No pulse on injectors and ignition coils. Help!!

MG0h3

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I doubt you would have an RPM signal with a faulty cps.

Sounds like you have a pinout of the ecm. Maybe you can try and back probe at the ecm connector to look for a switching signal there; rule out an issue in the harness between the ecm and the coils/inj.
 

SlipperySnake

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I doubt you would have an RPM signal with a faulty cps.

Sounds like you have a pinout of the ecm. Maybe you can try and back probe at the ecm connector to look for a switching signal there; rule out an issue in the harness between the ecm and the coils/inj.

I'm getting continuity from injector/coil pigtail to pcm harness.


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SlipperySnake

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If you're seeing RPM on the tach the ECU is receiving crank sensor pulses.

I have aeroforce gauges and can see rpm at 80-100 but tach doesn't move. I dont know how precise that is. Maybe the engine has to be at a few hundred rpm to read? Got a new ccrm gonna try it out.


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MG0h3

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I dont know where else to go man other than trying to find out where the pcm grounds to complete the coil/injector circuit.

Can you datalog while cranking?
 
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hotcobra03

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You need to download the full pc version manual..

It has full wiring.

Each ground is direct to pcm for coils and injectors. .this is circuit pcm uses to fire each 1 separate.

Also..Google modular power..it shows power and grounds needed to start when doing swaps..has color pics of connectors
 

SlipperySnake

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You need to download the full pc version manual..

It has full wiring.

Each ground is direct to pcm for coils and injectors. .this is circuit pcm uses to fire each 1 separate.

Also..Google modular power..it shows power and grounds needed to start when doing swaps..has color pics of connectors

So the weirdest thing happened yesterday. Went to mess with it, had a few wires cut at the fpdm, signal wire or something. Anyways I hooked them up and went to start it. I could smell fuel now. Almost like it was actually firing into the cylinder now. So I hit it again and it popped about 3 times and was trying to start. I tried several more times over and over. I couldn't get it to run. I removed the plugs and they're wet with fuel. Now some have more fuel on them than others. Weird thing is I'm still getting no pulse. So it's either intermittent or a loose wire somewhere. Now I can't even get it to pop again. My buddy thinks something is wrong with the programming in the pcm or the pcm itself is bad.


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MG0h3

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Well Id get whatever you have done at the FPDM corrected and wired like stock. Im surprised that stops the injectors and coils from firing but who knows.

I wouldnt go down the bad pcm path if hooking up wires that were cut for some reason made the injectors and coils fire momentarily.
 

SlipperySnake

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It's like its getting a intermittent pulse, sometimes it'll send a pulse and other times it won't. I got it to run this morning for like 3 seconds, rpm's jumped up and all, now it won't do anything. Does anyone think that lengthening the pulse wires like I did on both the injectors and ignition coils would cause this?
 

MG0h3

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No, unless the connections are so poor that the circuit cant be completed but you said you have continuity.

What happened or what did you do at the FPDM that gave you fuel and fire?
 

SlipperySnake

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No, unless the connections are so poor that the circuit cant be completed but you said you have continuity.

What happened or what did you do at the FPDM that gave you fuel and fire?

It was the green/violet, red/white. Signal and power to pump I believe. Yet now it won't do shit, no fuel pulse or anything. I'm so lost. Like why is it intermittent.


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MG0h3

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I think most people leave the FPDM when they go return. I did. I know the tune it is set to return and commanded 100% duty cycle.

If you removed it did you already get a tune for that?

Again I dont know what the ecm will/wont do if it thinks it should have a fpdc signal coming back and doesnt...or if the circuit is open.
 

SlipperySnake

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Which wire did you run off the fpdm to feed 12v to the signal for pump 1 on. I have a fore fc3 controller. 3x465lph pumps.


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