Community Forums

kirkpal1 · 04-18-2019, 07:59 AM

2003 W22 8.1 L
Purchased the unit used with 95k miles. Had engine checked out, compression etc. First trip I got a check engine light, ran the code reader, Knock Sensor code. Took to shop, mech found bad wiring to Sensor, repaired. Next trip got same code, mechanic said heat shield missing causing over heat of sensor, installed shield. Next trip got same code, changed sensor. Next trip got same code?? Help

Arch Hoagland · 04-18-2019, 09:33 AM

Do you remember the actual code number?

Duner · 04-19-2019, 12:28 AM

Check the exhaust pipe doughnut for any hot & loud exhaust leakage. The exhaust pipe junction and knock sensor are very close together.
I got the code, changed both knock sensors and then found out it was picking up the noise or heat from hot exhaust.

Good luck,
Bill

kirkpal1 · 04-19-2019, 03:18 PM

Cannot remember exact code right now. Son is using the coach now and all my notes are with him.

kirkpal1 · 04-26-2019, 08:06 AM

Code is Po332 Knock Sensor 2 Circuit Low Input (Bank2)

Summery:
*Purchased used at 95k miles.
*First use received code Po332
*Unit to GMC dealer, found the sensor cracked and wiring damaged. Replaced wiring and sensor.
*Next use got code Po332, returned to GMC dealer, mechanic said heat shield missing, overheat giving code. Replaced heat shield, wrapped wiring with foil tape. Not many miles down the road got the same code again.
*Personally inspected the sensor, wiring ok, sensor not broken. Checked for exhaust leaks at manifold and doughnut. None found.
*next use, got code P0332, ran tank near empty, filled with 91 octane gas, ran tank near empty again and refilled with 91 octane. Cleared the code and make another trip, less than an hour into the trip at 2100 RPM received the code.

The question now is after putting over 7000 miles since purchase and consistently getting code, Do I really care anymore? Should I just bypass this signal and move on?

Arch Hoagland · 04-26-2019, 09:52 AM

Good question, don't know what the long term effects are. Perhaps some other knowledgeable people could reply.

PJStough · 04-26-2019, 09:58 AM

Could it be piston slap? It has been known to occur in the GM 8.1 engine.

Duner · 04-26-2019, 10:08 AM

Give Jon Brazel a call at 877-786-1576.

They have helped me on Workhorse issues for 13 yrs. Brazel's RV Performance is one of the iRV2 sponsors and have a lot of experience with 8.1L engine.

Good luck,
Bill

vettenuts · 04-27-2019, 07:55 AM

A lean condition can throw that code, I would personally clean the MAF and if you haven’t replaced the air filter recently install a new filter to see if that clears the code.

Also verify your engine temperature.

Kickman921 · 04-30-2019, 04:28 PM

Quote:

Originally Posted by kirkpal1

2003 W22 8.1 L
Purchased the unit used with 95k miles. Had engine checked out, compression etc. First trip I got a check engine light, ran the code reader, Knock Sensor code. Took to shop, mech found bad wiring to Sensor, repaired. Next trip got same code, mechanic said heat shield missing causing over heat of sensor, installed shield. Next trip got same code, changed sensor. Next trip got same code?? Help

I also have a 2005 w22 with 8.1. For the last 20k miles I have dealt with this condition. It tends to exhibit itself after a hard start, mechanic suggests high octane as a solution. He checked sensor can find anything wrong with it. But I tend to think it has problems with the harness, maybe you are on to something with the heat impact. Looking forward to more input.

I always clear fault code and move on.

ClassyC · 04-30-2019, 04:38 PM

Agree with cleaning MAP sensor, make sure you get a can of something acceptable for that (not carb cleaner). I went thru this on my Toyota pickup, the web told me my particular sensor was bulletproof (and a pain to change). I ended up putting several cans of fuel treatment thru the engine and it went away for the last year...Good luck. Oh yeah, the web did mention that mice chewing on wiring were another intermittent cause, mine were fine.

daw106 · 05-06-2019, 12:21 PM

On my way home from a big RV center for oil and filter change, I saw my check engine light on. I checked the code out and it is for my anti knock engine sensor on the 8.1 L GM gas engine. I drove over 2600 miles last summer and never had a problem until I brought the RV in for the oil change. getting ready for the summer road trip and this makes me nervous. Rather new to RV'ing. Where is the exhaust manifold port and doughnut located on the engine? Just starting to get familiar with this RV.

Massanutten · 06-17-2019, 05:47 PM

I had the same problem for 10,000 plus miles I have a new rebuilt Jasper engine it drives me crazy to have a light on . I had three different shops try and fix. I just clear codes and carry on. I am sure this has an answer but I have not been able to find it.

Duner · 06-17-2019, 07:16 PM

Quote:

Originally Posted by Massanutten

I had the same problem for 10,000 plus miles I have a new rebuilt Jasper engine it drives me crazy to have a light on . I had three different shops try and fix. I just clear codes and carry on. I am sure this has an answer but I have not been able to find it.

Try running a couple tanks of premium gas and see if the pinging and the code goes away. I have a Jasper engine too and can hear pinging at some throttle positions, rpms, and load. I've run two tanks of premium and the 8.1 seems to like it really well. My MAF readings are always low, like 215 to 220 g/s max at WOT. I've replaced the MAF twice and had shop check for vacuum leaks to get the MAF readings up to 230 or more at WOT.