3.0L V6 Fuel Pump & Inertia switch
 

Hello, I am new to these forums just looking for some opinions from others. (If this is in the wrong forum thread please let me know)

I drive an 02 ranger and whenever it gets cold where I live, I always start to have problem with my truck, at least I have in the last couple years. This year after I did some self diagnosis I found out that it could be my fuel pump/Inertia switch that may be messed up. I go to start my truck and the engine won't turn over. After messing around with some things, when I reset my inertia switch, after a couple of times of trial and error of starting the truck while simultaneously reseting the switch, my truck will start up and will start for a couple times before I would have to reset the switch again for it to start. I did a quick switch bypass and it started up so I believe that it is my switch that is messed up.

So, an opinion that I am asking, because after starting it a few times I would need to reset the switch again, Would it be smart to believe that I need to just replace the switch and the wiring going into the switch or do something else with it. That being look into the fuel pump wiring or more.

I am in no way a mechanic and don't have too much knowledge with maintenance so any thoughts would be appreciated.

"Turn Over" and "Crank" are the same thing, your inertia switch has nothing to do with that.

But a turn over/crank and not start/fire your inertia switch could keep it from starting/firing.

If you are having to constantly reset the inertia switch it's time to replace it, once they have been tripped replacement is usually the best.

Here is a helpful video:

Welcome to the forum Ryan

As said starter motor not working is different than engine not starting
No crank or no turn over means starter motor is not working

If that's the case then in a 2002 Ranger its most likely a PATS(passive anti-theft system) issue, but there should be a fast flashing light on the dash, theft light, which you don't mention
PATS can cause intermittent No Crank when battery gets too old or is not being charged by alternator when driving
Cold temps lower the power in ALL car batteries, so that could only show up in winter months

If starter motor does turn the engine over every time but engine doesn't start, then it could be inertia switch, inertia switch sends 12volts to fuel pump inside the gas tank
If the vehicle was ever in an accident and the inertia switch was TRIPPED then it should have been replaced, but often isn't, so it can be tripped again and again just by closing a door or going off a curb
But inertia switch issue would NOT be temperature related at all

Next time there is a crank but no start try turning the key OFF and ON 3 times, and THEN try to start engine, if it starts up then your problem is loss of fuel pressure when truck is off longer than a few hours, not uncommon at all, but NOT outside temp related


ECT(engine coolant temp) sensor tells the Computer how much CHOKE to apply to start a COLD engine, so very temp related
Gasoline engines need to be choked to start cold, but when started engine would run rough until it warmed up in a few minutes, so if thats not the case then it isn't ECT sensor issue