Car won’t start. Need help!!

[mk2davis]

Keep us informed about progress.

 

[GVR41380]

You need to ensure the ECU isn't damaged as @gvr4ever points out- If the caps are bad it explains a lot.

That said, I've seen a CAS go bad before where it was fine until the car warmed up and then it started reporting extremely erratic data (i.e. 11k+ RPM at idle, etc). I would not replace it until you get into the ECU and confirm what's actually wrong.

If the ISC driver on the ECU is smoked (also possible given the symptoms), don't plug the ecu in after getting it repaired until you verify the ISC isn't bad. I've had the FIAV leak into the ISC, short it, and kill two ECUs in a row before I checked, you don't want that evil on you

How do I make sure the ISC is not bad? You’re talking about the ISC on the throttle body correct? Or do you mean the ISC driver inside the ECU?

 

[mk2davis]

This might help? https://www.dsmtuners.com/threads/bad-isc-destroying-ecu.269343/

 

[GVR41380]

This might help? https://www.dsmtuners.com/threads/bad-isc-destroying-ecu.269343/

This helped a lot thank you so much!!

 

[GVR41380]

Here is a picture of the ecu that was in my car. The caps look good but I can’t tell what I’m looking at for the drivers part. Maybe someone can see something I don’t.

 

[GVR41380]

Here is a picture of the ecu that was in my car. The caps look good but I can’t tell what I’m looking at for the drivers part. Maybe someone can see something I don’t.

View attachment 3032

View attachment 3033

Here is the underside of the ECU board

 

[mk2davis]

I don't think it's the problem, but both sides of that board seem a bit unclean. Maybe a paint brush; I don't know what if any chemicals to use?

 

[GVR41380]

I found a spare ISC Sensor that I had in my parts pile, don't know if it's good or bad, so anyway I took off the one that was on the car and swapped in the other ISC, and yet again the car will start up for a brief couple of seconds and then stall off, like the fuel just shuts off. Then I unplugged the ISC from the connector and same thing happens. so im just not going to mess with the car until i get the new ECMLink Cable in the mail, should be here on Wednesday the 7th. Until then I will post what I gather with the data from DSM Link.

 

[mk2davis]

And?

 

[Imback]

Just seen this.It sounds like a dead MAP sensor or a fuel pump issue

 

[GVR41380]

Just seen this.It sounds like a dead MAP sensor or a fuel pump issue

I’ve changed the map sensor and the fuel pump is only 2 years old, it’s a walbro 525 Hellcat with the require kit, I’ve gone through the wires on the fuel pump and the relay is new and I checked and cleaned the grounds so still at a lost, I should have the new ECM link cable today fingers crossed that I can get more data from Link when it arrives today, stay tuned

 

[GVR41380]

Okay so today the new cable came in and I plugged it in and it works! Well the cable works and I can now log and look into the ECU, but seems like my tune is gone and the ecu some how reset itself. So now I’m going to try and learn how to use ecmLink. I got the car started up and my wideband was reading 7 so I turned it off I’m smelling a bunch of fuel, I am going to need help configuring the ecu inputs. Anyone here know anything about dsmlink for speed density??

 

[turbofonz]

So if your tune is gone, that's also likely why the car doesn't run. Between SD not being setup , injectors not scaled correctly, etc.. it's not gonna run

 

[Imback]

The ecu resets when you try to start it with low voltage. I would go on the ecmlink forums and also there wiki has a simple rundown of how it works. If you don't want to wait you can just have someone remote tune it for you.

 

[GVR41380]

The ecu resets when you try to start it with low voltage. I would go on the ecmlink forums and also there wiki has a simple rundown of how it works. If you don't want to wait you can just have someone remote tune it for you.

This makes sense. I tried to start the car with an almost dead battery a month ago, so I then bought a new battery, I reached out to my tuner who tuned my car back in 2020. Thanks for this information I would of never guessed that.

 

[GVR41380]

Okay so I got into Link on the laptop and I scaled the injectors and set up the correct size injectors and now the car runs great! Thanks for all the help guys really appreciate it!

 

[gvr4ever]

Just curious... How far off were the injectors? I'd thought it would either run rich or lean, but I wouldn't have thought, not at all.

 

[GVR41380]

The injector size was at 450 I believe before I had to change them, the car was running really lean to the point where it would start and stay running for about 3 seconds tops.