Delphi Ignition Coil Review

Ignition coils are an essential part of any vehicle that uses an internal combustion engine. The ignition coil transforms current from the battery into a high voltage that arcs around the spark plug in the engine. This arcing voltage ignites the fuel and starts the engine. This basic principle has been used to jumpstart petrol engines for over a century and has remained unchanged even as engineers incorporated more electronics into the ignition coils. 

As the main purpose of an ignition coil is to essentially act as a small transformer, stepping up the measly 12 volts from the battery into the thousands of volts that are needed to create an electric arc and ignite the fuel-air mixture, a faulty ignition coil means that your engine won’t be able to start. In such a scenario, you will need to change your ignition coil. While there are countless brands out there, this review will focus on Delphi’s ignition coils.

Charles Kettering's inititial ignition system
Image credit: Denso Automotive

And starting the car isn’t the only purpose of an ignition coil. With the addition of complex electronics over the years, ignition coils contain the sensors that regulate the amount of fuel entering the engine. Having a faulty ignition coil means that your car is going to have terrible fuel economy. You will also experience misfirings, stalling, low engine power, vibrations, and jerking.

Are Delphi ignition coils any good?

Delphi Technologies is a London-headquartered company that has been making ignition systems for over a century. The company was part of General Motors before GM spun off into an independent auto parts maker in 1999. It renamed itself in 2017, spun out its powertrain business, and finally merged with fellow auto parts make BorgWarner in 2020.

Delphi Technologies is a leading innovator in the ignition, fuel economy, steering, and compression spaces. Delphi provides both aftermarket car parts and supplies said parts to established motor vehicle manufacturers.  

Are Delphi ignition coils made in China?

Sadly, like many other western companies, Delphi has moved a good chunk of its manufacturing to China in order to save costs. This has caused no noticeable decline in quality. The build quality is as robust as ever. However, there’s a major problem with counterfeiting. Ignition coils aren’t that hard to knock off. To avoid being ripped off use to find licensed Delphi resellers and service centers.

Delphi ignition coils review: BMW compatibility

Delphi is one of BMW’s Original Equipment Manufacturers (OEM) for ignition systems alongside Bosch and Eldor. You shouldn’t have to worry about compatibility. While the ignition coil in your BMW may be stamped with the iconic blue and white spinning propellers, it’s almost certain that it was made by either Delphi, Bosch, or Eldor. These coils are also interchangeable on many BMWs. The part number for BMW’s Delphi ignition coils is 12138616153.

A yellow BMW racecar with black accents

BMW claims that the reason BMW-branded ignition coils from the dealership cost more than the very same part with the manufacturer’s brand on it is testing and quality control. This is rarely the whole story. Dealerships often charge double what Delphi charges for what is essentially the same product in fancier packaging. It’s clear that both the company and the dealerships are tacking on their own markups. By buying directly from the OEM, you cut out two middlemen. 

Delphi ignition coils review: Reliability and performance

Delphi coils are built very robustly with a hard metallic shell. The wires are wound around a proprietary steel core and insulated with epoxy to prevent touching. The company uses a special vacuum technique to remove air bubbles from the epoxy which might otherwise compromise the insulation.

With such robust construction, there’s no reason your Delphi ignition coil shouldn’t provide flawless performance for 100,000 miles. As long as you take care to avoid knock-offs, you will have little reason to complain. The company sweetens the pot by offering a three-year warranty on its ignition coils. The mileage cap on the warranty is 36,000 miles.

Delphi ignition coils review: Installation

Delphi ignition coils are extremely easy to install. They are as close to plug-and-play as you can get with car parts installation. You still have to adhere to certain safety standards, however. 

You’ll be dealing with high voltages so the first thing to do is disconnect the battery. It’s also a good idea to wear gloves. They not only keep your hands clean from all the engine grime but also protect you from static and electric shocks in the vent you forgot to disconnect the battery. And there’s always the standard disclaimer: if you don’t know what you’re supposed to do under the hood, find someone who does. 

Delphi ignition coils review: Cost

Delphi’s ignition coils retail for around $25 to $50 a piece depending on the model number. This is fairly cheap in absolute terms. Many engines use an ignition coil per cylinder so replacing a whole set of ignition coils will cost you a bit. Pricewise, Delphi measures very favorably against competitors like Bosch.