kirkpal1 Report post Posted June 13, 2018 Recently purchased a Allegro gas coach with an 8.1 liter GM engine. I have driven it 200 + miles and have gotten a PO332 code twice. That code is "Knock Sensor 2 Circuit Low Input Bank 2". Should I be concerned? Would a higher octane gas help? Take it to the shop? Any input would be appreciated. Share this post Link to post Share on other sites
hermanmullins Report post Posted June 13, 2018 Kirk, Welcome to the Forum. Did the coach sit for a long time without a lot of driving? Just thinking you may have some old gas. Have you tried adding a fuel conditioner? I would try adding a double of the recommended amount and drive the coach. Also just to be sure of how it was maintained I would change the fuel filter. Herman Share this post Link to post Share on other sites
dickandlois Report post Posted June 13, 2018 Krik, Welcome to the FMCA Forum ! This is some thing that should be addressed! A knock sensor tells the engine ECM when one or more of your engine's cylinders are knocking, exploding the fuel mixture that results in less power and can cause engine damage if not corrected. The sensors cost from $ 35.00 to $ 90.00 and depends on where one buys them. You need to be aware of Knock offs that get into the parts supply lines. This might be a handy link to keep on file. https://www.ultrarvproducts.com/12591312-8.1L-Knock-Sensor-Asm Rich. Share this post Link to post Share on other sites
manholt Report post Posted June 13, 2018 Krik. Welcome. What year is the coach and mileage. How long have you had it? losing a cylinder is not a good thing! Share this post Link to post Share on other sites
kirkpal1 Report post Posted June 13, 2018 15 minutes ago, manholt said: Krik. Welcome. What year is the coach and mileage. How long have you had it? losing a cylinder is not a good thing! 2003, 96,000 miles, just bought it. Unit does not seem to have been well maintained. I did have a comprssion test done as well as new spark plugs and wires when I first bought it. Share this post Link to post Share on other sites
dickandlois Report post Posted June 13, 2018 23 minutes ago, kirkpal1 said: 2003, 96,000 miles, just bought it. Unit does not seem to have been well maintained. I did have a comprssion test done as well as new spark plugs and wires when I first bought it. The Engine is just kind of getting broken in, if it has not been abused. The engine design should get you 300,000 miles or more. One of the engine designers is a shirt tall relation. When I bought a truck with the 8.1 L. Asked allot of questions. FYI, there are engines that have had Cam and Crank shaft sensor issue, so get the engine serial number and the Chassis Vin number - if there are issues they are on a recall. Rich. Share this post Link to post Share on other sites
jleamont Report post Posted June 14, 2018 23 hours ago, kirkpal1 said: Knock Sensor 2 Circuit Low Input Bank 2". The key is "Circuit Low" that tells me the ECM cannot see the sensor, its basically looking for a voltage reading from it and its not getting that data. Could be corrosion in a connector, (either at ECM, sensor or connection between) wiring between ECM and sensor, bad sensor or bad ECM. Start with checking connections, and following wiring from sensor to ECM, look for and GREEN pins or scale buildup in the connections or wires pinched or chaffed along the way. Share this post Link to post Share on other sites
kirkpal1 Report post Posted June 15, 2018 On 6/13/2018 at 9:52 AM, DickandLois said: The Engine is just kind of getting broken in, if it has not been abused. The engine design should get you 300,000 miles or more. One of the engine designers is a shirt tall relation. When I bought a truck with the 8.1 L. Asked allot of questions. FYI, there are engines that have had Cam and Crank shaft sensor issue, so get the engine serial number and the Chassis Vin number - if there are issues they are on a recall. Rich. On 6/13/2018 at 9:24 AM, kirkpal1 said: 2003, 96,000 miles, just bought it. Unit does not seem to have been well maintained. I did have a comprssion test done as well as new spark plugs and wires when I first bought it. On 6/1/2018 at 8:29 PM, DickandLois said: Kirkpal 1, Welcome to the FMCA Forum ! Your 2003 Workhorse Chassis, is it powered by a 8.1 L gas engine or a Diesel Engine? Your coach has a P-30 / 32 series chassis, built after Navstar took over the series. Rich. Evolution of the groundbreaking W20/W22 gas platforms marks the latest appearance of a Navistar MaxxForce engine on the motor home scene. This time it’s the MaxxForce™ 7, a 230 horsepower 6.4L V8 powerplant that puts out a hefty 620 lb.-ft. of torque Before one can supply any information regarding repair of the chassis one needs to know what is powering the coach. There is information available, but it needs to be filtered and pieced together from large file covering different units. Share this post Link to post Share on other sites
kirkpal1 Report post Posted June 15, 2018 Thanks to all responses. I have scheduled it for check out at the local GMC dealer next week. Share this post Link to post Share on other sites
