Half open Injector?

[Marc Alexander]

Are you saying that you see a good signal into the MC3484S4-2, and there is
no good injection pulse coming out of the MC3484 ?
If so, then they may be overheating. The MC3484 has a thermal shut down 
feature, are they adequately heat-sunk, and not too hot?
Do you have a ~470R resistor between the MC3484 power pin, and +12V ?
Is the MC3484 overvoltage protection pin grounded, or below trip level?
What resistance are your injectors?
Is the MC3484 input triger signal above the threshold for activation?

If you are going below around 1mS of injector time, the injector will not 
be opening properly either. This means you generally have to go to 
smaller injectors, or a different injection sequencing method.

Good luck!

Marc
 
>I am dealing with a custom EFI box for our FSAE team and we are having a
>problem with fuel delivery.  The symptoms have included no injection,
>injection through 2 out of 4 hoses, and then now injection in all
>cylinders, but extrememly low engine power output.  Under all of theses
>situations, the microController thinks it is injecting, and there is a
>control signal coming out of it to the driver chip.  The driver chip is a
>MC2484s4-2 and the cpi is I believe a delco product, although I don't know
>exactly which part it is or what it is off of.  Oh, and we have swapped
>injectors and injector hoses and fuel pumps and lines and everything
>possible and all this did was change the way the problem presents itself,
>not eliminate it.
>
>I am wondering if maybe the injector is not opening fully.  Has anyone had
>this problem before?
>
>Thanks in advance,
>--dan elsberg
>
>--
>Dan Elsberg                                             dhe1 at cornell.edu
>Cornell University, Engineering Physics                   (607) 256-5282
>
>
 
_Marc Alexander m.alexander at sungear.mame.mu.oz.au ph 93448105  fax 93482108_
_CMC Mechanical + Manufacturing Eng. Dept. Melbourne University,  Australia_
_______To stay young requires unceasing cultivation of the ability to_______
_______unlearn old falsehoods.__________Robert A. Heinlein__________________