2 Cycle Fuel Injection

[levittownnick]

What is wrong with swapping fuel injectors from one cyllinder to annother on the same engine? How is this different than installing a new injector? (The service manual cautions to return it to the same location where it was originally installed.)

 

[JB]

Re: 2 Cycle Fuel Injection

What engine are you talking about, Nick, and why here?<br /><br />Moving to Outboard Non-repair.

 

[levittownnick]

Re: 2 Cycle Fuel Injection

Good Afternoon JB,<br />The question is a general F.I. question and it relates to a post (that was not resolved) in the PWC section concerning a 2003 Kawasaki 1100 stx di.<br />Since the question is general in nature about Fuel Injection of 2 cycle gasoline engines, I elected to tap the knowledge of the group reading the general discussions. Since the post about PWC is not mine, I did not wish to step on his post.<br />I am still very interested in learning the answer to my question.

 

[jegervais]

Re: 2 Cycle Fuel Injection

On certain Direct Injection engines, the fuel injectors are "flow-compensated".<br /><br />For example, in order for a DI engine to run properly at all rpm, the injector must deliver a nominal amount of fuel over the rpm range. Due to manufacturing variances or assembly tolerances, one injector may flow lean, while another may flow rich. <br /><br />In order to compensate for this (and not throw bunches of injectors in the scrap heap), the manufacture will use software to control the pulse-width ("on" time of the injector) to make it flow correctly.<br /><br />So it you put a lean flowing injector in a cylinder that's compensated for a rich flowing injector, it will deliver even less fuel and destroy the cylinder (leaner = hotter).<br /><br />Make sense?<br /><br />-John

 

[levittownnick]

Re: 2 Cycle Fuel Injection

I thought this topic had died.<br />Thanks for the response John. It does make sense. Is the compensation tecnique do-able for non-professionals or is there a expensive set-up required?

 

[jegervais]

Re: 2 Cycle Fuel Injection

Not sure what you mean by do-able for the non-professional...<br /><br />For those of us who do this for a living, when we install a new injector, it comes with a software disk which has the flow coeficients for the new injector on it. <br /><br />We use the diagnostic software program to make the required software change. What the program won't do, is swap the data from one cylinder to another - Hence the "Don't do that" warning.<br /><br />For Evinrude outboards, the expense is in the cost of the lap-top, a comm cable ($57) and software ($200) and of course the formal training...<br /><br />-John

 

[seahorse5]

Re: 2 Cycle Fuel Injection

Originally posted by John from Illinois:<br /> Not sure what you mean by do-able for the non-professional.... <br /><br />We use the diagnostic software program to make the required software change. What the program won't do, is swap the data from one cylinder to another - Hence the "Don't do that" warning.<br /><br />For Evinrude outboards, the expense is in the cost of the lap-top, a comm cable ($57) and software ($200) and of course the formal training...<br /><br />-John

Additional expenses are required for the factory service manual and the software instructional booklet.

 

[levittownnick]

Re: 2 Cycle Fuel Injection

I'm beginning to get the picture. It can be done but I'll go broke doing it.<br />Thanks for the information.