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BikerGirl · 08-20-2019, 05:31 AM

Chevy 8.1 on W22 chasis: threw code PO650 for knock sensor 1; I am in upstate NY and need to know if this is a severe issue; can I just replace the sensor and or wiring? the code started shortly after I filled up in western PA going through the mountains. stopped to have it read at auto parts store. seems to be driving ok. have since filled up tank with regular like I usually do. heading further north today (currently in Syracuse) for a couple days then back to Syracuse on Thurs afternoon for the weekend
any help appreciated

vettenuts · 08-20-2019, 06:46 AM

I looked up that code and I am finding it is a circuit test failure for the engine light. Are you sure of the code?

I carry a small device that plugs into the OBD II port called “BlueDriver”. Using this device, I can pull codes very quickly and it will even provide guidance on how to correct the error.

Fyrflie · 08-21-2019, 09:32 AM

If it truly is a knock sensor, you can still drive without any major issues. Your gas mileage may suffer a little but you won’t be stuck anywhere.

Replace with AC Delco knock sensors. A competent mechanic or DIYer can replace both in about ten minutes.

On a recent trip, mine kept sending a code. I kept clearing the code until I got the parts and corrected the problem.

Good luck and safe travels.

arcaguy · 08-21-2019, 09:43 AM

If it truly is a knock sensor then driving should be ok, just listen for "pinging" when putting the coach under load. If you hear pinging back off of the throttle slightly and should diminish or cease. That said don't drive forever without a working knock sensor. This sensor "hears" the engine pinging and adjust the ignition timing and possibly and possibly other ECM parameters so it no longer hears the pinging/knocking. It's an easy replacement once you find out were it is. Good luck. One more thing going up a grade in fuel may help as higher grade fuel is less susceptible to knocking, that's what octane is all about.

LETMGROW · 08-21-2019, 03:29 PM

Vettenuts is correct. Whoever told you the code you have is wrong. PO 650, has nothing to do with detonation (Knock) sensors.
As long as you don't have any driveability issues I would continue on my way. Did they clear the code after they read it?
If not you could disconnect the chassis battery(s) ground cable for a few minutes then reconnect it. This should clear the code and the check engine light will go off when the engine is running. If the light doesn't come back on and the code doesn't return I'd keep running the way you are.
Lynn

BikerGirl · 08-22-2019, 04:32 AM

thanks everyone! after starting out to drive from Syracuse to Malone, the engine light went out. I had filled up with a new tank of gas the day before and wondering if that had anything to do with it. I also got underneath and found the sensor; just tapped on it and made sure the wire was not loose; not sure if that was it or not, but about 40 miles later on 81, the light went out. will probably get some ac delco's and have the mechanic replace.

vettenuts · 08-22-2019, 06:21 AM

The light will go out if the cause of the error code has been eliminated. Some codes require a number of error free starts. Since it was eliminated with fresh fuel, you may have gotten a bad tank of fuel. I wouldn’t throw parts at it unless you have a specific diagnosis that identifies the knock sensor as the issue. I would also start with some simple things depending on the last time it was given a tune-up. I am a strong proponent of keeping the MAF clean on this motor because it can cause a lean condition and this motor works too hard to let it run lean.

LETMGROW · 08-23-2019, 05:26 AM

Quote:

Originally Posted by BikerGirl

thanks everyone! after starting out to drive from Syracuse to Malone, the engine light went out. I had filled up with a new tank of gas the day before and wondering if that had anything to do with it. I also got underneath and found the sensor; just tapped on it and made sure the wire was not loose; not sure if that was it or not, but about 40 miles later on 81, the light went out. will probably get some ac delco's and have the mechanic replace.

Just FYI, if you are coming back from Malone and connecting with RT. 81 and still have a problem, there is a shop right next to the intersection of exit 48. The business name is 'Stadium International'. They do work on Workhorse chassis RV's.
Lynn

BikerGirl · 08-26-2019, 05:26 PM

Lynn,

great to know of that shop! thanks so much. we travel up here at least 2x per year (I'm from Malone originally; still have 90% of my extended family there and Montreal area). my brother is in Contantia; not far from exit 48. thanks again, love these forums!

LETMGROW · 08-27-2019, 05:25 AM

Quote:

Originally Posted by BikerGirl

Lynn,

great to know of that shop! thanks so much. we travel up here at least 2x per year (I'm from Malone originally; still have 90% of my extended family there and Montreal area). my brother is in Contantia; not far from exit 48. thanks again, love these forums!

I sent you a PM. FYI
Lynn