Fuel injector cleaning / flow check
aero3113
Member Posts: 9,071 ✭✭✭✭✭
Just curious if anyone has removed their injectors and sent them out to be cleaned and flow checked? It seems like it could be a good preventative maintenance item. I saw some pricing online for about $12-$15 per injector, including all new seals.
2008 330EC
Comments
https://www.boatus.com/magazine/2017/december/cleaning-marine-fuel-injectors.asp
2018 Cherokee 39RL Land Yacht (Sorry...)
Remove each injector one at a time.
Verify what volt they operate. Some Hondas are 1.5 v and volvo was 12v. They don't have constant power they have on/off pulses of power.
I first cleaned the body of the injectors and the fuel inlet screen. Google a break down of your injector as not all come apart the same.
I attached a few inches of hose to the inlet of injector and out gently in vice.
I then fill the clear hose with carb cleaned. I then apply power to the injector. Once power is applied i push about 40 psi of air through the injector looking for a fine even mist. This isnt a precise cleaning method a pro injector shop would use but it has worked for me over the years.
Repeat until you get a good even flow from each injector.
PC BYC, Holland, MI
let's say you have a set of ford racing four hole sprayers designed for 39# pressure and 'delivering' 24#... that is around 252ccpm. fuel is atomized into a fine mist, which means you can retard your fuel sync a degree or two and miss the design of 'pencil' spraying the back of a hot valve to assist in the atomization... slightly increases throttle response and bumps economy- but that same injector balanced perfectly at 39#'s bumped to 44#'s or dropped to 36#'s? no bueno... any advantage is lost.
atop that, fuel pressure may be balls on, but one injector has a larger orifice due to 'cleaning'- the fuel pressure may be right and tight on closed injectors (i think merc's are either 34# or 36#'s) when the gate opens on the reamed injector the pressure drops and you'll get a contribution imbalance that is a MONSTER to track down.
it isn't that expensive... get it professionally done... ALL that said, it's highly unlikely anything is wrong with your injectors unless you are running questionable fuel... which is more likely in a boat than a car, but still just not that likely. if you KNOW your injectors are good and well balanced for flow, you can again retard the fuel sync ever so slightly- like 3* max- and you'll be impressed at the perceived difference, most noticeable off the line or out of the hole. all you'll really have done is kick things off a little lower than usual, but... that's where we need it most.
Also explain the difference if any with diesel injectors.
Thanks
diesel injectors are a completely different animal. they 'were' mechanical which is to say without electronic controls.. i think your yanmars were equipped like that. they went through an evolution of HEUI types- where fuel is delivered to them and the injector itself (using a piston) created the pressure required... then, and this is pretty slick, they moved toward piezoelectric controlled injectors... the central fuel pump provides pressure to the fuel rail (common rail, much like gassers) and at silly high pressures- and the injector works with the same concept of a gasser as a 'gate keeper'. the actuation, though, is where the magic is- they have a tiny lever in them and a stack of material below them with the piezolectric charge- when the charge snaps the lever opens the gates of the injector and relies on 'duty cycle' to allow whatever volume of fuel past it. the difference between piezoelectric of diesels and solenoid of gassers is reaction time... with the piezoelectric they are FAST... like, some diesels can have as many as seven injection events on a single cycle, chasing the piston all the way to the bottom of the stroke increasing torque tremendously. most diesel injectors rely on the diesel itself for cooling and lubrication- so the ULSD diesel is tough on them without lubricity added to it... and, those tiny gates rely on a 'padding' of fluid (diesel) to keep hard surfaces from colliding- running them dry can wreck them quickly.
i've always had good resutls from FiveOh and with Bruce. the guy knows his business thoroughly. off the top of his head he can offer which injectors at what pressures can be interchanged, or what common cam swap (increasing flow) on what engine requires what injectors.... he prefers to speak in cc's and pressure which is more precise than the 'pounds' and emerging industry standard for rating of 43# of rail pressure. he can tell you which patterns are better for which engine and mods... he really knows what he's talking about.
with the HEUI style, people put 'tips' on them to increase delivery. clumsy, but it worked. when the common rail high pressure fuel systems arrived, and the piezoelectric injectors were introduced- the magic really started.. instead of opening the pulse width (duty cycle; amount of time injector is open) wider and seeing a lot of un-burnt fuel (black smoke), you started seeing additional injection events- spitting into cylinder prior to traditional events- and then literally adding to the fire at TDC, and then 'chasing' the piston south in a post power stroke injection event.. varying volumes of delivery on each event (programming different pulse widths for each event) and kaboom- an engine delivered from the factory delivering 325hp and 600#tq would now, and easily, produce 500hp and north of 800#tq- simply with an alternate tune on the PCM.
chips are a thing of the past, too... dangerous with the more sophisticated fuel systems of today's trucks.
of course to get the most, it's about balance. without the air passing through that engine to match the increased fuel, you're generating ridiculous amounts of heat. 'clearer' exhaust systems and heavier turbos, and freakin beach ball size filters matching larger air box's, and same engine with same tune now near 700hp likely, and pushing 1k#tq.
2018 Cherokee 39RL Land Yacht (Sorry...)
I ran some STP through and now my starboard engine is burning more fuel than port. Figure I have a bunked up injector.
https://www.westmarine.com/buy/quicksilver--quickleen-engine-fuel-system-cleaner--12419594?gclid=CjwKCAjw5s6WBhA4EiwACGncZRkDWa52RFiOrgmEaBfSKPao_klieYdqVqENyrQJSWkBiOP7Zz7KvRoCkaEQAvD_BwE
In the meantime I am trying to track down the MAP sensor to swap between engines. Any idea where it is??
Edit: found it.