Will not stay running after tightening the battery up and went down too far and bridged positive on battery to ECU

1997 MITSUBISHI ECLIPSE

187,000 MILES • 2.0L • 4 CYL • 2WD • AUTOMATIC

YABOIFISHIE

MEMBER
3 POSTS

Last year, I bought stock headlights for my car as the aftermarkets were dim and hazy. I was taking them out and the driver's side, whoever had the car before me, cut the factory headlight clip off and direct wired. So temporarily I was going to do the same until I got my clip ordered in. Well, I disconnected the battery, so I didn't short anything out. I got done, started tightening the battery up and went down too far and bridged positive on battery to ECU. Sparked and everything. Went to go turn it on, it would start for a few seconds and shut off. I've replaced the ECU, I've used my multi meter and checked coil pack, I've checked cam sensor, fuel injector sensors. I have no idea as to why it will start for a second, bog, and shut off. Please help. I've been trying to get this thing fixed for a while.

May 5, 2022 at 8:57 AM

KASEKENNY

✓Experienced Mechanic
18,907 POSTS

Just to be clear, you touched the wrench to the case of the ECU and that is what caused the sparks?

If that is the case, then that would most likely not cause any issues with it as the voltage is just passing directly to the frame and ground.

So, if the engine starts and stalls then we need to make sure the theft light is not remaining on.

I would suggest we start with checking the vehicle for codes and find out if there are any that will point us in the right direction.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Also, I am attaching the info below from the manual that will talk about this.

Let's make sure the light is out and we can go from there.

Thanks

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May 6, 2022 at 7:41 AM

STRAILER

✓Experienced Mechanic
55,273 POSTS

You could have shorted out the IAC. To be sure let's run the codes to see what comes up, here is a guide to help:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

In case this is the problem here is how to change out the IAC motor. Check out the diagrams (below). Let us know what happens and please upload pictures or videos of the problem.

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May 6, 2022 at 7:44 AM

YABOIFISHIE

MEMBER
3 POSTS

Kenny K, it touched the ECU. It got it pretty good. I ran codes, but nothing came up. Here's what it does. (posting a link to YouTube video.) https://youtu.be/qbKiikhlKpA

May 6, 2022 at 9:25 AM

YABOIFISHIE

MEMBER
3 POSTS

Ken L, I'll need to check into that. The IAC. No codes came up. When I had my old ECU, I used to not have a gas light, and when I installed my new ECU in, I have lights I've never seen on it, haha. But yes, no codes had come up. Here's a video. If you need a better video let me know.

https://youtu.be/qbKiikhlKpA

May 6, 2022 at 9:29 AM

KASEKENNY

✓Experienced Mechanic
18,907 POSTS

Okay. Based on these videos, which does not seem like an IAC issue even though I that that was it when Ken mentioned it.

This seems like a fuel issue so let's do two things. First, we need to use stater fluid in the intake and see if the engine fires and runs longer than it is.

Next, we need to check the fuel pressure to confirm this issue.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Let me know what you find with this, and we can go from there.

Thanks

May 6, 2022 at 11:43 AM

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