2004 MSX140 only has spark on 1 coil

[jjmyzrider]

Hello....first time posting here but have lurked for a few years.

I purchased a 2004 MSX140 a couple of weeks ago. Original owner stated he was running the ski on the lake when it shut down on him. He towed it to shore loaded it up and took it home. He was able to get it to run a bit, it was really rough.
I went to look at buying it. It fired a bit, and with the throttle open while cranking was able to start and Rev up, but I could tell it wasn't quite right. I purchased it and a single trailer and drove them 200 miles home. When I tried to start it at my house it would crank but not fire.

He said he was messing with the 8 pin connector on the computer, so that is where I started.
- I see white red pin on connector side has a brown ring suggesting it has gotten hot.
- cleaned computer connections with electric contact cleaner.
- tested for spark, only PTO side has spark, I used all 3 plugs and all 3 wires in all 3 locations and only PTO has spark with all combinations.
- unplugged tps, won't start
- CPS reads 146 ohms
- crank voltage to injectors is 28v PTO, 28v Mid, 27v Mag
- crank voltage of 10.8v, after charging for a bit 11v
- if I ground fuel pump I hear it run. I hear it run for 1 or 2 seconds after crank cycle ends.
- display wakes up after cranking, displaying mph and time.
- once I had a check engine result on the display, but I think I didn't have the 8pin connection in all the way. Check engine is currently not displayed.

- I didn't check fuel pressure, I need to buy a tester.
- didn't think it would be the regulator as it has spark to 1
- might just be coils, but for them to go bad at same time and fact PO had it running seems unlikely.

- ? Is there a test for the signal wire to the coil
- ? Any other ideas

Probably need to send the computer in for a test. I just want to test what I can on my end before I send that out to be tested.

Thank you in advance, this sit is very helpful in the way it was intended to be, unlike what snowest has become. Thanks again!

[K447]

Welcome.

Bookmark this web site. Lots of useful info.

http://polarispwcknowledge.shorturl.com/first-things-to-do

28 volts on white/red wire suggests the EMM is not attempting to operate all the Ficht fuel injectors. Note that unplugging any of the white/red wires can change the measured voltage. Our injector voltage diagnostics expect all injectors are plugged in.

Ficht fuel injectors are actually electrically powered pulsed high pressure fuel pumps. Each injector requires significant electrical power to operate. When all three injectors are operating the expected voltage on white/red wire is around 21-23 volts DC.

The burned white/red wire on the 8-pin plug needs to be corrected. The white/red wires from the EMM deliver the 'injector voltage' to the injectors and back to the ignition control half of the EMM. There is no internal link between the EMM power sections and the EMM engine control section. The EMM power section receives AC energy from the Ficht stator inside the flywheel and generates injector voltage.

I would be suspecting that one or two of the injector driver circuits inside the EMM has failed.

There are some additional diagnostics that can be done.
Do you have access to another Ficht three cylinder PWC?

The easiest path is to remove the EMM and have it inspected by Lakeside Tech.

[HiPeRcO]

There is certain EMM failure mode that causes the EMM to reset every time it tries to fire an ignition coil. So I suspect that this is what it happening, since as K447 noted the injector volts when cranking are higher than to be expected. In this scenario, it may not even be firing the PTO injector before the EMM is reset and starts again to try to synchronize with the cranking engine (thus not firing the other two injectors either). I (via Lakeside Tech) can test the EMM.

[jjmyzrider]

Thank you for the fast replies.
I will retest those voltages at the injectors with a better meter and verify those values are accurate.

If so, I will send you my computer and have it tested. I will order a new connector and get the pins replaced and repaired.

I do not have access to another MSX140. I only have a SLT750, as far as Polaris machines.

Thanks again!

[jjmyzrider]

Does the coil signal come from the stator or the MME? I understand that the voltage is high for the injectors, how does that translate into producing spark at 1 coil but not the other 2?

[K447]

Does the coil signal come from the stator or the EMM?

I understand that the voltage is high for the injectors, how does that translate into producing spark at 1 coil but not the other 2?

On a Ficht engine the stator only supplies AC energy to the EMM. The EMM converts that to DC power and then uses it to run everything on the engine.

The EMM runs the entire ignition system, and the fuel injection system. There are sensors on the engine that feed into the EMM for flywheel timing, exhaust water jacket and air intake temperature.

Inside the Ficht EMM are three separate sections, one for each cylinder. Each section has a driver for the fuel injector and a driver for the ignition coil. There are also some shared circuits.

