How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Doug Your Own Question
Doug, ASE Certified Technician
Category: Mitsubishi
Satisfied Customers: 8536
Experience:  Mitsubishi employed and Factory trained ASE certified technician
Type Your Mitsubishi Question Here...
Doug is online now
A new question is answered every 9 seconds

2007 eclipse no start, no injector pulse, no coil pulse,

Customer Question

2007 eclipse no start, no injector pulse, no coil pulse, replaced crank sensor, no change, rpm pid doesnt rise while cranking when read on my scanner.
Submitted: 4 months ago.
Category: Mitsubishi
Expert:  Doug replied 4 months ago.


When you unplug the crank sensor and measure voltage with the key on, do you have a 12V and a 5 V wire?

Customer: replied 4 months ago.
I do
Customer: replied 4 months ago.
After I installed the crank sensor, I checked power signal and ground to it an it reads fine. I put a analog DMM on the sensor harnes and it reads correctly but still no pulses or pid changes
Expert:  Doug replied 4 months ago.


So you are seeing on/off voltage (0v-5v-0v-5v) when you rotate the engine by hand and monitor the 5V wire?

Did anything recently happen with either the key (broken, replaced, different one being used than normal) or the PCM having been replaced?

Expert:  Doug replied 4 months ago.

If you haven't specifically checked that, please do so now by back probing the 5V wire and rotating the engine by hand clockwise with the key on.
If there are any special circumstances regarding the PCM or keys please let me know and we will talk about the implications there.

Customer: replied 4 months ago.
The key has been broken for a few months now, but I hadnt had any problems so far. I parked it at school like usual, after school I got in and it wouldnt start. Ill check the voltage right now
Expert:  Doug replied 4 months ago.


With regard to the key situation... make sure the "guts" are still intact and working (light flashes); if this key has a electrical failure it will cut spark/pulse.

Customer: replied 4 months ago.
Sorry for the delay, Ive been a little busy but I checked the 5v wire. Unhooked it reads 5.5v and hooked up it read .5v and as I was turning the motor by hand the readings would fluctuate. Im getting my readings from the top connector on the timing cover.My remote still works. I can open and close the door locks with it, open my trunk and set off the alarm. I tried leaving the battery unhooked for a few days, no change. Tried pushing the unlock key a bunch of times before trying to start it, no change.
Expert:  Doug replied 4 months ago.


With relation to the key.... the keyless function is completely unrelated on this model. There are two separate entities inside the key for the two functions, so operation of one doesn't really have anything to do with the other under normal circumstances. Likewise, the use of the unlock button etc doesn't affect the immobilizer.

When rotating the engine by hand, you said they fluctuated.... we want to see very swift and solid switches between 0V and 5V... did you have fractional voltages in between or erratic behavior instead of solid switching back and forth on/off?

Customer: replied 4 months ago.
Depending on how fast I moved it fluctuated. It was pretty clear though. I know theres fuel puressure while cranking and if I disconnect the ckp, the pump wont run.
Expert:  Doug replied 4 months ago.


So we most likely have good signal from the crank sensor, which means the PCM is waking up too.

You are 100% certain that you are missing both spark and injector pulse? As apart from a wiring issue the only real expectation here is going to be an immobilizer fault.

Customer: replied 4 months ago.
I put noid lights on both the coil connectors and injectors and theyre both dead. I get voltage but no pulse. How can I check an imobilizer fault? Are there any pcm pins I can check to rule out bad computer?
Expert:  Doug replied 4 months ago.

Thanks. The only things that would kill both the spark and the injector pulse would be the crank sensor... which we can fairly rule out if you have fuel pump operation, the PCM... which we can fairly rule out since it is powering up (They don't usually fail except catastrophically), a very rare wiring issue or the immobilizer.

Given that the key has been physically broken for some time, I would suspect it is going to be that. There is nothing you can do with pin testing etc to test this... this is a logic response only, there is no voltage to measure or anything like that.

You are going to need to either get your hands on a spare key if you have one to try for comparison, or more likely get it to a dealer to have a key programmed for it. That will most likely clear everything up with your symptoms. They can check to see if the key you have is authorized first (or just reprogram it, if it will allow it) to verify 100% before purchasing a new key.

Customer: replied 4 months ago.
Alright, so basically its down to the imobilizer? I used the noid light on the injectir connector and no pulse was shown. Same with the coil, but also sprayed starting fluid to see if it would hesitate, but it wont. Is there anything else I can try or test before I have it towed to the dealer?
Expert:  Doug replied 4 months ago.

If you definitely do not have spark or fuel pulse but you do have fuel pump operation while cranking, I don't see anything else to suspect here.

The immobilizer shuts down the injector pulse first, then if the engine is persistently attempted to be started it shuts down spark. This is about the only way you can lose both at one time and not lose fuel pump operation. If the crank sensor was bad you would lose fuel pump operation, as with any problem with the PCM etc.

I honestly see no other expectation here... and given the reliability of the immobilizer system, I would only expect a key failure. Nothing else goes wrong on these except the RFID chip inside the key is prone to fail.

Related Mitsubishi Questions