Long cranking - Page 4 - ZR-1 Net Registry Forums

Macroblock · 07-09-2020

I didn't like the original factory start-up procedure because it takes far too many cranks before the engine starts. This is due to the ECM delaying fuel delivery.

When the engine is turning over, the crankshaft sensor sends a pulsed signal to the Ignition Module. Every revolution produces a sync-pulse (odd-pulse). Once the ignition module synchronizes, it sends consecutive signals to the coils and sends a pulse stream to the ECM. When the ECM detects the pulse, it activates the fuel pumps, waits a moment or two, then pulses the injectors.

Due to the failure of component U13 in the ECM, I added a general-purpose-microcontroller and wrote custom firmware which now controls the 8 injectors. On start-up, the new MCU monitors the coolant temperature sensor and engine RPM and when appropriate, hi-jacks the start-up process.

For the first time ever, my ZR1 now starts with the first spark in cold, warm or hot conditions.

vanvan2801 · 08-17-2022

Hello,

In general, ZR-1s take a few seconds to start. My 93 starts instantly, not even giving the oil pressure time to build up (cold or hot engine). Where do you think this symptom comes from ? Crankshaft sensor failure ?

Thanks for your answers!

Sent from my iPhone using ZR-1 Net Registry

07-09-2020	#31
Macroblock Join Date: May 2020 Location: Windsor Posts: 39	Re: Long cranking I didn't like the original factory start-up procedure because it takes far too many cranks before the engine starts. This is due to the ECM delaying fuel delivery. When the engine is turning over, the crankshaft sensor sends a pulsed signal to the Ignition Module. Every revolution produces a sync-pulse (odd-pulse). Once the ignition module synchronizes, it sends consecutive signals to the coils and sends a pulse stream to the ECM. When the ECM detects the pulse, it activates the fuel pumps, waits a moment or two, then pulses the injectors. Due to the failure of component U13 in the ECM, I added a general-purpose-microcontroller and wrote custom firmware which now controls the 8 injectors. On start-up, the new MCU monitors the coolant temperature sensor and engine RPM and when appropriate, hi-jacks the start-up process. For the first time ever, my ZR1 now starts with the first spark in cold, warm or hot conditions.

08-17-2022	#32
vanvan2801 Join Date: Jul 2020 Location: Belgium Posts: 31	Re: Long cranking Hello, In general, ZR-1s take a few seconds to start. My 93 starts instantly, not even giving the oil pressure time to build up (cold or hot engine). Where do you think this symptom comes from ? Crankshaft sensor failure ? Thanks for your answers! Sent from my iPhone using ZR-1 Net Registry