Thread: Fuel Injector Question
10-04-2006, 07:52 PM #1
Fuel Injector Question
Yes, this is my week of questions. Does anyone know what the butterfly's do on a Fuel Injected 1200? If it was carburated they would be the choke. No problem, just wanting to understand how this thing runs a little more. I have worked on snow mobiles engines before but I have never worked on anything with Reeds or Fuel injected.
10-05-2006, 08:45 AM #2
The injected engines only need the butterflies to smoothen idle .After that because of the direct injection used .The amount of fuel injected determines rpm .If you want to check what I am saying remove tps and open butterflies up and the engine will only increase in speed if you operate /adjust tps reading to engine .Much the same as a mechanically governed diesel engine
10-05-2006, 01:07 PM #3
- Join Date
- Oct 2006
- Beaver Falls, PA
HMMMM I thought the butterflies were to make the engine lean to the air fuel mixture and the tps on the end was to tell the injector how much fuel is needed in relation to the butterflys opening. Am i missing something here? Because when I took the tps off an left the butterfies closed and rotated the tps it fuel fowled out my plugs. Bernie how does your test go again? Vegas wanted to know what the butterflies are for?
10-05-2006, 01:49 PM #4
- Join Date
- Apr 2006
- panama city beach 'fl
Throttlebodys feed air in preposition to fuel allowed to flow thru injectors for given rpm and load, tps is feedback of butterfly opening
So the emm is looking at
How much air is allowed
The emm then tells injectors how much fuel to give
Or itís magic, donít ask (jk)
10-05-2006, 01:51 PM #5
I'm lost???? Something has to let air into the motor... usually it's the throttle plate position...
10-07-2006, 07:02 PM #6
Seems odd doesn't it. But the fuel determines what revs it does .These engines are so finely tuned when it comes to fuel /air ratios that amount of fuel delivered is so precise that it controls the Rpm's .Think of a deisel engine Say 6.5 Turbo Chev .Fly by wire throttle control .No butterfly restricting airflow here, just precise fuel metering .The rest looks after itself
10-07-2006, 08:01 PM #7
That is pretty cool. So tell me this, my butterflies don't open 100% at full throttle. They are still just a little bit closed. I am guess that this really doesn't make a difference, or does it?
The only thing I don't like about this fuel injected motor is I can't controle any of the settings. I can't make it run richer or leaner, or even adjust the timeing in any way. Other than that I REALLY like this boat. Especially now with the new reeds.... awesome..
10-08-2006, 05:55 AM #8
If you have one that is running well ,leave it alone and thank your lucky stars .If you want more grunt ,By a Matrix or save up for 250 hp machine
10-08-2006, 01:29 PM #9
LOL.... thanks for the advise Bernie... i think i will do just that. I have been working on this thing for a long time and it is finally running great. i think i will just leave it the way it is now. I have an old 650sl with a dead engine i can work on over the winter.
Thanks again for all your help. One of these days when i finally make a trip down under you will have to show me some great places to ride..
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