On "Microsquirting" the Porsche 914

Ignition Coil, Bracket, and Injectors

Back to Part 4

Remember the IGN4-VW coil? Install was going to be a breeze...or so I thought. I tossed around several location ideas and wasn't happy with them. Then EricP showed me a bracket he made to install his in the area where the original distributor was...of course! Duh. Eric fabbed a bracket that also mounted his MPS, but since I didn't need that I "went simple" and made a plate out of sheet metal I had laying around. It fit right over the distributor hole plug and used the distributor clamp stud and two sheet metal screw holes. Drill, tap, three rivnuts later and the coil was mounted.

3/28/22 Update: Please read Part 11 Addemdums. I no longer recommend mounting the coil here, as it was overheating and causing misfires. Description and photos left for reference -- of what NOT to do... ;)

By the way, this wasn't the first time Eric saved my bacon...the TPS choice and TPS mounting bracket was his idea too...

The credit card had rolled over and I ordered the FiveO Motorsport injectors. As suspected, they bolted right into the original D-Jet locations and even came with new seals.

FiveO injectors on left, original D-Jet on right

The FiveO injectors come with straight hoses versus the D-Jet's curved hoses. The 914 needs curved hoses to clear the engine compartment frame rails. These are available from any 914 supplier, such as Pelican Parts.

Note the photos here describe the mock-up, using the the straight hoses that came with the injectors. Trust me, you want the curved ones.

FiveO Injectors installed in D-Jet location

Here's the engine with a few more parts installed! Prosit!

On to Part 6: "Ignition, Wiring, and Terminals, Oh My!"

TDC - Top Dead Center, the firing position for #1 cylinder
CPS - Crank Position Sensor, also known as CAS, Crank Angle Sensor
TPS - Throttle Position Sensor
MPS - Manifold Pressure Sensor
IAT - Intake air Temperature sensor
CLT - Coolant temp sensor
AFR - Air-Fuel Ratio
FLAPS - Friendly Local Auto Parts Store

Comments

Bosch D-Jetronic The Bosch D-Jetronic system is pretty cool, especially when you consider it was designed in the 1960s. "Computer"-controlled electronic fuel injection with manifold pressure sensor, intake temperature sensor, crankshaft (well, distributor) angle sensor, and throttle position sensor/switch. It uses constant fuel pressure and flow, so only injection duration needs to be modified to control air/fuel mixture. It measures incoming airflow by monitoring the intake manifold pressure; engine speed, temperature, and other factors are monitored for the purpose of fine-tuning injection duration. Ignition is by a standard cam-driven distributor with an internal D-jet-specific pickup for the crank/cam angle position. This "speed-density" D-Jet system was used on many cars of the period, including Volvo, Jaguar, Volkswagen, and of course, the Porsche 914 (1.7L and 2L engines only; the 1.8L used L-Jetronic -- "L" for "luft" or "air...

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