Lost power to injectors, engine was running, works on stim

[beast02]

I have been tuning the car for the past few weeks trying to get the car drivable and on the road. Last night I went to start it up and do some more tuning and it was idling a lot more rough than usual. I found out that injector 1 was the only one firing (then), and now today trying to figure it out and get things running, I don't think any of them are firing. I checked voltages and when the one WAS running the engine, it was getting about 9V while the rest were getting about .15 . I tried the MS on the stim and both LED lights flash, but hooked up to the car and the computer nothing does (just the initial turn the key flash).

I checked the wiring, nothing seems to be shorting (as far as I can tell), I pulled the two fuses on the relay and traded them for new ones, that didn't seem to do it. I get a TPS signal, I get an RPM signal, I get spark.

I don't really know what else to check and what it could be. Because I get all those things working, it seems like the answer should be simple, but i'm just not coming up with it....

MSII, V3.0, EDIS, 2.88 code


Thanks,
Bryan

[steamer]

The injectors do not get power from the MS, they get their power from an external source and are grounded by the MS. With the main relay on you should see 12v at the injectors, if not, check your wiring.

[beast02]

I know it doesn't get power from the MS, but if the Megasquirt or code were the issue, then the stim would not have the injector LED's flashing like they are.

Wiring looks good, wire goes to injector from +12V, goes to relay for ground, no shorts, no loose wires.......

What could have changed that could be causing this, somewhere along the line something happened which is causing the injectors to not get power. Is the only place to look wiring???

[steamer]

I know it doesn't get power from the MS, but if the Megasquirt or code were the issue, then the stim would not have the injector LED's flashing like they are.

Just making sure we were on the same page on how they are wired.

Wiring looks good, wire goes to injector from +12V, goes to relay for ground, no shorts, no loose wires.......

The part I don't understand is "goes to relay for ground". Are you using the relay board and is that what you mean by "relay"? In your original post you said that you were seeing 9v at one injector and .15v on the others. What were you using for ground to make this measurement? If you are using the relay board have you verified that you are seeing 12v at the terminal block for the injectors?

What could have changed that could be causing this, somewhere along the line something happened which is causing the injectors to not get power. Is the only place to look wiring???

[beast02]

I was getting 9V on one, but don't seem to be getting it anymore. The car originally ran fine, then was down to 1 cylinder, now it won't start at all (not getting fuel)

I'm not grounding to the relay board, the ground wire just runs to the terminal strip where it then gets grounded (like its supposed to). I was checking the 12V block for the power to the injectors.

I'll have to run through my wiring again tonight, and double check if they are getting power or not.

[beast02]

I'm kinda wondering what the LED's on the megasquirt are telling me, if they don't flash when I am cranking.

"The Injector LED on the MegaSquirt lights when either Injector bank is commanded to fire, while the injector LEDs on the Stimulator light when each injector bank actually is grounded. The MegaSquirt LED will flash synchronously with the Stimulator Injector LEDs in simultaneous mode, and will flash twice as fast as either LED in alternating mode."


The injector LED's flash when on the stim...... would not getting power to the injectors make the megasquirt LED not flash??

[steamer]

I'm kinda wondering what the LED's on the megasquirt are telling me, if they don't flash when I am cranking.

"The Injector LED on the MegaSquirt lights when either Injector bank is commanded to fire, while the injector LEDs on the Stimulator light when each injector bank actually is grounded. The MegaSquirt LED will flash synchronously with the Stimulator Injector LEDs in simultaneous mode, and will flash twice as fast as either LED in alternating mode."


The injector LED's flash when on the stim...... would not getting power to the injectors make the megasquirt LED not flash??

The LED on the MS is triggered separately by the MS CPU -- there is a separate output line to light the LED. The LEDs on the stim are triggered by the injector outputs (one for each output/bank). If the LED on the MS isn't flashing when you are cranking then it is not triggering the injectors. I would hook up an confused person light in place of an injector and make sure it flashes when you crank, but based on the LED on the MS not flashing I'm guessing there is a problem with your tach input. Does the fuel pump come on when you are cranking?

With the ignition on you should see 12v at the injector terminal block on the relay board. If you are not, then there is a problem with the relay board or the wiring to it.