Low impedance injectors not working with PWM
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Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0).
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
The full forum rules are here: Forum Rules, be sure to read them all regularly.
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rootesrefuge
- MegaSquirt Newbie
- Posts: 3
- Joined: Sat Apr 26, 2008 12:26 pm
Low impedance injectors not working with PWM
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??
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rootesrefuge
- MegaSquirt Newbie
- Posts: 3
- Joined: Sat Apr 26, 2008 12:26 pm
Re: Low impedance injectors not working with PWM
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!
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!
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rootesrefuge
- MegaSquirt Newbie
- Posts: 3
- Joined: Sat Apr 26, 2008 12:26 pm
Re: Low impedance injectors not working with PWM
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.
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.