Porsche 944 models are beloved by their owners. But just like with any other vehicle, it’s not so great when they won’t even start.
But, don’t worry! You’ve come to the right place.
The most common problems when your car won’t start are DME Relay, Reference sensors, and Coil and its wire.
In this article, find out everything you need to know about each. And learn the right ways to solve them all!
What Can Cause the Spark Problem?
Several things can cause the missing spark, which creates the general problem that your car won’t start.
This can create panic in most owners, but if you know how to fix it or even where to look for a problem, you are already in the middle of the journey of fixing it.
Some of the most common things that can cause your vehicle to miss a spark are:
- DME Relay
- Reference sensors
- Coil and coil wire
You will find all about those problems and their solutions if you keep reading!
First Cause: DME Relay
The DME relay is one of the first things you should examine if your Porsche 944 won’t start or dies unexpectedly.
The relay is a fuel pump relay on earlier 944s.
And you can find it on the fuse panel under the dash on the driver’s side.
So, the relay is placed in the fuse/relay panel in the rear left side of the engine compartment, next to the windscreen and A-pillar on later 944s and 951s.
These relays are prone to failure, and they tend to fail frequently.
So that can be a problem that is causing your car to lose spar.
They usually fail due to damaged circuit joints. However, they can also fail due to diode failure or heat sink concerns.
If you’re going to drive a 944, get a few additional DME relays and keep a spare on hand.
Even the spare fuse has room in the fuse box. Purchase an extra relay and replace it with the one working correctly.
The new relay is in good working order if the automobile starts and operates smoothly.
Replace the fuses and the spare in the fuse box. While all these tests will aid in diagnosing a problem, it is still more convenient to install a known good relay.
The one thing to keep in mind:
The 944 Porsche cars have a total of two relays.
The first one powers the DME and KLR on the 951 Porsche vehicles.
The other one powers the heater and fuel pump for the O2 sensors.
If you want to fix the problem yourself, here is a quick video that can serve you as a guide or even an introduction.
Second Cause: Reference Sensors
One of the first places to look when troubleshooting hard starting issues or a car that won’t idle is the speed reference sensors.
Two crankshaft sensors are used in the 944 Engine Management system.
One (Reference Sensor) detects the location of the number 1 piston (front of the engine) in relation to TDC (TDC). The highest point of the piston on the compression stroke is referred to as TDC.
The Speed Sensor, which is the second sensor, keeps track of the flywheel’s teeth.
Then it sends a signal in the form of pulses to the Engine Management Computer (DME), showing engine speed in RPM (Revolutions Per Minute).
The DME can detect the engine position at any point in its cycle by combining the two signals and applying the proper fuel injector cycling and ignition firing.
The DME uses the speed sensor’s signal as a safety feature to shut off the fuel pump if the engine speed goes below 300 RPM (after initial cranking is complete).
Different starting and operating issues can be traced back to the speed and reference sensors.
This technique explains how to check the sensors’ functionality.
It also explains how to repair and modify the sensor clearance if it becomes damaged.
You can find the sensors in the back of the engine, on the top of the clutch housing. You may find them by glancing down at the rear of the engine near the firewall from the driver’s side of the automobile (left-hand drive).
However, if you want to fix it, there are two options:
- You can do it by yourself by watching this video and following these well-explained instructions
- You can take it to the mechanic to do it for you
Third Cause: Coils
The ignition coil transforms the ignition voltage into extremely high voltage pulses (20,000 volts or more) that ignite the spark plugs.
The number of ignition coils varies by vehicle type and manufacturing year.
Older automobiles will have a single coil that covers all the engine cylinders.
However, modern cars may have a coil-on-plug system, in which each cylinder has its specialized ignition coil.
Here are some steps which could help you solve the problem:
Step 1: Ignition
Check the ignition first! You have to ensure that it’s off.
Step 2: Separate the Coil
Separate the coil from either a bracket in the engine compartment.
Or, in rare circumstances, from within the distributor for single coils that supply all cylinders.
Reconnect all electrical connections and secure the replacement coil. Modify the timing as needed if you removed the distributor for whatever reason.
Step 3: Remove and Test
Remove the coil from the top of each spark plug and change it in coil-on-plug systems.
Now, you should road-test the automobile to assure proper operation when:
- A. the coil is firmly installed,
- B. you reattached all electrical connections,
- C. you’ve adjusted the timing as appropriate.
Step 4: Things to Keep in Mind
If you’re doing this, keep in mind:
- Your ignition might fail due to the faulty (spark) plugs. If you see a mechanic, they will evaluate the components and may recommend that they be changed. It is also recommended.
- In a coil ignition system, you must replace only one coil if it breaks. Coils that are still in good working order can be kept in place.
- In systems where the coil is located in the distributor, it may be more cost-effective to replace the entire distributor rather than just the coil.
The problems listed above are the top three reasons for the faulty spark. However, they are not the only ones.
If the above doesn’t solve the issue, please make sure to take your dear Porsche to a professional.
Luna Meschiari is a full-blooded car nut who is well known to local garages, as each article is meticulously researched and peppered with the latest piece of information. Guess what car she’s driving right now? A RAV4 2021 Hybrid. But her heart also sleeps for pickups like the F-150. Get to know Luna better on the about us page.