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Low impedance injectors not working with PWM
Posted: Mon Jun 02, 2008 9:21 am
by rootesrefuge
I'm running a 1725cc 4 cylinder, MS1 on a 3.0 board running a pair of Saturn TBI injectors (small Delphi style), one per driver. Wired the car without resistors, planning to use the PWM on the 3.0 board. But if I set both the opening time and timing threshold to 1ms like the instructions say, it won't run. I've tried the whole normal range of injector opening times, with no difference. I've been running it for a few miles with the threshold set to 10ms, but I know that has to be stressing the circuits. Even with it running, if I set the timing threshold below the pulse width it dies. Any thoughts or suggestions??
Re: Low impedance injectors not working with PWM
Posted: Mon Jun 02, 2008 12:32 pm
by rootesrefuge
Lance,
The Delphi specs show them as 4/1 peak&hold, so I hadn't tried going above 30%. I'll try that tonight and report back. It would help if I had access to an oscilloscope, but no such luck.
Thanks!
Re: Low impedance injectors not working with PWM
Posted: Tue Jun 03, 2008 5:23 am
by rootesrefuge
Update -
Set the time threshold and opening time both to 1ms, and upped the percentage to 50%. Still nothing, so I figured I'd try working my way down. Set it at 75% and it ran fine. Dropped it a percent at a time until it died at 65%. Right now it's set to 70%, but I'll try lowering it again under different conditions/temperatures. Fortunately I'm only running one injector off each driver, so hopefully there's not much risk of burning anything up. Getting a second pair of injectors will probably be my next test.