Mind-boggling wiring diagrams

Ray Magliozzi
Ray Magliozzi

Dear Car Talk:

Back in the ’60s and ’70s when my friends and I were kids working on our own cars, repair manuals always had the wiring diagrams somewhere toward the back of the book. Even back then, those wiring diagrams took up several pages with complicated drawings that always intimidated us. So we never messed with wiring.

Here’s my question: What in the world do the wiring diagrams look like now? My mind is boggled just imagining it. – Michael

RAY: The Oxford English Dictionary might need a word stronger than “boggled” for you, Michael. When we first opened the garage, we used to swap out a lot of VW engines. And when you pulled the engine, there were about five wires you had to detach. And you were done. Now, a typical engine compartment has 500 wires.

If we were talking about hair, it’d be the difference between Patrick Stewart and Martha Stewart.

Just think about the electronics on a modern engine. You’ve got electronic throttle, sensors galore, feedback systems, fuel injectors, safety systems and more. And we’re not even getting into the cabin electronics. There are a number of things that are done by printed circuit board. But there are still plenty of wires in there running from sensors to computers.

The good news is, hardly anything goes wrong with automotive wiring anymore. Today’s connectors are all weather-tight, and they’re pretty much designed to operate under water.

It used to be commonplace that wires would get wet, would rust or short out, or their connectors would corrode. But it’s rare these days that anyone has a problem with wiring, unless they crash the car and crimp 40 or 50 wires. And in that case, the biggest issue is finding the problem. You drive into the back of a Ben & Jerry’s truck, and six months later, you have no taillights and your seat heaters are permanently set to “add grill marks,” and you don’t know why.

By the way, electric cars, believe it or not, have fewer wires. They don’t have any of those sensors needed to keep a gasoline engine running smoothly and cleanly. They still have safety systems, and a computer, but due to the simplicity of an electric motor, they have many fewer wires.

So maybe you want to avoid looking at gasoline-engine wiring diagrams for now, Michael, and wait until we’ve all switch over to electric vehicles before having a look. But still, get permission from your cardiologist first.

This truck’s a piece of yellow fruit

Dear Car Talk:

Your recent article on used pickup truck reliability ratings (in which you steered a reader toward a Toyota Tundra) really made me chuckle. Since getting out of the Army in 1972 I’ve owned 15 Fords (cars, trucks, vans) for my ever-changing and growing family.

Currently I have a 2011 hybrid Ford Fusion that has never been in the shop, and we enjoy its great mileage. I also have 2018 Ford Edge with all the bells and whistles we love. Also amongst our family vehicles is a 2008 Toyota Tundra Limited, 5.7, V8 that had very high ratings from Consumers Report for reliability and was labeled a “best buy.”

Maybe there was a full moon the night before my Tundra purchase. There it was on the dealership floor, sparkling clean, almost winking at me to give it a test drive. I did and I liked it. I knew it would pull my 21-foot Chaparral boat, no problem. With a high rating, what could go wrong?

Here’s the list:

1. Loud piston slap when cold – piston slap is due to excessive piston to cylinder wall clearance. Toyota said this is normal.

2. Rear axle bearings were noisy and had to be replaced. Service writer said that’s not uncommon.

3. Power mirrors were replaced and one is bad again.

4. Water pump leaked and had to be replaced at about 50k miles. Service writer, once again, said that’s not uncommon.

5. Clear coat peeling. For over half of its life, this truck has been in covered parking at work and parked in my garage at home. The peeling is quite embarrassing. It’s so extreme it flaps and looks like it could challenge a bird for take-off.

6. The gas pedal practically gives my wife whiplash. It has been replaced, but still is very jerky when accelerating, much too sensitive.

Without mentioning any yellow fruit, maybe we just got a bad truck. But keep in mind the service writer said three of these items were normal and not uncommon. All this with less than 87k miles on it.

I don’t know if I want to laugh or cry. None of my Fords ever came this close to disappointing me. I do know for sure that I won’t rely on so called “ratings” from now on. How could anyone have given this Tundra such high ratings? Bewildered and frustrated. – Ken

RAY: Oh, you got a flapper, Ken. Who could ask for anything more! To be fair to us, we were asked about ratings for used pickup trucks 2014 and newer. We didn’t look at ratings for the 2008 Tundra. If we do that now, we see that it gets – oops! – 4 out of 5 for reliability.

I think we’d ding them on the piston slap. That is a common complaint about Tundras from this era, and I’d be teed off, too, if my truck did that. And we know Toyota had problems with its Pearl White paint peeling off. They should have taken care of that for you with a sincere apology. Same with the water pump.

What’s important to keep in mind is that ratings are just averages. It’s like using Yelp. If 15 diners have a great meal at a place and one guy gets food poisoning and throws up on the cheese plate at his kid’s bar mitzvah, the restaurant is still going to have a 4.7 rating overall. That’s better than the 4 out of 5 your Tundra got for reliability.

And any particular survey can suffer from built-in bias. For instance, if everybody who reads Consumer Reports has been reading for 40 years how great Toyota reliability is, that might subconsciously affect how, or whether, they report their experience in that survey.

There’s also the possibility that you got a lousy individual truck, Ken. One of those “Friday built” jobs. Our own experience in the garage lines up pretty well with what we reported. The Toyotas we see tend to be better than the Fords in terms of how often they need repair. But not every Toyota, nor every Ford.

So surveys, done by credible organizations with the largest possible sample size, while not perfect, are the best information we’ve got to go on.

Got a question about cars? Write to Car Talk write to Ray in care of King Features, 628 Virginia Drive, Orlando, FL 32803, or email by visiting the Car Talk website at www.cartalk.com.