03 MSX 140 fuel injector question

[dcarstens73]

I know this is probably a rarity, but I live in Alaska and have owned a PWC for 12 years now...take it out all the time with living on a lake, and no, the lake is not very warm. I think I have my issue narrowed down to the middle fuel injector and these things are difficult to find. I need to order it online, but before I do does anyone know if the replacement injector needs to be a middle one as well? As I read a couple of posts, people talked about calibrating it to the machine, which I'm lost on as well. If anyone has any advice/help/direction, I would appreciate it. Thanks for reading.
dc

[K447]

Welcome

Before condemning the middle fuel injector, can you tell us how you diagnosed the problem? Ficht Fuel injectors can fail but it is rare. Much more common is failure inside the EMM module that controls the fuel injectors.

Have you checked the fuel pressure?

If you have not done so already, click on my signature links. Lots of useful info in there.

[dcarstens73]

At first I thought (hoped) it was the spark plug wire, but quickly eliminated that after I felt the voltage going through it (literally). When I had it running, I took off the middle spark plug wire and there was no change in engine performance. I replaced that wire and did the same for the front and rear wires with the engine starting and sputtering out, no performance at all. Basically it all started when I refueled about a week ago and the ski had absolutely no torque or power when I came back out; topped out at about 25 after a bit. It got gradually better, but topped out at about 35 with the ski hesitating and "missing", especially when i gave it more throttle. I even drained out all the fuel, put fresh fuel in and tried a fuel injector cleaner to boot. I'm not exactly sure how to check the pressure or the other EMM modules...I guess I'm more of a big picture type guy...

[martincom]

Fuel pressure regulator issues are just about a given on any FICHT direct injection Polaris. If it hasn't failed yet, it will. The symptoms you reported are indicative of that failure. I purchased two non-running Virage Is a few weeks ago and the pressure regulator was laying in the bottom of the fuel canisters in both of them when I pulled them out on Saturday. One now runs, the other had a malfunctioning CPU board (probably capacitor C89 from the symptoms) in the EMM---which is another failure on FICHT machines which is just about a given.

Connect a fuel pressure gauge to the Schrader valve (tire valve) just in front of the injectors, in the fuel return line. While cranking the engine or with it running, you should see 25 psi. If not, crimp the return closed with a needle nose pliers, on the fuel tank side of the Schrader valve, and if the pressure jumps up to 30 psi or thereabouts---your pressure regulator has fallen off inside the fuel tank. See this post for details on how to repair so it doesn't fail in the same manner again:

http://www.greenhulk.net/showthread.php?t=77110

The MSX140s are known for eating center cylinder pistons when this occurs due to the lean mixture caused by low fuel pressure and it is typically the hot cylinder, being in the middle. You may want to check the compression on the middle cylinder to determine if this has occurred--since it doesn't make much difference when you pull the spark plug wire for the center cylinder. If you don't have a compression gauge, just place your thumb or large finger over the top of the spark plug hole while cranking the engine. If you can't hold it there, it is good. If you can and feel little or no pressure, you burned a hole through a piston.

Regardless, you definitely want to apply the fuel pressure regulator fix whether or not it is your problem in this instance.

[dcarstens73]

OK...I checked the fuel pressure and it is good. I also used a mirror set up to check to see if the top of the fuel pump looks like it does in the images from the link you provided of the correct set up and it does. I also checked the compression of the middle cylinder and you can definitely feel the pressure coming out. Having done those checks, it seems like it boils down to the injector...unless of course there is another component that I'm missing. If it is the injector, do I need to find another center cylinder injector to replace it with? Thanks for all the tips, I definitely know my machine a little bit better now.
dc

[K447]

... it seems like it boils down to the injector...unless of course there is another component that I'm missing...

... Ficht Fuel injectors can fail but it is rare.

Much more common is failure inside the EMM module that controls the fuel injectors.

...

If you have not done so already, click on my signature links. Lots of useful info in there.

These Ficht engines are completely different from a typical car engine with fuel injection. Each Ficht fuel injector is actually an electrically powered high pressure fuel pump.

My expectation is the large EMM computer that controls both the fuel injectors and the ignition has developed a fault. It could be a spark problem or a fuel delivery problem for that cylinder. Each cylinder has separate electronics within the EMM.

When the engine is running, is there a Check Engine message on the dash display?

[dcarstens73]

No, I do not get a check engine light/message. Is there a way to check if there is a bad component in the EMM?

[martincom]

How, specifically, did you check the fuel pressure and what was it?

I've had a defective EMM report way out of whack parameters, such as engine timing, when they have/are failing. This requires the diagnostic software. The best way to check an EMM is to swap it out with a known good unit.

While it is the consensus of most that is highly unlikely you have a defective injector, it seems you are stuck on that conclusion. You can swap the injector with that of another cylinder for brief testing purposes. Be sure to label each injector's cylinder location before doing so to make sure you return them to their original positions. Also, exercise caution when extracting the plastic nipples so you don't crack them. Also, the injector mounting bolts are stainless steel and an issue with stainless bolts is thread galling. Hopefully, they'll come out without issue (I had one gall and stripped the threads in the head on Saturday---a helicoil repair). I always coat the threads of the injector bolts with "Anti-Seize" compound when re-installing. It is available at automotive parts store and online.


To reduce production costs and allow for more latitude with production tolerances, these injectors are individually measured and four coefficients are established as a measurement of their individual characteristics. These coefficients and the injector's S/N are stored within the QR code stamped on both sides of each injector. If you have a QR code reader app for your smart phone, you can read this information from each injector. These coefficients and S/N numbers are programmed into the EMM so it can utilize this information to custom tailor the control of fuel delivery based on these coefficients. This is why you can't simply swap injectors around or replace them with another used unit. New replacement injectors included a disc that contained these coefficients in a format that could be imported into the diagnostic software (Digital Wrench or DW) and then programmed into the EMM. Sadly, the diagnostic software does not include the functionality to allow for editing of the coefficients. So, installing an injector whose coefficients are not programmed into the EMM will result in a mismatch that will, in turn, result in a lean or rich mixture and to an unknown degree. Thus, why you want to keep any testing of a mismatched injector to a minimum.

In a nut shell, you can't simply replace one injector with an ebay find. To replace a defective injector with an ebay find, you must replace all three injectors and the matching EMM. Without the diagnostic software to verify they are truly a matched set, you are at the mercy of the integrity of the seller and ebay is full of sellers with zero integrity and ethics.

[Mikey N.C.]

I don't see very many of them, but do Johnson/Evinrude exactly the same EMM, it has the orange wires going to the coils, for spark, just like outboards. Yes a dva adapter on voltmeter, spike
Orange wires to each coil, you should have at least 140 volts , if not it's EMM.

[Myself]

Holy thread revival Batman!!!

[HiPeRcO]