When a LS1 get hot will the ECM cut power? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**Accelo** · 07-12-2022, 04:41 PM

When a LS1 get hot will the ECM cut power?
Wondering if it's programed in or not.

**mongocanfly** · 07-12-2022, 04:55 PM

I know mine got pretty hot before I knew about the trapped air inside engine thing, it never shut off

LS short box · 07-12-2022, 04:58 PM

I've had one of my LS swaps up to 240 plus and it was still running. The relay for electric fan failed and I was caught in heavy traffic on the freeway.
Maybe post the same question over in the PCM section?

LS short box · 07-12-2022, 05:00 PM

I've had one of my LS swaps up to 240 plus and it was still running. The relay for electric fan failed and I was caught in heavy traffic on the freeway.
Maybe post the same question over in the PCM section?

**Accelo** · 07-12-2022, 05:02 PM

Yes, I found out about the trapped air long ago. On a LS it shouldn't happen with the vent lines from the top of the heads. I always leave a heater hose off till water runs from it.

Guess I need to confess or as Paul Harvey says "The rest of the story."
The reason I am asking as I left the radiator cap loose and lost water. I filled it up but it got hot. Doesn't seem to be any damage that I can identify. But it did loose power!
Only had the factory gauge, with no temp markings on it but I can say it's likely accurate. Red means too hot to drive. LOL.
LS short box, thanks for the tip, I didn't know this board had PCM section.

e015475 · 07-12-2022, 07:50 PM

I failed a water pump a few years back on a 5.3 LS and the temperature shot way up and the engine went into 'limp mode'.

I managed to get it home by letting it cool down and get out of limp mode, starting the motor and accelerating as much as traffic would allow, then switching the motor off and coasting. Was a little nerve-wracking.

Changed the pump and drove it another 60-70K miles - didn't seem to hurt it any

akdg87 · 07-13-2022, 01:50 PM

factory ECM has a modifier table that will pull timing based on coolant temp.

rodstored-72 · 07-13-2022, 02:24 PM

I am embarrassed to share how I know this... but my 2013 4.8 did not shut off when it got too hot!! it ran until it mech. "seized"... aarrrggg!!

LS short box · 07-13-2022, 04:53 PM

I should of said the PCM section on LS1tech.com Sorry about that.

**Accelo** · 07-13-2022, 08:14 PM

Even with the programing it could conceivably happen if the coolant sensor was not covered in coolant.
I know this because I have children.

If felt like software. As It only cooled down for a couple minutes and then it would start and rev fine.
If it was mechanical their would have been permanent damage to the motor. Witch their have been no indications of damage.
After it was topped off, with water, it ran well the 30 miles to home with the air-conditioning on.
Cheers

07-12-2022, 04:41 PM	#1
Accelo Senior Member Join Date: Mar 2015 Location: washington Posts: 2,296	When a LS1 get hot will the ECM cut power? When a LS1 get hot will the ECM cut power? Wondering if it's programed in or not.

07-12-2022, 04:55 PM	#2
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,670	Re: When a LS1 get hot will the ECM cut power? I know mine got pretty hot before I knew about the trapped air inside engine thing, it never shut off __________________ Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver

07-12-2022, 04:58 PM	#3
LS short box Registered User Join Date: Jun 2015 Location: Carlos MN Posts: 2,132	Re: When a LS1 get hot will the ECM cut power? I've had one of my LS swaps up to 240 plus and it was still running. The relay for electric fan failed and I was caught in heavy traffic on the freeway. Maybe post the same question over in the PCM section?

07-12-2022, 05:00 PM	#4
LS short box Registered User Join Date: Jun 2015 Location: Carlos MN Posts: 2,132	Re: When a LS1 get hot will the ECM cut power? I've had one of my LS swaps up to 240 plus and it was still running. The relay for electric fan failed and I was caught in heavy traffic on the freeway. Maybe post the same question over in the PCM section?

07-12-2022, 05:02 PM	#5
Accelo Senior Member Join Date: Mar 2015 Location: washington Posts: 2,296	Re: When a LS1 get hot will the ECM cut power? Yes, I found out about the trapped air long ago. On a LS it shouldn't happen with the vent lines from the top of the heads. I always leave a heater hose off till water runs from it. Guess I need to confess or as Paul Harvey says "The rest of the story." The reason I am asking as I left the radiator cap loose and lost water. I filled it up but it got hot. Doesn't seem to be any damage that I can identify. But it did loose power! Only had the factory gauge, with no temp markings on it but I can say it's likely accurate. Red means too hot to drive. LOL. LS short box, thanks for the tip, I didn't know this board had PCM section.

07-12-2022, 07:50 PM	#6
e015475 Registered User Join Date: Nov 2013 Location: Show Low, Arizona Posts: 778	Re: When a LS1 get hot will the ECM cut power? I failed a water pump a few years back on a 5.3 LS and the temperature shot way up and the engine went into 'limp mode'. I managed to get it home by letting it cool down and get out of limp mode, starting the motor and accelerating as much as traffic would allow, then switching the motor off and coasting. Was a little nerve-wracking. Changed the pump and drove it another 60-70K miles - didn't seem to hurt it any

07-13-2022, 01:50 PM	#7
akdg87 Registered User Join Date: Sep 2013 Location: fairbanks, ak Posts: 339	Re: When a LS1 get hot will the ECM cut power? factory ECM has a modifier table that will pull timing based on coolant temp. __________________ build thread 1955 cameo turbo lsx 1993 K1500 Blazer 5.3/4L80e 2009 CTSV Sedan

07-13-2022, 02:24 PM	#8
rodstored-72 chevy truck fan Join Date: Mar 2005 Location: Gilbert, arizona 85298 Posts: 2,008	Re: When a LS1 get hot will the ECM cut power? I am embarrassed to share how I know this... but my 2013 4.8 did not shut off when it got too hot!! it ran until it mech. "seized"... aarrrggg!!

07-13-2022, 04:53 PM	#9
LS short box Registered User Join Date: Jun 2015 Location: Carlos MN Posts: 2,132	Re: When a LS1 get hot will the ECM cut power? I should of said the PCM section on LS1tech.com Sorry about that.

07-13-2022, 08:14 PM	#10
Accelo Senior Member Join Date: Mar 2015 Location: washington Posts: 2,296	Re: When a LS1 get hot will the ECM cut power? Even with the programing it could conceivably happen if the coolant sensor was not covered in coolant. I know this because I have children. If felt like software. As It only cooled down for a couple minutes and then it would start and rev fine. If it was mechanical their would have been permanent damage to the motor. Witch their have been no indications of damage. After it was topped off, with water, it ran well the 30 miles to home with the air-conditioning on. Cheers Last edited by Accelo; 07-13-2022 at 11:03 PM.

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