Chris2012 Posted November 2, 2013 Report Share Posted November 2, 2013 I popped both connectors, one on each side of the engine and measured. With 1 plugged in, the other read 2.6 ohms With each unplugged, both read 3.2 ohms. ??? (1992 3.1 mpfi Lumina) Quote Link to comment Share on other sites More sharing options...
19Cutlass94 Posted November 3, 2013 Report Share Posted November 3, 2013 Are you trying to measure the resistance of the injectors themselves? If so, just removed the UIM, remove the connector, and measure the injector. Should read about 12.5ohms. Quote Link to comment Share on other sites More sharing options...
Chris2012 Posted November 3, 2013 Author Report Share Posted November 3, 2013 Are you trying to measure the resistance of the injectors themselves? If so, just removed the UIM, remove the connector, and measure the injector. Should read about 12.5ohms. i'm trying to avoid removing the plenum at this time if at all possible. I had thought those connectors provided some means of determining if each bank is healthy? or not. from the wiring diagram I'm not even sure what these connectors represent. and it just occurred to me while I ohmed across the pins of the receptacle, which is what unplugs and is left dangling, maybe I should/should also have ohmed the plugs that sit in the recesses. Quote Link to comment Share on other sites More sharing options...
Chris2012 Posted November 3, 2013 Author Report Share Posted November 3, 2013 ok, 11.9 on the passenger side, 12 ohms on the driver side close enough. for those 2. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted November 3, 2013 Report Share Posted November 3, 2013 a bank of 3 injectors in parallel, to come up to 3.2 ohms would average just under 10 ohms each. kind of low, would imply that the injector coil in at least one of the injectors is shorting. Quote Link to comment Share on other sites More sharing options...
Chris2012 Posted November 3, 2013 Author Report Share Posted November 3, 2013 a bank of 3 injectors in parallel, to come up to 3.2 ohms would average just under 10 ohms each. kind of low, would imply that the injector coil in at least one of the injectors is shorting. if you can explain how I can disconnect the harness under the passenger side fusebox, I can with more certainty explain why there are no shorts. the numbers already agree with close certainty. for now just understand you do not get to ohm individual banks from those connectors on the sides of the plenum. got to go to bed. more tomorrow. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted November 3, 2013 Report Share Posted November 3, 2013 looks like on a 92, all injectors are fed through a single pin on the C102C connector. 90 and earlier are run through 2 seperate pins. i can never remember the breakpoints for that. since all 6 are being dealt with, that is near 19 ohms per injector. Quote Link to comment Share on other sites More sharing options...
Chris2012 Posted November 5, 2013 Author Report Share Posted November 5, 2013 Here and there I see people stating these injectors have power AND signal input. Is this true?? Up until now I thought they were just pulsed by the ecm to open and spray. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted November 5, 2013 Report Share Posted November 5, 2013 depends on your interpretation of them. they're given +12V through a fuse at all times the ignition is on, but their ground circuit is opened until the PCM commands them on. Quote Link to comment Share on other sites More sharing options...
Chris2012 Posted November 5, 2013 Author Report Share Posted November 5, 2013 when they're not spraying gasoline is there any voltage applied to them? Quote Link to comment Share on other sites More sharing options...
Chris2012 Posted November 5, 2013 Author Report Share Posted November 5, 2013 when they're not spraying gasoline is there any voltage applied to them? Ok, let me rephrase the question. When you pull the connector on either side of the plenum, is that injector totally isolated from any voltage connections. Are there any electrical connections at all to that injector once that plug is pulled. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted November 5, 2013 Report Share Posted November 5, 2013 injectors have a single electrical connection, with 2 wires in it. unplug that and there is no way for any fuel to flow through it unless it is leaking. Quote Link to comment Share on other sites More sharing options...
Chris2012 Posted November 6, 2013 Author Report Share Posted November 6, 2013 injectors have a single electrical connection, with 2 wires in it. unplug that and there is no way for any fuel to flow through it unless it is leaking. Leakage wouldn't be a bad thing at this point. Well ... pull one injector plug out, and you have 2 parallel banks, 1 with.2 injectors, in parallel with each other, and another bank with 3, also in parallel with one another. 1st bank, 6 ohms (assuming all injectors have about the 12 I could measure individually), the other bank of 3, 4 ohms. Together that makes 2.4, I measure 2.6. Doesn't seem like a short. If I unplug both connectors, I measure 3.2 ( 2 banks of 2 each). Ideally 3.0 ohms. Close enough? Seems so. Therefore I have to conclude there's no shorting going on. I think I may try "pulsing" manually 1 injector, or the remainder of the circuit, with 10 or so volts, while cranking, to see if the car tries to start. If not, I'm going to have to assume corrosion of the fuel rail or something. I could just pulse them with the key on ans smell for gas I guess. I think I would have to pull the injector harness from the ecm, but then I may be eliminating other relevant signals. Don't know. Quote Link to comment Share on other sites More sharing options...
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