Car Talk: Twist ties dangerous alternative to clips to hold fuel-injectors in place
Q. I’ve been a fan for years. I had a great 2000 Ford Crown Victoria, which I always had serviced at a local muffler/repair shop. Last year, I gave the car to my daughter in Michigan. When she took it to her own mechanic for a tuneup, he discovered that all eight fuel-injector clips had broken off and the fuel injectors were held in position by plastic zip ties! My repair-shop owner is telling me that there is a problem with these clips, that they tend to break off, and that it is standard to use zip ties to hold them in place. He never mentioned this during the nine years he serviced my car. My daughter’s mechanic says my guy is “blowing smoke,” and he has never seen anything like this before. Who do I believe? I am very leery about returning to my old guy now with my newer 2005 Mercury. What do you fellows think? Would you go back to him?
TOM: No. He’s endangering your life. And he’s trying to cover up his bad judgment with a song and dance.
RAY: We used to try that, but very quickly, we ran through the entire 20th Century Songbook, and our feet were killing us.
TOM: Those clips do break sometimes. We’ve seen it happen when you remove the fuel injectors to make a repair. But if you break one, or two, or eight, you buy new ones. They’re sold separately by dealers, and they’re cheap. Very cheap.
RAY: So the only reason to use zip ties would be laziness. They’re not an acceptable substitute.
TOM: They’re plastic, so they’re not designed to take the high underhood temperatures in the middle of the engine compartment, which can be several hundred degrees. And over time, the zip ties will get brittle and fail. If one breaks, a fuel injector can come flying out, spraying gasoline at high pressure all over the engine.
RAY: And that leads to what? Fire. So, to summarize: bad idea!
TOM: We use zip ties all the time to group bunches of wires together, or hold a wire out of the way if it’s at the periphery of the engine compartment - and if the zip tie’s failure would not result in anything dangerous happening. But we’d never use one to hold an injector in place.
RAY: To say that it’s “standard to use zip ties” to secure fuel injectors is nuts. It’s standard to use zip ties to close kitchen garbage bags. And if your guy doesn’t know that, it’s time for a new mechanic.
Q. Recently my husband and I rented a Toyota Prius in California - which we enjoyed driving, by the way. While driving in our many national parks, I was concerned that there seemed to be no way to downshift the car. Navigating the steep, winding roads caused me to worry that the brakes would overheat. Thankfully, this did not happen. So, what’s up with this vehicle? How does a driver prevent the brakes from overheating when cruising down these hairpin curves when there seems to be no way to drop the car into a lower gear? I really don’t want to use the Fred Flintstone braking method! It would ruin my shoes! Thanks for answering this.
TOM: While you can’t downshift the continuously variable transmission (CVT) in the Prius, they have created a simulated downshift mode just for this purpose.
RAY: If you look at the transmission selector, in addition to “P,” “N” and “D,” you’ll notice there’s a selection called “B.” That’s for “braking” mode.
TOM: Like most functions on the Prius, what it does is controlled by the car’s main computer, and the details are pretty complex. But from the driver’s point of view, what the “B” setting does is add a “braking” effect, just as if you were downshifting. You’d use it the same way, to prevent the brakes from overheating on a long, steep downhill grade.
RAY: If the car’s battery is at less than optimal charge, the “B” mode will first engage regenerative braking, which uses the forward motion of the car to charge the battery. That creates a drag on the wheels, which slows you down a bit.
TOM: If the battery is already sufficiently charged, or the speed of the car is higher, and the computer determines that it needs more engine braking, the computer then engages the engine through its planetary gear set and makes use of the cylinder compression to slow the car, just like every other car does when you shift to a lower gear.
RAY: These two braking effects can be combined by the computer, depending on the speed of the car, the condition of the battery and the amount of braking that’s needed.
TOM: So that’s the complex answer. The simple answer is that you shift into “B” and drive.
Got a question about cars? Write to Click and Clack in care of this newspaper, or email them by visiting the Car Talk website at www.cartalk.com.