

| Subject: | Re: Any way to trick the Digijet ECU into generating injection pulses without the RPM/ignition signal, for test bench purposes? |
| From: | David Beierl |
| Date: | Sat, 2 Jun 2012 15:37:50 -0400 |
At 05:08 AM 6/2/2012, tinker man wrote: >I'll get down to testing that myself soon, but was wondering if anyone >has already tried this or has other ideas. The output driver is FET equivalent of an open-collector, i.e. it supplies a ground when it's active and open circuit when it's inactive. Connecting and disconnecting things while it's powered is a no-no. Damage is cumulative and actual failure may occur some time later. (General rule on the ECU is not safe unless they specifically say it is.) Suggest trying a logic pulser set on TTL and powered from 5 volts. Check Bentley for specs but I believe it's a 5-volt pulse, so TTL logic margins may be enough. Or in CMOS mode, adjusting supply voltage to get desired output voltage. Otherwise build a triggerable 555 circuit that will output a pulse stream for you at the desired voltage. That may be easiest if you don't have a scope to measure the output of the pulser. If the datasheets at National Semi etc don't have a suitable circuit there will be one somewhere on the web. Yours, d
Have something to add on this topic today? Revive this thread in the forum »