the rusted areas up? This is a great website and I’m so glad I found it! Hopefully by hurricane time this year we can be ready!!
 

Guyfang

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I would get a good MPU and install and adjust it. You can by one from trucking repair shops. There is a thread where 155mm had the same problem and where he bought his replacement. Perhaps Robert can also chime in here. Then give it a try. Since you have removed the actuator, keep in mind that it has to go back in right. The yoke has to slide in just right, to actuate the IP. If you get it in wrong, wont start. So look at it real good before you start, take your time. Once you do it one or two times, its easy. Unless the top of the IP is rusted up, it should be OK. The MPU is the key to the whole set. It doesn't work right, NOTHING works right on the set.
 

mgreene

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Cerro Gordo NorthCarolina
So here is what I have learned today. The top of the IP does have a fair amount of rust. After soaking last night in penetrating oil, everything moves a little more free than it did but it still needs more soaking/ working! I re installed the MPU per TM direction and then disconnected the two wires from the governor control unit and had approximately 1.3 volts while cranking. I re adjusted it and got it up to 2.3 volts by screwing it in 1/8th of a turn. I still have the top off the IP so I’m controlling the engine rpm and shutdown manually at this point. I started the engine and let it warm up a few minutes and tried to close the switch to activate the generator and nothing?? I tested the bulb and it does burn. I found the info in the manual on ohming the switch and it seems to work fine. Have not found what lines I should be seeing voltage on or how to check that? The 6 connector switch only has 4 wires hooked to it. I have 24volts on the #2 and #3 connection but nothing on the ones hooked to #5 or #6. No idea how to even begin diagnostic testing on the generator side? I have slight electrical knowledge but do have a decent digital meter? I will start reading through the info in the TM’s for my next move on this? Thanks again everyone!
 

Guyfang

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I know I am going to sound like a nag again. But you need to read the book. In the operators manual it explains how this set works,

When you turn S1 on, to the start position, a number of things happen. But the MPU drives them all.
1. The MPU tells the Electric gov. To start the engine. Without the apron 3 VAC signal, the from the MPU, the electric Actuater will not get a signal from the elect gov, set will not start.
2. At a predetermined RPM, the MPU tells the electric gov to kick the starter out of operation.
3. You have to hold the S1 up longer on TQG's to get excitation, so when the starter gets kicked out, the MPU also tells the electric gov to allow the initial excitation to happen. That voltage comes from the S1.

The he most commen reason no output voltage is people do not hold the S1 up long enough. So if you did not hold up S1 for 4-5 seconds longer then the starter ran, that might be a reason.

Also, is the Quad MWO installed on your set? Have you checked the fuse?
 
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