Hi guys...

Was changing o2 sensor passenger side yesterday, went to go start and as soon as I start battery, hazards are flashing and wont turn off. Car will crank but won't start. After some fiddling with unplugging, plugging back in o2 sensor car started.

Today, was driving and in a rush hit a pretty big bump. Engine immediately died and hazards went on, battery and everything else continued to work. Fiddled around for 20 minutes (unplug o2, unplug battery ect) somehow I got it to start....

Anyone with ideas? My gut says the alarm was not allowing the engine to start..

 

You may be correct but, a couple of thoughts, you always replace both front 02's at the same for balance air/fuel ratio of 14 to 1. Second you always clean the 02 connection with contact cleaner then use die electric jell to make the cleanest best connection.
How many miles on the engine, what are all your fault code numbers and have you ever replaced you CPS?

 

My money is on the inertia switch. Possibly connector jostled when changing the O2 sensor...

 

Well let me say this... When we were working we noticed the intertia switch dangling (broken mount) and didn't know wtf it was...Until I googled it after you mentioned it.

Go along with how i hit a hard bump when this happened I think you have it spot on.

I have since zip tied it back up and drove it.

 

Just to make sure we are on the right track, you might try hitting that same bump at the same speed to verify the zip tie repair is adequate, and that the inertia switch really was the culprit .

 

i had the same issue and did the same re-mounted it with a couple wire ties. I "believe" the flashers are an indicator that the inertia has tripped, but i'm not sure.

 

SO, you never replied to my questions that might help us find your real problem. The inertia switch is not the cause.

 

Mike, I kinda doubt it's the O2s since these trucks will even run with one or no O2s plugged in (albeit not as well), and I don't see how a bump could set off a bad O2 reading unless there were an electrical short in which case the engine would likely sputter then die, correct? I'm curious why you think it wouldn't be the inertia switch?

Please correct me if I'm wrong, but that is my line of thinking.

 

First, our truck can run without the 02's plugged in just not well.
If you hit a bump, yes it can trip the inertia switch shutting off the fuel pump and must be reset to restart the engine, but if you go back and read the first thread, that switch will not throw the flashers , that's like a 1668 open circuit fault, or something similar which is why I asked for fault codes.

 

Ah, ok. Thanks for the clarification. I didn't know if the switch would throw the flashers or not.