persistent knock sensor code-kind of fixed?

[RickHaleParker]

If you think it maybe carbon build up.

1. Pull the Spark plugs.
2. Pour some Seafoam additive in each cylinder to flood the top of each piston.
3. Stuff rags down each Spark plug well.
4. Let sit overnight.
5. Crank engine to push out any liquid Seafoam.
6. Reinstall spark plugs.
7. Start engine and let it idle until it stops blowing black carbon out the tail pipe.
8. Drive the car until a hard acceleration no longer blows black carbon out the tail pipe.

Notes: If the cylinders are as bad as suspected, expect thick black smoke out of the exhaust. It can take 20, 30 .. 45 + minutes of idling for the carbon to clear up.

If you want to get the Combustion chambers free of carbon also. Remove the Cam cover which will close all the valves. Then in step #2 flood the cylinders to the bottom Spark plug threads. After step #4. Reinstall Cam cover the do steps 5-8.

Modified procedure to clean Combustion chambers also.
1. Pull the Spark plugs.
2. Remove Cam cover.
3. Pour some Seafoam additive flooding the cylinders to the bottom Spark plug threads. .
4. Stuff rags down each Spark plug well.
5. Let sit overnight.
6. Reinstall Cam cover, timing engine in the process.
7. Crank engine to push out any liquid Seafoam.
8. Reinstall spark plugs.
9. Start engine and let it idle until it stops blowing black carbon out the tail pipe.
10. Drive the car until a hard acceleration no longer blows black carbon out the tail pipe.

[darrylrobert]

i noticed the Knock sensor codes after getting VIDA 2 years ago, my expensive hand held scantool (icarsoft) doesnt show the knock sensor code so i have been unaware for the 4 years ive had the car. I bought the car cheap because it had zero paperwork, after the dealer warranty period ended.

I have been very interested in this "seafoam" stuff, some very good reviews on it but also some bad reviews. Volvo recommend not to use any additives on their engines, and I worry about it eating away at the piston rings.

[abscate]

It’s just a collection of solvents and organic chemicals. It won’t attack metal on the short timeframe of an overnight soak

You need quite a bit to cover the piston tops as I found during my cylinder head job, the pistons are angled back to the rear, or right side of the engine , so liquids will pool there.

[RickHaleParker]

I worry about it eating away at the piston rings.

If it ate metal Seafoam would be long gone and buried under all the lawsuits for damages.
Seafoam is Pale oil, Naphtha, and Isopropyl Alcohol (IPA).

Seafoam eats the Carbon on the rings not the rings. If a engine is so far gone the Carbon is the only thing holding it together. It would start burning oil after a Seafoam treatment. Sound like you been reading postings from idiots that screw up then blame others.

[abscate]

MVS LEGAL DEPARTMENT

IPA is not beer.

[RickHaleParker]

MVS LEGAL DEPARTMENT

IPA is not beer.

Beer is unadulterated Ethanol alcohol.

At a Ethanol fuel plant they are required to adulterated the Ethanol alcohol so people will not drink it. The adulteration is Methanol alcohol, which can cause irreversible neurological damage, blindness and death.

[erikv11]

MVS LEGAL DEPARTMENT

IPA is not beer.

Loved this one

[darrylrobert]

Do these numbers look okay? is a STFT 0.78% mean its leaning out?

rear knock sensor code

rear knock sensor 12feb2021.jpg (139.56 KiB) Viewed 1091 times

[abscate]

O.78% STFT is excellent. It means the ECU is well within bounds of normal adjustment

The error code for out of bounds happens at about 20% fuel trim

[darrylrobert]

ok thanks, what about the mass air flow number?

hows this for weird..i placed the rear sensor back to its normal position 3 with copper washers and i got the "knock code" moved it back to position 2 and no "knock code"??

rear knock sensor location change

volvo knock sensor locations a.jpg (202.08 KiB) Viewed 1089 times