Can anyone tell me if their MSU 500 F-PUMP cycles when...

[IslandHopper]

Can anyone tell me if their MSU 500 or 700 fuel pump and injector cycle when you turn the key on? This will help me rule out the Crank Position Sensor as a problem.

I just bought this non-running and the service manual is not much help.
Thanks

[IslandHopper]

My thinking is that if they are supposed to cycle with just the key to the RUN position, then it would not be the CPS.
 

[T-boss 410]

You should hear the fuel pump run for a few seconds when you turn the key to the run position. It's building up the pressure for starting the engine. 

[IslandHopper]

Thank you for the reply. That was my thinking but I just bought this one as-is so I wasn’t sure. The service manual doesn’t say much but I’m thinking the only part that would effect the fuel pump, injector and spark would be the ECU. I thought possibly bad ground but it looks ok and the engine cranks over great.

 

[T-boss 410]

If your not getting spark or the fuel pump isn't priming, you may just have to replace the ECU. There may be some way to test it, but I certainly don't know. I'm flying blind with mine. Don't want to pay for the manual if it ain't worth it. 

[IslandHopper]

I was not worth the money.  It’s way too vague. Thanks 

[Joe Breaux]

If you bought an MSU 500, you will soon see ITS NOT WORTH IT ... Ihave had problems since the 1st day I bought it new. at Tractor Supply .. and Massimo has refused to pay one dime of repairs .. its been in the only repair shop in my state that will still even work on Massimo, 6 times  .. and only if you pay cash.. 

[IslandHopper]

Wow Joe. You’ve been a lot of help Dumba**

[Joe Breaux]

4 minutes ago, IslandHopper said:

Wow Joe. You’ve been a lot of help Dumba**

forewarned is forearmed.. ....but obviously you have always been UNARMED .. but good luck, maybe you can cuss it into a good machine .. 

[Ben1098]

Find the Delphi ECM.  Should have 2 connectors----gray and black.  There are two +12vdc inputs.  One (pin 18) is ALWAYS HOT (like memory on radio) and then the other(pin 15) is hot only with KEY ON.  Don't have ECM pin out handy so I can't state which color connector.  With KEY OFF, remove both connectors (identical except color) and find the fine print molded pin numbers.  KEY ON.  Needle probe (don't stab and ruin the terminal) the pin(s) number looking for the 2 +12v inputs.  After finding, KEY OFF to see if pin 15 goes away (check to see if you are in the right track).  Problems found in past....fuse blown, smashed connector, mouse house chews, and loose connector. 

There is not a good wiring diagram.  The same DELPHI ECM module (retuned) is on late B & S   FI   V-Twin lawn mower engines and the pinout can be found with YAHOO search using  DELPHI ECM PINOUT.

Without the two supply pins, the ECM plays dead....check before spending $$$$$$$$$$$$$$$$$.  CHOW

 

[IslandHopper]

Ben...Thanks a lot for the info! I’ll check it out. 
Joe... This post is asking “does the fuel pump cycle when the key is in the run position”  NOT  “what’s your opinion of Massimo”

I know it’s not the same quality as my Teryx,  It’s a project machine that I payed $200 for.

[Ben1098]

I bought an almost NEW swimmer....drunk fishing buds went to river....to not get a DWI....left MASSY at river....best part....left keys in the ignition....river sandbar recovery.  Hoped for best with this pig in a poke.  Sanded piston/cyl.  Crank bearings "rough".  Even the transmission bearings had multiple  bind spots.  New oil pump.  Still money ahead.  The rear output shaft was leaking BEFORE the swim by the oil slick on present.....BTW, watch this very close....sealant gets hard and leaks not at the seal BUT thru the spline...NICE.  That was 4 years ago....keep the oil level up and CLEAN and watch for air lock in coolant.  Special bleed procedure...FRONT RAISED about a foot...makes radiator higher than engine head bleed screw.  The Al tubes that run in the bottom floor pan HAVE TO HEAT UP WHEN WARMING UP MOTOR....this means the coolant is flowing to the radiator.  BTW, it is a YAMAHA RHINO clone with motor parts interchangeable......I suspect the cam with it's compression release was made by the same SUB......I worked on BOTH units that the weld assy step was WRONG EXACTLY IDENTICAL.....so my spare cam (modified/fixed) went into a RHINO.

My experience......they all have problems (repeat problems)...worst is hillside + idle oil failure (crispy head).  Back to RHINO/HISUN (these motors are in everything....big box).  Common failure in R, Hisun fixed with a more robust bearing so these parts are not interchangeable.  Electrical problems...don't go there.  Ho would not start while cranking....will catch when starter is released.  Even a "solid" design will fail when the starter hot cable is bundled with the pickup coil signal wires.....same as a RAM with the alt cable trashing the ECM inputs.  Gotta go.

[Joe Breaux]

1 hour ago, IslandHopper said:

Ben...Thanks a lot for the info! I’ll check it out. 
Joe... This post is asking “does the fuel pump cycle when the key is in the run position”  NOT  “what’s your opinion of Massimo”

I know it’s not the same quality as my Teryx,  It’s a project machine that I payed $200 for.

Dont care if it was $1 at Kroger, still no excuse to call ANYONE dumba^^  .. Its still America, we can still have an opinion other than yours ... please disregard any post I make in future.. it wont be for you 

[cliffyk]

On 2/3/2021 at 9:14 PM, T-boss 410 said:

You should hear the fuel pump run for a few seconds when you turn the key to the run position. It's building up the pressure for starting the engine. 

