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‘06 BF200 Knock Sensor #23

P

Phaze

Member
Will try to keep this short as possible and TYIA for any help!

Starting issue:
disconnected water hose behind VST due to corroded clamp. Water was obviously spraying throughout the lower cowling and I probably took it out once or twice before noticing.

Work performed:
Took off intake manifold and VST. Replaced hose onto connector and replaced w SS clamps to a lot of surrounding rusted clamps. Used corrosion X to clean. Replaced HP fuel filter and O-ring as well. It was black as night.

Next Issue:
On my test run following previous work I threw codes #1 (HO2 sensor) #23 (knock sensor). Used paperclip method to get codes. Engine ran great, no limp mode.

Work performed:
Planned to do this anyway so I took off exhaust manifolds and replaced anodes, gaskets, orings, and guide seals. Took out HO2, read 13ohms (good reading?) and reinstalled. Also checked water sep on motor, no water. Reset ECM.

Current Issue:
Took out again today. No #1 code now, but #23 persists. Engine has a very slight surge near idle on occasion and I think as well at 4-5000 rpm. Took home, reset ECM, took off Intake, found sensor with my tiny hands, and unplugged and cleaned connector (no sign of corrosion). Cleaned other surrounding connectors as well and noted no wire crimps or tears. Reset ECM.

Took out second time, still throwing #23 with the same slight surges. She runs perfect but can’t get rid of this. Wondering if I did something wrong during my initial repair or something if she isn’t getting the perfect amount of fuel creating a knock or if the code went away but the HO2 is actually bad.

Thanks!
 

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Hi,
Just spitballing some ideas/ thoughts.

Those four sensors (2 oil, 1 temp and knock are all tied to harness 18 in the link below


Did you pull the common connector for that little harness (just above the number 18) and check for water in there and the harness it plugs into? They all should get hosed with contact cleaner if at all possible.

With all that water spray I would also think checking the connection for the crank sensor (item 22) and any other you can access that may have gotten wet would be a good idea too.

Hope you get it sorted and report some success.

Good luck.
 
jgmo said:
Hi,
Just spitballing some ideas/ thoughts.

Those four sensors (2 oil, 1 temp and knock are all tied to harness 18 in the link below


Did you pull the common connector for that little harness (just above the number 18) and check for water in there and the harness it plugs into? They all should get hosed with contact cleaner if at all possible.

With all that water spray I would also think checking the connection for the crank sensor (item 22) and any other you can access that may have gotten wet would be a good idea too.

Hope you get it sorted and report some success.

Good luck.
Click to expand...
Hi! Thanks for your reply.

I did check the connector above #18, I took it off that bracket and contacts were good. Sprayed it anyway with cleaner though.

I will need to see if I can find the other one that you mentioned. I even took off the injector connections and those were good too (did spray). From what I can tell I have no water intrusion in the harness but I can’t check every one behind the intake without taking off the cyl heads.

Water seemed to mostly get all over the VST. I didn’t open it up when I had it off to check it out, and the alarms only started once I reinstalled it and the intake manifold. Starting to think I should have opened it up.
 
I don't know but you might be right about opening up the VST tank. It can get pretty yucky in there.
 
jgmo said:
I don't know but you might be right about opening up the VST tank. It can get pretty yucky in there.
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IMG_2780.jpeg
Check this out. HP fuel filter O-ring. I think I saw another thread where you said they get pinched easily, or someone else. Probably leaking air into the system, not to mention my screws were not anywhere near fully torqued on the cover. Think I’m closing in on it.
 
UPDATE for anyone that may see this in the future:

New HO2 sensor in the exhaust manifold fixed the problem. I did fix the high pressure fuel filter o-ring as well but I am pretty positive the sensor was the issue.
 
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