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  1. #1
    pb0000's Avatar
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    NEED HELP with 2003 MSX140

    Hi everyone, can use some help:

    Purchased a MSX 140 (2003) last week, and it idles fine, but when I try to accelerate to WOT about half the time it just lags permanently at close to idle (<10mph). On occasion, it'll just work fine and speed up like normal like it should.

    I've been trying to fix, don't have way to read error codes but am looking into that, nothing lighting on dash as error though. So far I've replaced the TPS, which seems to be a common problem with these machines. That changed nothing. I replaced the spark plugs, cleaned the coil terminals, cleaned the battery cable terminals, changed the battery, cleaned the screen in the coolant, and the throttle cable seems to be fine in it's travel. I checked the fuel pressure at idle and when running the machine (while lagging or not), it's a constant 25 psi. So I'm assuming fuel pump is fine. The three cylinders are at about 115-120 in compression each, supposedly this is an engine that's got less than 20 hours, about 90 on the machine itself. Previous owner let the machine sit for about 2 years without running.

    Any ideas, need help, running out of ideas here?? I feel like I'm missing something simple here.


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
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    Welcome

    Has this engine ever run reliably for you since you got it?

    Do you know if the machine has ever been reliable since the engine swap?

    Have you checked the sensor connections and sensor ohms?

    There is an air temp sensor installed into the bottom of the flame arrestor base. Hard to see under there, you may need to unbolt the flame arrestor bottom to get at the sensor contacts.

    Also check the ohms of the CPS sensor coil, which is installed at the top of the flywheel housing. Should be under 200 ohms, and typically is around 140 ohms.

    Since the engine has been removed, it is possible that you are chasing a loose connection in the wiring, or incorrect re-installation of something. Look for any signs of pinched or cut wires.

    Did you try gently squeezing the TPS connector's metal sockets (there are three), so they more tightly grip the metal pins of the TPS connector?

  3. #3
    pb0000's Avatar
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    K447,

    Thanks for the detailed troubleshooting. In response to your questions...

    The ski is running the same since I purchased it a few weeks ago, lagging about half the time when I attempt to go WOT. It'll sit there for minutes not accelerating, then on occasion, it'll come to life and accelerate just fine.

    The previous owner told me it was running fine (although it had been almost two years since it was used). I talked to him recently to confirm, and he said he noticed something similar for a very brief time after the rebulid, but it ran alomst 20 hours on the new engine without a problem after.

    My CPS seems to be fine, it read 120 Ohms. My air temperature sensor is reading 750 Ohms which is below the 1000 Ohm spec considerably. I'll replace this, but I'm not sure this is the problem. Don't see any crushed wires anywhere. I'll cinch down the TPS metal sockets, I already cleaned them really good. When I get the air sensor I'll take another ride to check out if there is improvement.

    Any other ideas? Much appreciated. Also, can you have error codes available even if there is no service light?

    - pb0000

  4. #4
    pb0000's Avatar
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    CORRECTION....OOPS

    My multimeter needed adjustment. 145 ohms on CPS, 1 kOhm on air temperature sensor, which is right on where it should be. Not going to replace air sensor. I did notice my plug wires are out of spec and different from one another, going to replace those.

  5. #5
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by pb0000 View Post
    ...can you have error codes available even if there is no service light?...
    The red warning lamp will not stay lit, unless there is a problem happening 'right now' with the engine.

    Sometimes the red lamp comes on for a very short time, and you might not notice it when you are riding.

    You can read the codes using a simple LED tester. Look here;
    How to read Polaris Ficht EMM trouble codes without special software or a computer

    The EMM will store codes until they are cleared.

    When reading codes with the LED, you will not know how old the codes may be. You can clear the codes after reading and recording them, then run the engine and see if any new codes are stored.

  6. #6
    pb0000's Avatar
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    Latest...

    Still having the same issue with this MSX-140. I've now read the error codes, got 11 which means no error at all.

    I've also changed out the spark plug wires. No change.

    Probably going to bring this in to a "professional", can't find issue, at this point I'm thinking fuel injectors but who knows?

    - Paul

  7. #7
    pb0000's Avatar
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    voltage at injector

    Decided to check the voltage going to the fuel injectors. Getting 42 volts when running, and it slowly bleeds down after stopping motor. Apparantly capacitor is bleeding down correctly. Is 42 volts OK when running? Spec from manual says MUST be 44-45...

  8. #8
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by pb0000 View Post
    Decided to check the voltage going to the fuel injectors. Getting 42 volts when running, and it slowly bleeds down after stopping motor. Apparently capacitor is bleeding down correctly.

    Is 42 volts OK when running? Spec from manual says MUST be 44-45...
    Was that voltage measured at idle, or close to idle?

    If measured near idle, then 42 volts sounds fine. As the RPM rises, the voltage should level out at close to 45 volts.

    ...it idles fine, but when I try to accelerate to WOT about half the time it just lags permanently at close to idle (<10mph). On occasion, it'll just work fine and speed up like normal like it should....
    The fact that it runs OK sometimes, and not at other times, implies an intermittent problem. If there is an electrical connection somewhere that is just hanging on, and sometimes it is contacting, and sometimes not, that would match the symptoms you have described.

    An intermittent electrical problem can be a challenge to find. It may take a lot of poking around and digging before you find it. Along the way, you find several things that look suspicious.

    Did you tighten the three metal TPS contacts inside the harness connector?
    Next would be to remove each TPS harness pin, and check for poor contact inside the wire, near the TPS connector.

    Next, I would then concentrate on the 12 and 8 pin connections to the EMM. Pull each pin out, and examine it for possible poor contact, or broken copper strands inside the insulation.

    Examine the EMM contacts for corrosion or dielectric grease. You do NOT want any grease on the actual metal pins, as the grease is an electrical insulator.

    While you have each contact in your hand, connect your ohm meter to the other end of that connection, and to the exposed terminal, and flex the wire near the contact. If the ohm reading jumps around, that contact is a suspect. Focus mostly on the 12-pin connector for this, after the TPS has been checked.

    Do not loose track of which contacts go into which holes on the connector

    Another test approach is to strap the ski firmly down to the trailer front and rear, then back it into the water until the jet pump intake is submerged.

    Now you can run it with the seat off, and even open up the throttle. Since it is in the water, you can run it like this as long as you need to find the problem.

  9. #9
    pb0000's Avatar
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    Finally fixed

    Finally fixed... I brought into the shop for repairs once I realized it was probably the computer (EMM). Shop confirmed it was bad computer. Sent EMM in, could not be repaired. After long search, and one nearly fraudulent purchase, finally found EMM. (Guy sold me an EMM and never sent it, Paypal returned my money thankfully.) Now installed and runs like a top. Had it running in the water properly for the first time since I bought it almost a year ago.

    Thanks for help, I wanted to add this note so the thread has a conclusion.

    - Paul

  10. #10
    Click avatar for tech links/info, donation request K447's Avatar
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    Glad to hear it is now working properly

    Did you buy just the EMM, or also the matching fuel injectors?

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