Was going to get a hair cut this morning. About a mile from my house I noticed the engine feeling sluggish or bogged down, not very responsive.

Then the check engine light came on, so I turn around and head to the house. Made it to the house, car seemed to be fine at a constant speed.

Checked the code and its 43. Electronic Spark Control module. As usual the manuals are greek to me so I hit the internet.

This appears to be most commonly a knock sensor going bad, followed by the Electronic Spark Control module.

I read somewhere the knock sensor was passenger side of the block, just in front of the starter. Could not really see when I got on the ground because I cant fit under the car unless it is on a lift.

Looked at the ESC module, visual inspection it appeared fine, no damage or melted plastic.

Started car again, Error code cleared. Car runs fine. Took it around the block and exercised my right foot a little, car responded fine.

So bottom line I think I most likely have a knock sensor going bad.

I have one ordered.

Can someone please show me a picture of a knock sensor installed on a L98 or give me a good idea of where its located ? I would like to jack up the passenger side front and get a look if I can.

Also I just flushed coolant last month, am I right in thinking the flushing may have accelerated the dying of this part.

Kinda wishing I had just replaced it when I was doing the flush

 

Always best to replace when you have it out for flushing. Torque is very important I would do the o2 sensor..s and fuel filter while under there.

 

Antfarmer2

Did not take it out for flushing. Some said take it out for best flush, others said pull the lower radiator hose. I opened the petcock , drained, refilled ran for about 10 mins, allowed to cool the drained again. Did this for a total of three times, water was really clean the 3rd drain. Then I replaced petcock and filled. Had to pack it about 6 times over the following weeks, couple or 4 ounces at a time to finally get it filled.

Anyways, lesson learned and will be flushing it again in the future and replacing the knock sensor.
What it the torque spec? I read something like 10 - 15lbs ???

Someone got a picture of one installed so I can get a better idea of where it is on the block in front of the starter.

 

Ok, this was a big help !

 

This is what the knock sensor looks like with the exhaust manifold removed and the connector unplugged. Note that there is a shield under it that attaches to a couple of oil pan bolts.

 

Thanks Cliff

I saw the shield last night, does it need to be removed or can I work around it ?
I am assuming this thing is worked on from the bottom.

 

Just FYI: If you still have issues after replacing the sensor, keep the option open for replacing the harness wire connector terminal. The terminal connection/coating has a limited capability to remain completely electrically conductive if it's plugged/unplugged too many times.

 

Does anyone know if removing that knock sensor shield and two corresponding bolts in the oil pan are going to affect oil pan gasket integrity ? am I right in assuming the knock sensor is usually removed from the bottom as opposed to removing the exhaust manifold to get to it ???

 

oh I meant to add, when I got under there yesterday to look, I saw coolant coming out the weep hole in the water pump.... YAY !!

So this has become a bigger job.
replace water pump and knock sensor. but while I'm at it it makes sense to replace the thermostat, upper and lower radiator hoses and serpentine belt.

glad this is my new hobby, no money left for the old one ;-)

 

oh I meant to add, when I got under there yesterday to look, I saw coolant coming out the weep hole in the water pump.... YAY !!

So this has become a bigger job.
replace water pump and knock sensor. but while I'm at it it makes sense to replace the thermostat, upper and lower radiator hoses and serpentine belt.

glad this is my new hobby, no money left for the old one ;-)

 

No, that should not affect the pan gasket integrity. On the other hand, I would check it after a few days just to be sure.

Good luck... GUSTO

 

I'm getting code 43 as well on my 1990 L98, and just happen to be in need of a coolant flush! LOL
I'll count myself lucky that I read this thread first.
Guess I will do a knock sensor replacement along with with the flush. (I had so much crap in my reservoir it clogged the hose to the surge tank (I have another thread about that), so yeah, time for a flush plus this bonus job!)