about inertia switch

[MiguelH]

Hi,

My truck doesn't start. I did run a search about this situation and i found this thread Nº 11066.

Ewald G Gruber says:

I am reading chapter 4; FUEL and EXHAUST SYSTEMS of the Haynes Explorer 91-95 repair manual.
There,they talk about the FUEL PUMP SWITCH or also called inertia switch.
It is located on the passenger side of the transmission hump on the firewall under the carpet-unplug its electrical connector and crank the engine for 15-20 seconds to relieve fuel pressure. When done with your work, reconnect the electrical connector back onto the swich and push the reset button on top of the switch.

I will try this option for tomorrow, but before i would like to know more about the function of the inertia switch. It is possible start the engine with the inertia switch disconnected?

 

[Stephen S]

According to what the Haynes amnual says right there, the engine won't start with the inertia switch disconnected. It appears the Haynes manual instructions are explaining how to relieve the fuel pressure by manually turning the fuel pump off (by disconnecting the inertia switch) and then cranking, not starting, the engine for 15-20 seconds (meaning just turn the key to ignition and let the starter turn the engine to relieve the fuel pressure). So no, the engine will not start with the inertia switch disconnected.

I do not believe that doing this will fix your problem and make your truck start. When you turn the key on, do you hear your fuel pump turn on for a second or two to prime the system?? If you can hear your fuel pump kick on when you turn the key, then there is nothing worng with your pump or the inertia switch. The problem must be with something else.

 

[MiguelH]

Thanks a lot Stephen!

Oh well, the truth is, a couple days ago, i was involved in a collision, the engine starts ok after that, and i went with my brother. But when i wanted to start the engine, just crank and crank but doesn't start.
The owner's manual talk about the shut off switch, for the case of a collision, and i tried the procedure indicated there. It Didn't works.
Then, i come here and the last two days i've been searching about problems when engine doesn't start. I tried just disconnecting shut off switch and turn key on (as manual says), without the 15-20 secs.
Maybe it works.

Oh, by the way, fuel pump and fuel filter are new, i don't have voltymeter but fuses looks ok.

If doesn't works, i'm thinking in replace 02 sensor, fuel pump relay and maybe crankshaft sensor, well if i can get it all them. Battery cables change are on the sight too.

This was the resolution of my search. Just i had that question about inertia switch.

I will inform the results.

 

[Jason_25]

I can tell you it is definitely not the 02 sensor that is keeping it from starting.

 

[Stephen S]

No problem man, happy to help. Well, if you were involved in a collision, then the inertia switch may have been tripped. The inertia switch shuts off the fuel pump in the event of an accident so that it doesn't pump fuel out into the street everywhere and pose a fire hazard. I would try resetting the inertia switch. Slide under the passenger side dash board and press the reset button on the inertia switch. This will reset it, and make the fuel pump work again. This could be all your problem is. I'd try this before I started changing parts.

 

[MiguelH]

well, she didn't start.

Maybe i didn't the procedure in right order.

Please, could you showme step-by-step the right order. Starting from the truck is parked.

Another question, Must be the truck in leveled surface, Is this mandatory ?

Thanks.

 

[Stephen S]

I don't think that there is a "procedure" to resetting the inertia switch. I think it's just as simple as pressing the button on the unit itself. It's also possible that this isn't the reason your truck is not starting. You said it cranks and cranks but doesn't start. You also mentioned that the fuel pump and filter were new correct? It sounds like a fuel issue to me. Do you hear the fuel pump turn on when you turn the key on?

 

[MiguelH]

you was right!,

fuel pump guilty.
Thanks for your advice. I commented it to the shop's mechanic.
It was changed and filter too, of course.

Oh, btw i have now the haynes and chilton's manuals.

I think they will be of big help. For futures references.

Sorry about the late, i've been very busy, i've been looking for job, you know interviews, visiting people, etc.

See you, and thanks for everything again.

MiguelH

 

[Stephen S]

No problem Miguel. I'm glad to have been able to help. Good luck with the job search!!