FWIW--This is how my Hisun  HS400 works,,,

[IslandHopper]

Thanks! 
I have power to the fuel pump, ignition coil and everything else. I Installed a new Relay unit &  a new ECM and that didn’t change anything.
I’m starting to think the problem may be a bad ground. I haven’t been going that direction though because the starter cranks and all other options and accessories have power. I’ll post more later. 

[cliffyk]

On 2/20/2021 at 10:13 AM, IslandHopper said:

Thanks! 
I have power to the fuel pump, ignition coil and everything else. I Installed a new Relay unit &  a new ECM and that didn’t change anything.
I’m starting to think the problem may be a bad ground. I haven’t been going that direction though because the starter cranks and all other options and accessories have power. I’ll post more later. 

The "power to the ignition coil" should switch on and off while cranking the engine. The ECU cuts power to the coil when it's time to fire the plug--the collapsing magnetoc field in the coil primary generates the high voltage pulse in the secondary to fire the plug. If the voltage at the coii's primary is unwavering that is not happening.  Have you tested the coil's secondary to see if there is a spark?

DEpending on how the ECU uses the CKP it is possible that a bad sensor could prevent a spark. Most of these small engines have no cam position sensor and use the crank sensor to trigger the spark, this means it fire at each near TDC of the crankshaft but one of these firings is at he top of the exhaust stroke and does nothing. This is often called a "waste spark" ignition system. It is common in  multi-cylinder 4  stroke/cycle engines to use one coil to fire two plugs on two cylinders that reach TDC at the same time by wiring them in series.

wasted spark ignition

 

 

 

[IslandHopper]

Thanks for the help.
So there is no spark on the secondary side when cranking. I’ve been trying to figure which wire or wires in the harness would effect  all 3, (fuel pump, ignition coil, and fuel injector) I am told that the crank position sensor should not effect the fuel pump or injector cycle? but no one seems to know for sure. 

[Ben1098]

ECM most likely not getting 12v on BLACK connector at 2 places.  Always Hot on p. 18 and also p.15 with KEY ON.  Either missing ECM is non working.

[cliffyk]

4 hours ago, IslandHopper said:

Thanks for the help.
So there is no spark on the secondary side when cranking. I’ve been trying to figure which wire or wires in the harness would effect  all 3, (fuel pump, ignition coil, and fuel injector) I am told that the crank position sensor should not effect the fuel pump or injector cycle? but no one seems to know for sure. 

What model year is your MSU500?

 

[cliffyk]

The fuel pumps an the majority of these small EFI engines are not "controlled" externally--I.e. they have just one mission in life; which is to, when powered up, keep fuel line pressure at or about 3 bar¹ (43.5 psi)--if it isn't they run 'til it is.

Have you tested the fuel pump, ignition coil,  and injector individually to see if they are capable of doing what they are supposed to?  If direct wiring shows them them to be operational the problem has to lie in getting power to them in normal operation. It would be quite a coincidence for them to all fail at once, but a Forrest Gump said "It happens". you could also connect a dedicated ground to each and see what happens; ground connections are often overlooked--and just because the engine cranks does not mean all low current ground paths are intact.

-------------------------------------------------------------
¹ - 3 bar is the standard pressure used for fuel injector delivery ratings. Most makers use it or near--39-40.5 psi is not an uncommon spec (Ford likes 39)--in their fuel systems.

 

[IslandHopper]

This is a 2017

[cliffyk]

Do you know if it was made by Hisun? I'm trying to find a valid wiring diagram to help out...

There should be an EPA certification sticker someplace on the machine (typically under the "hood")  that indicates who actually made it.

THis is that sticker from my 2020 "Coleman" UT400 (showing it to be a "Hisun" brand actually made by the Vietnam New Century Industrial Company:

[IslandHopper]

[IslandHopper]

Unfortunately it doesn’t tell me who made it.

[cliffyk]

1 hour ago, IslandHopper said:

Unfortunately it doesn’t tell me who made it.

It does indirectly, this (below) is from the EPA website--it's from their certification data worksheet:

It shows the engine was made by: Chongqing Huansong Science and Technology Industrial Co., Ltd. -- I.e. Hisun

I'll see what I can find for a valid wiring diagram...

-cliff-

 

[cliffyk]

The CKP is a magnetic pickup coil mounted alongside the alternator stator--it reads the interrupted tooth pattern on the rotor's rim to generate a 5 V square wave signal for the ECU: 

The missing tooth creates a missing pulse to indicate Top-Dead-Center (TDC).To properly test it you  need an oscilloscope to monitor the output waveform, but check its connector (a smallish 4-termial plug w/only two wires (black and blue) that should be close to the alternator output connector (a largish round connector w/ three wires).

[IslandHopper]

This is great info. Thanks a lot! I’ll test it this weekend.

[Ronniecross]

I'm having this same issue, there is a white wire wit black stripe and black wire with red stripe and the black wire isn't getting its ground but I'm not sure where those wires go because the go into main harness up top. Any ideas on why I have no ground and when I do ground it it still doesn't spark.

[klm]

I'm easily confused, you said you had power to the fuel pump but does it cycle when you turn on key?

[Kenh]

It could possibly be in the fuse box. Mine is under the hood fuse and relays

I had to replace mine