95 lesabre knock sensor

[LiqiuidWrench]

Hello All,
Would someone kindly tell me where the knock sensor is located on a 1995 Buick Lesabre? It has a 3800 engine, if you have a picture or diagram to show where to locate it I would GREATLY appreciate it.

Thanks in advance for your help!

[HotZ28]

The knock sensor is mounted in the center, back (firewall) side of the block. You can only access it from the bottom of the engine. What is the problem with the knock sensor?

[m_schroeder]

I had a knocking / pinging problem (noisy) when trying to accelerate hard up hills or when on the freeway at 60-70. It was a two port bottle shaped check valve located next to the vacuum tree that was drianing down the rest of the vacuum system and really screwing up performance and other things. For a $5 dollar part available as a simple "HELP" part on the shelves of most auto stores, this is highly recommended as a first step for many engine problems. My next recommendation is to clean the mass air flow sensor - MAF or replace it.

[LiqiuidWrench]

Originally Posted by HotZ28

The knock sensor is mounted in the center, back (firewall) side of the block. You can only to access it is from the bottom of the engine. What is the problem with the knock sensor?

I bought this car from a little old lady who only drove it to church on Sundays, LOL. The car has 210,000 miles on it, the check engine light came on, I ran a scan and it said that the knock sensor was the problem. The car has very little power upon acceleration but once you get going it is normal. I thought I would also run a vacuum check to make sure it is not a vacuum leak.

[HotZ28]

Can you here any 'pinging' sound coming from the engine under load & light acceleration? BTW, the "little old lady" must have lived a long ways from her church to put 210K miles on the car!

[LiqiuidWrench]

There is no pinging at all under a load when the engine is cold or hot
when the engine is cold you have good acceleration but when the engine gets to operating temperature and you take off from a stop light it is very sluggish until you pick up speed Its like the ecm is retarding the est

[HotZ28]

It sounds like the knock sensor is retarding the timing as it should. This will happen if the sensor actually hears knock, or if the sensor is giving a false feedback to the PCM. You could have a bad knock sensor or a real ping, but to faint for you to here. You can replace the sensor, but you may also have carbon build-up in the combustion chamber giving real evidence of a knock! Good Luck!

[m_schroeder]

Liquid Wrench,

just want to mention, I had about the same exact problems. I suggest checking/replacing the two-way check valve in the vacuum line (HELP! part number 47150) and cleaning the MAF sensor.

[LiqiuidWrench]

Thanks! M Schroeder & Hotz28,
I greatly appreciate your help on my problem, I will check the 2 way check valve in the vacuum line and clean the MAF sensor. This is a good place to start, if that does not help I will check connections on the knock sensor and replace if necessary.