|
|
|
|
|
|
|
#1
12-17-2007, 12:30 PM
|
|||
|
|||
Bosch Fuel Injector Polarity
I have searched around....
Does anyone know why Bosch Fuel Injectors are marked with a small + to show the positive side. Does it matter? If it does how would I check all is in order as I seem to have a DIY loom on my M119 engine. (500E) Engine Management is LH 5.01. Searching around I only found one clear statement and it said that as it's only simply coil polarity does not make any significant difference. Jim. 
|
|
#2
12-18-2007, 03:31 PM
|
|||
|
|||
|
That is a very interesting question. I can think of 2 guesses:
1) The injector has a built in flyback diode. (I am unaware that any do but I don't know) 2) The injector is more "sensitive" or faster with one polarity. Hopefully some smart person will chime in with the answer. You might try putting an ohm meter across the injector one way then the other and see if the readings are any different.
__________________
1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine) 1988 F150 144,000 miles (leaks all the colors of the rainbow) Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra
|
|
#3
12-18-2007, 05:16 PM
|
|||
|
|||
|
I'm not a smart person but I did read the "design and function" section on the service CD for my 95 E320. It contains the following note:
The positive and negative polarization at the fuel injection valves must not be mixed up. No further explanation is given. Service CD reference: Program\Engine\LHIS\07.4-0030.pdf J. M. van Swaay
|
|
#4
12-19-2007, 02:22 AM
|
|||
|
|||
|
Maybe the injector is grounded, ergo bingo, short circuit.
__________________
1991 300 SEL 218,000 Km "Xsbank's rules of mechanical intervention: Always go for the easiest solution first; 90% of what ails a gasoline engine is ignition; After that its all a WAG."
|
|
#5
07-18-2010, 08:57 AM
|
|||
|
|||
|
Quote:
|
|
#6
07-18-2010, 10:21 AM
|
|||
|
|||
|
Bosch EFI injectores are on/off solenoid valves. When you turn the key to position 2 power is provided continuously to all injectors on the + side. When the engine starts, the injectors are triggered on/off by grounding the - side in pulses. EFI injectors work at constant pressury via pulse width modulation. The ECU simply times longer or shorter pulses depending on the amount of fuel required. If the polarity is reversed, the injectors will not work. If there was something wrong with the harness the engine woudnt start.
This information is for megasquirt but it applies exactly the same way to any other EFI system. http://www.megamanual.com/v22manual/inj_ani.gif
__________________
CENSORED due to not family friendly words 
Last edited by tjts1; 07-18-2010 at 10:52 AM.
|
 |
| Bookmarks |
|
|
Hybrid Mode