The EMM also switches the fuel pump on and off, but the power for the fuel pump comes from the 12 volt battery.

The EMM power section also provides 12 volt battery charging through two other pins on that same 8-pin connector.


You can do some diagnostics by connecting the working ignition coil to each of the other primary ignition coil wires. If the coil still produces spark then those EMM ignition circuits are probably good. If the other coils do not produce spark but the original coil still does then the other coils have failed. Ignition coil failure can happen but that is not a common failure mode.

EMM failure is more likely.

[jjmyzrider]

I re-tested those injector voltages, yeah confirmed to be 28v.
I did not take the time to move coils around, I assumed that the computer would need repaired either way. So k will ship the computer off and have it tested.

Thanks.

[jjmyzrider]

I finally found some time to get back to looking at this Polaris, and made some progress.

1) sent the EMM to Lakeside and it tested good.
2) was able to verify 22psi of fuel pressure during cranking.
3) all 3 coils spark when using the known good signal wire
4) somewhat tested stator I can't find my digital meter.
Analog not accurate enough to test ohms but was able to test voltages
1& 12 = 7.5v open to ground
2 & 11 = 8v. open to ground
3 & 10 = 5v. open to ground
4 & 9 = 5v. open to ground
5 & 8 = 5v. 3500 OHMS to ground

Removed crank sensor and retested 140ohms on Analog tester
Re installed crank sensor. Hit start button and it fires and runs for 1 or 2 seconds.

So my thoughts are
bad crank sensor even though ohm reading is in range.
bad stator and/ or flywheel
bad ground........did apply second ground strap. No change. Where does the factory ground attach? Under the engine somewhere?

Any ideas? Is the coil attached to the engine cover, or behind the flywheel?

Thanks for helping and the advice.

[K447]

..L
1) sent the EMM to Lakeside and it tested good.
-
4) somewhat tested stator I can't find my digital meter.
Analog not accurate enough to test ohms but was able to test voltages
1& 12 = 7.5v open to ground
2 & 11 = 8v. open to ground
3 & 10 = 5v. open to ground
4 & 9 = 5v. open to ground
5 & 8 = 5v. 3500 OHMS to ground

-
bad stator and/ or flywheel.

Sounds like something has happened to the stator, partially shorting one of the stator coils to engine ground. The EMM power section will not like that.

The Ficht stator is mounted behind the flywheel. On MSX 140 the factory flywheel is twelve magnet type, which usually does not give much trouble. The six magnet flywheels used on red Ficht engines were known to sometimes have magnets get loose and damage the stator.

The flywheel must be removed to get at the Ficht stator.

[K447]

There are a couple of places where the wire harness connects to the engine for 'ground'.

Going from memory, one wire harness to engine metal connection is near the ignition coil set.

[jjmyzrider]

There is a ground from the aluminum coil bracket to the engine block. I don't know where the battery ground goes to.

Is the best way to remove the flywheel and stator removing the engine?

I have read some about the exhaust temp sensor being bad and not allowing the engine to start. How do I rule out that, any other simple checks before I dive into the stator? I think my 3500 ohms to ground is a for sure stator problem.

[Beernutz]

...Is the best way to remove the flywheel and stator removing the engine?...

While I have no first hand experience in stator replacement in an MSX, From what I have read and can see looking at my own skis, is yes, you have to remove the engine to service the stator and flywheel. Plus, while the engine is out, it will be much easier to do the mandatory fuel pressure regulator repair, as well as give you an opportunity to deep clean the inside of the hull.

[martincom]

There is a ground from the aluminum coil bracket to the engine block. I don't know where the battery ground goes to.

Is the best way to remove the flywheel and stator removing the engine?

I have read some about the exhaust temp sensor being bad and not allowing the engine to start. How do I rule out that, any other simple checks before I dive into the stator? I think my 3500 ohms to ground is a for sure stator problem.

The battery cable ground and the main harness ground attach to a engine block bolt at the rear left (port side) of the engine.

Attempting to re-install the flywheel with the engine in the hull is asking for trouble, in my opinion. Things are just too tight and hard to see. The risk of mis-aligning something or dropping a fastener into never-never land are very great. The magnets, in the flywheel, are very strong and will rip it out of your hand when attempting to line it up.

I don't believe a defective exhaust sensor will prevent it from starting. Regardless, it is easy to check with an ohm meter. The service manual has a chart to indicate what they should indicate per a given temperature.