S4 TII resistor pack removal question
05-23-05, 09:59 PM
#5
Originally Posted by jkrueger
If you have the low resistant injectors, you may want to the resitor pack in place otherwise you may burn up your injectors.
the splicing/soldering worked...she fired up first try...
but...i'm getting a really shitty idle. worse than before pulling the resistor pack. I checked the TPS and it's sitting pretty. I'm thinking my LIM gasket may be fried...
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05-24-05, 01:54 AM
#8
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It's 12V from the main relay, which gets divided via resistors to the four wires that go to the injectors.
Last edited by NZConvertible; 05-24-05 at 01:58 AM.
05-24-05, 05:32 AM
#9
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Just because you have high impedence injectors doesn't mean your ECU will work well with them. Keep in mind that the impedance on HI injectors is anywhere from 13-15 ohms where as in the LI setup the resistor for each injectors plus the injectors impedance combined is roughly 8.5 -10 ohms. We have tested both high and low impedance injectors on a stock 88 NA ecu with and without the resistor pack and what we found is the HIs didn't even open enough for the car to start and the LIs only dump a little more fuel without the resistor pack but as jkreuger said the higher voltage supplied will fry low impedance injectors. And yes the black/yellow that you think is ground is actually hot when key is on and the ecu is just supplying a ground on/off for the injectors(prevents circuit lag).
05-24-05, 06:58 AM
#10
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Originally Posted by ironpanther
Just because you have high impedence injectors doesn't mean your ECU will work well with them. Keep in mind that the impedance on HI injectors is anywhere from 13-15 ohms where as in the LI setup the resistor for each injectors plus the injectors impedance combined is roughly 8.5 -10 ohms. We have tested both high and low impedance injectors on a stock 88 NA ecu with and without the resistor pack and what we found is the HIs didn't even open enough for the car to start and the LIs only dump a little more fuel without the resistor pack but as jkreuger said the higher voltage supplied will fry low impedance injectors. And yes the black/yellow that you think is ground is actually hot when key is on and the ecu is just supplying a ground on/off for the injectors(prevents circuit lag).
-Ted
05-24-05, 04:49 PM
#11
Originally Posted by ironpanther
Just because you have high impedence injectors doesn't mean your ECU will work well with them. Keep in mind that the impedance on HI injectors is anywhere from 13-15 ohms where as in the LI setup the resistor for each injectors plus the injectors impedance combined is roughly 8.5 -10 ohms. We have tested both high and low impedance injectors on a stock 88 NA ecu with and without the resistor pack and what we found is the HIs didn't even open enough for the car to start and the LIs only dump a little more fuel without the resistor pack but as jkreuger said the higher voltage supplied will fry low impedance injectors. And yes the black/yellow that you think is ground is actually hot when key is on and the ecu is just supplying a ground on/off for the injectors(prevents circuit lag).
Ok....
First off, the car actually fires up better than with the resistor pack. I know that the wire that I previously thought was a ground is actually not one. Hailers kinda opened my eyes with his statement about none of the wires being grounds.
Second...this is on an 87 TII. Different injectors than an NA if I remember correctly.
Third, there is no black/yellow wire. It's black with a shield over it. In fact, all of them are black. The four that are unshielded have white diamonds printed on them....Are you sure you're actually looking at a resistor pack and not the other (fuel pump?) relay located above it?
Anyway. The issue at hand now is not with the resistor pack. I seem to have a obscenely large vaccum leak somewhere on the intake. Probably the LIM gasket seeing as how I replaced all other gaskets which were fried but not that one...
So, since I pulled the resistor pack and I'm getting a lot more air sucked into the engine via the leak, i'm leaning out badly.... I'm going to put the resistor pack back on and chance running rich until I get time to pull the manifolds off and fix gaskets/vaccum leaks as needed....
05-24-05, 05:58 PM
#14
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Originally Posted by ironpanther
Keep in mind that the impedance on HI injectors is anywhere from 13-15 ohms where as in the LI setup the resistor for each injectors plus the injectors impedance combined is roughly 8.5 -10 ohms.
Impedance in this case is resistance to current flow due to the electro-magnetic field set up by the injector coil. It is NOT 13 ohms with the injector powered by our cars' 12vdc system, but does read the 13 ohms when powered by our puny meters...
As long as the total circuit impedance is about the same with the injectors energized, the ECU won't care...
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