My favorite three tools for Troubleshooting

Open the hood of a Jaguar V12 and all you see is wires and tubes. It terrifies novices and even a lot of mechanics  but not just V12’s  any engine in any car 

but with the aid  of three cheap tools you can easily trouble shoot problems.   Prices are current Amazon prices  

The first is a digital infrared sensor.  It’s a $16 plastic handle tool you point at what you want to take the temperature of, A little red dot illuminates what you are pointed at and you get a read out.  

Aim it at the exhaust port of each cylinder and if it’s cooler than the others that one isn’t working.  

Since a V 12 is so smooth even when running poorly it’s a great help.  

Next you need to find out if it’s spark or fuel issue.  

I use a $8 inductive lead tester. Lay it on  a spark plug wire  and if it flashes the wire is good. 

 Finally a mechanics stethoscope  $16.00   Hold it against the suspected fuel injector and if you hear a clicking the injector is working.  

All  of those tools have dozens of other uses.

Infrared sensor,

check brake temps,  front to back left to right, , tire temps,  read the walls in your house for cold air leaks.  Heat registers for proper heat distribution. Dash vents in your car for air conditioning temps   Transmission temp, rear end temp, 

inductive spark detector?

Is a electrical wire on or not?  Turn off the breaker but sometimes a circuit is back fed ( ask me how I found out)  

mechanics stethoscope  

sound of anything.   Is the bearing in the alternator going or is it the idler bearing?  Oh? the water pump?   Valves properly adjusted?  Is that knock a rod bearing or the main bearing? In short the sound of anything. With just a little bit of experience you’d be amazed at what your ears will tell you. 

Awesome post. Last year I found a novel use for my mechanics stethoscope - finding the location of a yellow jacket nest inside the walls of my house!

I've found a 12v test light invaluable when working on electrical in a car. Clip the lead to ground and get to poking to make sure a signal is making its way all through the car. A good one can be had on Amazon for around $10.

In reply to dculberson : That’s a new one on me!!!   I’ll use it to check the oak Timbers in the house to listen for the death watch beetle. 

As for a test light?  Amen!!!! Especially with British cars.  

Another tool that’s very handy is that mighty mite mini vacuum.  Plug a vacuum line into a hose and see if the hose is leaking.  Or the vacuum advance unit etc.  

it’s really important on Jaguars because they have one hose that goes from the engine all the way into the trunk  where the computer is kept!  Absolutely no way to check the hose without one.  

But you can also bleed brakes by yourself with It and check vacuum operated windshield wipers.   My garbage disposal is air pressure operated and I trouble shot that unit with it.