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Electrical Gurus, please explain this to me

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Ok, so I've been having issues with my fuel solenoid, I run dual fuel- gas/propane. Some days it starts right up on gas, other days it won't, been chasin my tail for almost a year, now. I think I found it?

The main question is, how do I show 12.5 V at the wire, and then only 6 V at the connection? Here, Meter is plugged directly into plugs.
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Then, when I go to plug in the solenoid, it shows 5-6V? The blades are in, and we're talking maybe 1/8-1/4" away from the 12.5V area?
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Is this what cheap Amazon Connectors will do? If so, have a suggestion? Am I seeing Amperage drop- now that the solenoid is drawing power? ETA: It's not Amperage, I proved this by connecting just blades with nothing attached, duh!!! Lol, so, cheap connectors?

I'm at a total loss here. I can start the Jeep in Propane, and then while driving switch to fuel, no problem, which, to me, kind of shows that the Solenoid is trying to super-low power, but may need that push of gas to fully open, atleast that's what makes sense in my mind, lol.

And some wonder why I won't go F.I. I'm much better at cogs, gears and Venturis and stuff, lol. That makes sense once I read it. Electrical stuff? Not so much.... thank you for the help!!
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Discussion Starter · #3 ·
Who crimped the connectors onto the wire before they were inserted into the plastic shell?
A poor crimp, or perhaps wire insulation in the crimp, could do that. Might even be poor spring tension in the female part of the connector.

Roger
Lol, me, I even soldered them into there. But yeah, maybe I did a bad job, it looks fine, but I've thought that before.

It's amazing, my dad is a Computer Engineer for the Naval Intelligence, builds robots to go get bombs and stuff. Me? I can barely tune a radio, lol.

I just picked up some of the bullet connectors, gonna try those out. Maybe these thin blades don't have enough surface tension. I have the female and male pretty tight on there. Or, maybe I don't have enough surface of the wire in the connectors. They are pretty thin metal.
 

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Test on the other side of the connector when you have the solenoid plugged in. I doubt you are losing anything through the connection. More likely that whatever is getting fed in when you connect the solenoid is resulting in a voltage drop. Could be acting like a resistor.

Edit: what are the 2 black wires connected to? Is that plug you showed the switch power to trigger the relay, or the output from the relay?
 

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Discussion Starter · #5 ·
I think it was a loose wire where it ties into the switch. Ugh!! I hate electrical stuff, lol.

I still ordered a larger solenoid, this style (AF111) has a .156" orifice, ordered one with a 5/16" orifice. Takes more amps, though, so I guess I'm rewiring anyway, lol.
 

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Well, I asked because sometimes we buy pre-made pigtails that might be rather poorly made.

It's amazing, my dad is a Computer Engineer for the Naval Intelligence, builds robots to go get bombs and stuff. Me? I can barely tune a radio, lol.
Don't beat yourself up over that. That's all training and practice. If you don't have the benefit of his background, well..........

I just picked up some of the bullet connectors, gonna try those out. Maybe these thin blades don't have enough surface tension. I have the female and male pretty tight on there. Or, maybe I don't have enough surface of the wire in the connectors. They are pretty thin metal.
Yeah.....we're seeing a rather large amount of crappily-made chinese connectors that don't do the job, some even in the short term.
Good to hear you found the problem upstream.

Roger
 

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Your test is kinda funky when it comes to hardcore diagnostics. It may or may not indicate a problem. The reason that I say this is that on your original test the connector is disconnected, your only load on the circuit is a high impedance meter, the complete circuit is broken during this test, blah blah blah.

What is happening prior to that point in the circuit matters when testing. If there is truly another load or resistance before that point. When the circuit is hooked up and live it will change expected voltages at a point like that. I am not sure what you have going on schematically on that circuit.

Ohmmeters show gross problems when testing. They will show a very hard core failure. They often times though miss bad connections. Ones that for example: I turn the key on and have full power to the entire vehicle and when I try to crank it everything goes dead. Learning to test for voltage drops dynamically makes these diagnostics very simple. Some folks have a hard time understanding it though.

Basic electrical training that involves understanding ohms law and then applying voltage drop diagnostics to it clears this all up. It makes one excel in the field. I am as much or more advanced in this (I am more advanced IMO) than I am at carbs and ignitions. JS.

I can help to learn you this stuff. (Bad grammar intentional) It is very deep. I think that it is simple. I have spent a lifetime learning it though. If you can learn ohms law well enough to get an idea of what expected voltages are on a circuit, you are on the way to being your own electrical guru. I have come across zillions of people in the industry that just never get it.

A very close friend of mine that is very equal on carbs and stuff always tells me that I can see inside of wires. Yes I can. I know how to.

I do test things with an ohmmeter. Sensors and stuff. I do not trust it to chase wiring or connection problems. It is a quick test to find the obvious but not the end all final test that a circuit can operate with its true current or amperage applied to it.
 
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