Low voltage injections signals problem

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Jo_Tercel99
MegaSquirt Newbie
Posts: 11
Joined: Thu Nov 20, 2008 10:07 am

Low voltage injections signals problem

Post by Jo_Tercel99 »

Hi, I have a problem with my injections signals. I use Magasquirt II V3 and I assembled it myself. I asjusted all parameters for high impedence injectors and I only get 2.10 V on the injectors signals . I also tried to set it like low impedence and it give me a 3.20V signal. So, i checked everything on the board and it seem fine. So now I don't know what to do to found the problem. If you need more informations feel free to ask.

Thank you
Matt Cramer
Super Squirter
Posts: 2951
Joined: Sat Jul 03, 2004 11:35 am

Re: Low voltage injections signals problem

Post by Matt Cramer »

Remember that the MS supplies ground to the injectors, not power. Given how fast the injectors switch on and off, it's near impossible to catch the voltage correctly with a volt meter, requiring an oscilloscope instead. Do the injector LEDs work on a Stim?
Jo_Tercel99
MegaSquirt Newbie
Posts: 11
Joined: Thu Nov 20, 2008 10:07 am

Re: Low voltage injections signals problem

Post by Jo_Tercel99 »

Oh yes thats right, so my problem is maybe somewhere else.

Yes everything seems well the LED are flashing, I don't have any problem anywhere esle but when I tried to start the car with Megasquirt it was like it was'nt injecting fuel. The fuel system is alright because I run the car every days with the stock ECU.
Matt Cramer
Super Squirter
Posts: 2951
Joined: Sat Jul 03, 2004 11:35 am

Re: Low voltage injections signals problem

Post by Matt Cramer »

Chances are you need to adjust the cranking pulse. But first make sure the MS is seeing RPM, since no RPM means no fuel.
Jo_Tercel99
MegaSquirt Newbie
Posts: 11
Joined: Thu Nov 20, 2008 10:07 am

Re: Low voltage injections signals problem

Post by Jo_Tercel99 »

Yes I get a RPM and I tried some différent Cranking pusle and it did'nt change anything, the car didn't start, so I checked at the exhaust to see if I could smell fuel but it didn't.
Matt Cramer
Super Squirter
Posts: 2951
Joined: Sat Jul 03, 2004 11:35 am

Re: Low voltage injections signals problem

Post by Matt Cramer »

Check the plugs and see if they are soaked with fuel. If not, add more cranking pulse width at the temperature you're at.
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