“New” cars, collisions and fuel cutoff?

Joined
Jan 2, 2004
Messages
10,748
Location
California
I was almost a witness to a crash, newish Honda and a older Scion kissed and airbags were deployed on both cars. Both of them were able to be started and driven to the side of the road. I thought when the airbags are deployed on newer cars, the fuel pump was disabled. Is that not the case?

I know Fords usually have a fuel inertia cut-off on them, which I haven’t seen in a while.
 
Ford is the only manufacturer I know of that didn't use an auto shutdown relay that automatically reset.
 
You would have to manually reset. The switch was in the trunk...wasn't it?

Yep, passenger footwell for trucks and SUVs. A friend that had a Ranger slammed the brakes on and a book on the seat flew off and hit it. He didn't know about the reset button and had it towed. 🤦‍♂️
 
  • Like
Reactions: CKN
Yep - when our Tahoe was rear ended - side airbags and seat locks fired - fuel supply off …
Battery was down low after all that anyway …
 
Yep - when our Tahoe was rear ended - side airbags and seat locks fired - fuel supply off …
Battery was down low after all that anyway …
Yea, that’s what I thought, airbags and pretensioners get deployed, fuel supply or spark is disabled unless repairs are made and codes are cleared. I was surprised both cars were still running when I walked past.
Yep, passenger footwell for trucks and SUVs. A friend that had a Ranger slammed the brakes on and a book on the seat flew off and hit it. He didn't know about the reset button and had it towed. 🤦‍♂️
I’ve seen them on the driver’s side footwell on the 1993-1997 Nissan Quest/Mercury Villager, both built by Ford in Ohio. I’ve admit to triggering it during a fuel filter replacement as a lazy way to depressurize the fuel system.
 
In some vehicles, fuel cutoff is a function of the Airbag Control Module (Or SDM for Chev, RCM for Ford, etc.) based on collision severity. Given that it's an electronic module, it wouldn't need to have a physical switch manually reset. On that basis, it could be programmed to allow the fuel pump to run on the next ignition cycle. If someone who isn't mechanically savvy (or inclined to read a manual) has a relatively minor collision that results in airbag deployment but doesn't totally disable the vehicle, you wouldn't want them stranded in the middle of nowhere in the winter due to fuel cutoff.

Also, the threshold for airbag deployment may be different than the threshold for fuel cutoff, so you could have deployed airbags and no fuel cutoff, depending upon how the system is configured.
 
The fuel cutoff, if working properly, doesn't activate for minor crashes where engine damage isn't likely. With the old inertia switches this could happen if you hit a pothole too hard.

The manual probably has a procedure to reset the fuel cutoff, it's not something you will find by luck so if it activates you're not likely to drive off. The car won't be driveable either, imo...
 
Yep, passenger footwell for trucks and SUVs. A friend that had a Ranger slammed the brakes on and a book on the seat flew off and hit it. He didn't know about the reset button and had it towed. 🤦‍♂️

I caught a pothole so bad in my Taurus that I tripped the inertia switch! What's funny is , after that, I could slap the right rear fender with an open palm and trip the switch. Was pretty useful for when people wanted a ride (was in college at the time) and I didn't want to give them a ride.

Give the car a good slap and then it wouldn't start. Sorry, can't give you a ride!
 
Ford is the only manufacturer I know of that didn't use an auto shutdown relay that automatically reset.
My high school friend had a 1990 Probe that hit a large pothole, and the switch activated. We chased that issue for a minute (fuel pump, plugs/wires, distributor) and then learned to go into the trunk and hit the switch to make it run again. Dummies!
 
My aunt got rear ended in 2017 in her 2016 Avalon, no airbags deployed but it shut the car off. She restarted it to drive to the side of the road.
 
Seems like simple restart would be best path for that. A mechanic involved is crazy design to move a car safely out of path of traffic.
 
Seems like simple restart would be best path for that. A mechanic involved is crazy design to move a car safely out of path of traffic.
there's a real fire hazard if fuel lines are ruptured. Pressurised fuel isn't a joke, especiually if there could be electrical shorts and hot exhaust parts exposed.
 
I have an '02 and '05 Ford with reset buttons in the trunk/rear. A good point is made - I mean yeah you want the pump to shut off if you go tumbling but not while you're in the road stopped.
 
09 Ford Powerstroke at work has an inertia switch in passenger side footwell. I owned many 80s fuel injected Fords years ago and remember the locations of each one still to this day.
 
Back
Top