ECM unplugged now car will not start

[Zedscorolla]

Hello, I am new here I have an 2005 toyota corolla manual transmission. I was having some misfiring issue with and I have tried replacing the fuel injectors, ignition coils, and spark plugs and was still getting an multiple misfiring. So i "thought" maybe there is something wrong with my ECM (process of elimination) I went and unplugged my ECM and checked the continuity between the ECM to the ignition coils after I verify that it was good. I plugged the ECM back in and now the car will not start. I will crank and crank but will not start.....did I fried the ECM? not sure if it matters but the Battery was connected while I unplugged the ECM.... I ran out of ideas and clues and figure maybe someone can help me. 

[Saxmaniac]

Look at the pins and plug again to see if anything is bent or corroded and go back over anything you've disturbed, check power and grounds etc, look at fault codes and live data to see if anything missing. Wiggle test in case of bad connection or break in wiring, could just be something minor 

[Zedscorolla]

9 minutes ago, Saxmaniac said:

Look at the pins and plug again to see if anything is bent or corroded and go back over anything you've disturbed, check power and grounds etc, look at fault codes and live data to see if anything missing. Wiggle test in case of bad connection or break in wiring, could just be something minor 

I have looked at the pins on the ECM and they all looked good. No corrosion or bent pins. I also looked at the connectors to make sure nothing is bent inside or came loose after unplugging the connectors. I have also scan the car and have no codes. 

[Saxmaniac]

You probably need to work out what's missing, spark, fuel, power or grounds, you would need the circuit really 

[Mjolinor]

Big NO NO unplugging the ECU with the Battery connected.

Probably a tale of horses and barn doors but if you unplug it again make sure the Battery is disconnected before you do.

You need to investigate but my guess would be that you just scrapped your car unfortunately.

 

[Zedscorolla]

3 hours ago, Saxmaniac said:

You probably need to work out what's missing, spark, fuel, power or grounds, you would need the circuit really 

Will check that today to see if there is any spark at the ignition coil. 

[Zedscorolla]

3 hours ago, Mjolinor said:

Big NO NO unplugging the ECU with the battery connected.

Probably a tale of horses and barn doors but if you unplug it again make sure the battery is disconnected before you do.

You need to investigate but my guess would be that you just scrapped your car unfortunately.

 

Thanks for the help, should I take it to the scrap yard then? 

[Mjolinor]

2 minutes ago, Zedscorolla said:

Thanks for the help, should I take it to the scrap yard then? 

Well I would never scrap a car based on the guess from someone I didn't know. 🙂

You need to investigate the problem as stated by others.

[Mooly]

It has to be worth disconnecting the Battery now at this point and leaving it a while and then trying again. Maybe the immobiliser has flagged suspicious activity up... it has to be worth trying.

[Zedscorolla]

26 minutes ago, Mooly said:

It has to be worth disconnecting the battery now at this point and leaving it a while and then trying again. Maybe the immobiliser has flagged suspicious activity up... it has to be worth trying.

Thanks I will try this out before checking to see if I have any sparks. I do know that the car is getting fuel because I can smell the fuel when attempting to start the car.

[Zedscorolla]

I went back into the garage and tracked what I have touched the other day. I went to the first thing I mess with and remembering that I was trying to see what the wires from the ignition coil was going into. Well it look like I have a broken ground wire to the ignition coils. The wires insulations are so dried rotted and it broke off without me noticing it. I have not tried to reconnect it because I don't have any wires in the garage to reconnect the ground. I do not want to mess with it as of now I might just break more wires off...I hope this is the issue but will grab some wires from work tomorrow and fix it. 

[Mooly]

Well that looks more hopeful.

[Saxmaniac]

When you have a fault immediately after disturbing something, that's the place to focus on so looks like you're making progress! 

[Zedscorolla]

Alright I was able to get in the garage and fix it. It was the grounding was causing the ignition coil to not spark or start the car. Grab some wires and splice where the ground wires was brittle and broke off. Solder new wires for a four ground wires and clamp it with some new lugs blot the ground wires back on and it started right up. Not only it started right up the multiple misfiring also went away. no check engine light. Car drives flawless now. 

[Mjolinor]

Good news that, well done. 🙂

You were lucky not to damage anything unplugging with the Battery connected. One to store in the old grey matter.

[Mooly]

Excellent news.