2003 buick v6 cuts off at 155 degrees?

sotxbill · May 1, 2019

2003 buick la sabre 3.8 v6... engine shuts off when temp gets to 155 degrees...

Good fuel pressure at 46 lbs running and jumps to 50lbs when it cuts off... Starts and runs perfect cold, and warms up to 155 and then its like you turned off the key. Let cool down and repeat again... Its grandma's car so only has 87000. No codes or lights on the dash so thats useless.

cleaned throttle body and inspected idle control, egr is clean and free so its not sticking..

suspect crank shaft sensor next, ignition control module after that? Something else telling the ecu to cut off?? temp gauge and electronic temp on display both working correctly.

anyone got and ideals?

steve_in_mo · May 1, 2019

Bad temp sensor or bad ecu.
Temp sensor is (usually) a separate unit from the thermostat.

David G · May 1, 2019

Any stored codes?

Ronnie Budd · May 1, 2019

A different car, but my son had a Pontiac Firebird with the Chevrolet V8 that would do that exact same thing. It turned out to be the coil.

JMOR · May 1, 2019

Some engines have two temperature sensors . One for feeding gauge/Hot indicator light AND a separate one feeding the ECM.

David G · May 1, 2019

Sorry, did not see post about codes.

My bet would be on crank sensor, spray it with Freon and see if it works after stopping.

sotxbill · May 1, 2019

Does anyone know where the second temperature sensor is located? As the heat gauge and digital readout on the dash both agree, I need to find the second sender??

Side note, didnt the 3.8 first appear in the buick line up? They have had several buicks and all had the 3.8, and all got very good mpg and service. I incorrectly assumed buick had it first??

And thanks for the responses...

David G · May 1, 2019

I really doubt a temperature sensor would stop the engine.

If you have a scanner, go in and view the live data.

Sprint 6 · May 1, 2019

When it stalls, unplug the Mass Air Flow
sensor on top of the throttle body. If it
restarts right away, the Mass Air Flow
sensor is bad. See this a lot with the
3800, only happens warm, the MAF goes to 0,
so the computer says no fuel.

Michael Soldan · May 1, 2019

Agree ! MAF can also be dirty , a can of MAF cleaner and some patience and the problem could be fixed.

David G · May 1, 2019

I agree, it is something that totally fails, like crank or MAF sensor.

JMOR · May 1, 2019

(quoted from post at 12:15:50 05/01/19) I really doubt a temperature sensor would stop the engine.

If you have a scanner, go in and view the live data.

oubt no longer, as it sure will on a 1992 TBI 5.7 Chevy truck!

Sprint 6 · May 1, 2019

Coolant temp sensor will kill a GM TBI
truck dead. Just had one in the shop like
that last week.

Bob · May 1, 2019

When it quits, check for spark with a spark tester and injector "power" with a "noid lite", to see check fails, or possibly both.

rlp in Co. · May 1, 2019

Great suggestion! I didn't know an engine would run with that unhooked. This is why I love this site.

sotxbill · May 1, 2019

(quoted from post at 11:44:19 05/01/19) Agree ! MAF can also be dirty , a can of MAF cleaner and some patience and the problem could be fixed.

maf is clean, ie the varistors are white and the leads are silver, so no cleaning needed... upon previous inspection.....

but it still could be bad so I will try to pull that connector off when it dies.... and see what happens... Maybe I can get it to at least throw a code.

Thanks.

waiting for the harmonic balance puller to come in.. Someone borrowed mine and didnt bring it back.

4play · May 1, 2019

(quoted from post at 10:57:44 05/01/19) Does anyone know where the second temperature sensor is located? As the heat gauge and digital readout on the dash both agree, I need to find the second sender??

Side note, didnt the 3.8 first appear in the buick line up? They have had several buicks and all had the 3.8, and all got very good mpg and service. I incorrectly assumed buick had it first??

And thanks for the responses...

There is just one temp sensor. It is located on the back of the cylinder head right under the thermostat housing.

The "Buick V6" engine family started in 1962, it went through a bunch of sizes, variations and series, they even sold the design to AMC ('67-'74ish) then bought it back. The final 3800 series III began in 2003.

Super H Mike · May 1, 2019

The temp is so specific at the failure point that I would be looking at the coolant temp sensor also. If it goes open or shorts could make it die out. I would think you could restart it though, and it would likely run poorly after the restart. Crank sensor maybe, but I would think it would need to be hotter to fail that, and would be more random or variable IMHO. It will run pretty much normal with the MAF sensor unplugged so I would run it through a warm up cycle with it unplugged. Also you can tap on the MAF and tug on the wires and watch for stumbles. Some have the IAT integrated into the MAF also so I would watch that reading also just for the heck of it, although I cant see that alone stalling her out, but could point you to a bad MAF. That is , if it isn't separate like in the air cleaner housing. A good scan tool should be able to catch what is happening. I had an 06 Buick once that was cutting out like that, that one was the PCM, likely bad solder joints . But that one wasn't as predictable like you said this one is at 155 degrees.

SDE · May 2, 2019

My old truck did that. It was the temp sensor.

2003 buick v6 cuts off at 155 degrees?

sotxbill

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steve_in_mo

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David G

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Ronnie Budd

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JMOR

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David G

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sotxbill

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David G

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Sprint 6

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Michael Soldan

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David G

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JMOR

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Sprint 6

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Bob

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rlp in Co.

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sotxbill

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4play

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Super H Mike

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SDE

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