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Knock sensor relocation? |
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kylem428 
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Joined: May-31-2005 Location: United States Status: Offline Points: 263 |
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 Topic: Knock sensor relocation?Posted: February-16-2023 at 8:32pm |
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Hey all,
I have a 2007 Nautique 236 with the zr6 that was rebuilt in 2021 due to a failure in one of the lines with the remote oil pump. In any case, I have approx. 40 hours on the rebuild without any real issues except pretty routinely I get a knock sensor trouble code at higher rpm’s. After borrowing then buying a techmate pro scan tool I found it was throwing The “knock sensor open or not present” error associated with codes 327 and 332. After doing some research, It is likely this error is caused by a disrupted signal to the ecm (by pinched wiring during rebuild) or faulty sensors. Trouble is they are located under the intake manifold which I really don’t want to pull apart. I know I am probably capable but for whatever reason am a little reluctant to tackle this job. With that in mind, I have found that Michigan motor sports sells a relocation kit for the ls3 motors to place the knock sensors on the outside of the block and with sensors and harness, would be a negligible cost difference compared to pulling off the intake manifold and replacing the same parts (harness, sensors). Anyone know of whether this has been done on a Marinized LS engine of this or earlier vintage and can comment on the likelihood of this solving my issues? Link to relocation kit: https://www.michiganmotorsports.com/engine-blocks-and-rotating-assemblies/engine-block-accessories/ls-gen-iii-billet-knock-sensor-relocation-brackets-ls1-lm7-lr4-lq4-ls6-l59-lq9-lm4-l33-4-8-5-3-5-7-6-0/ Harness: https://www.jegs.com/i/ICT+Billet/335/WEKN030-36/10002/-1?gclid=Cj0KCQiAxbefBhDfARIsAL4XLRq1EndeV_Kn02B-3x6QFPZroqMYCQ3y9db9PsOPpnx5Rk0QavzPTfUaAhy2EALw_wcB Sensors: https://www.michiganmotorsports.com/ls-performance-parts/gen-3-ls-knock-sensors-qty2-replaces-12589867-fits-4-8-5-3-5-7-6-0-ls1-ls6-lm7-lq4-lq9/ A guy on YouTube did this on his Chevy avalanche without issue as in trucks these sensors are known to go bad and are a pita to service. Thanks for any thoughts or discussion you can provide! Kyle |
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KENO
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Joined: June-06-2004 Location: United States Status: Offline Points: 11118 |
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Posted: February-17-2023 at 8:52am |
I think you really meant to say Gen3 and not LS3  A friend did this on a 6.0 truck engine with no issues and no codes afterwards I'd figure it's easier than the manifold removal and makes them a lot more accessible in the future if necessary. With the new harness, you'd also be replacing the wires that you think may have been pinched during the rebuild Since knock sensors are kinda mysterious things anyways, I'd imagine that there are various different part numbers for different Gen3 applications so put in the same GM part number sensor as what's in the boat engine now or at least do some more research on the sensors I'd give it a shot |
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Fl Inboards
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Joined: January-20-2008 Location: United States Status: Offline Points: 2119 |
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Posted: February-17-2023 at 10:05am |
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OK??? if you have to remove the intake...(takes about 5 min) to repair a pinched senor wire. why not just repair the wire, rout the wire correctly and put the intake back (about 5 min) on and go ski? Its been my experience that knock sensor failure has not been an issue in marine application. your 07 is an oddball setup (1 year only) anyway best let sleeping dogs lie fix your pinch and go ski..
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Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise.
1993 Shamrock "fat" 20. 2008 Nautique 196 5.0 |
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kylem428
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Joined: May-31-2005 Location: United States Status: Offline Points: 263 |
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Posted: February-17-2023 at 12:58pm |
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Jody you raise a real good point.
Should I not be as intimidated as I am about removing the intake and associated fuel delivery and spark systems? I don’t want to pull it all apart and risk causing more trouble than I have, and don’t want to have to replace a gasket, etc but if my apprehension is unjustified, maybe I’ll give it a run? Kyle |
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MrMcD
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Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3750 |
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Posted: February-17-2023 at 9:30pm |
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Just be more than careful when working over the open intake, don’t drop anything down into the heads, if you do be sure to get it out. Pistons don’t do well with dirt intrusion or parts. Have seen many pistons brake by washers or bolts dropped down a carb or intake.
Work clean, blow the area off well before starting so there is less on top to fall down as you work and you will be fine. The gaskets should even be re useable on that design engine with lo hours on it. I believe replacement wire harness is readily available unless the boat harness was modified.
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KENO
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Posted: February-19-2023 at 8:15am |
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So...........any decisions on what you want to do?
Have you tested the sensors at the wire harness connector? Why does it only happen sometimes and only at high RPM ? The manifold removal job on this engine as compared to something like your previous gt40 is quite a bit easier, you don't have to worry about draining any water out and the whole thing comes off with the injectors, fuel rail, throttle body etc as a unit. Disconnect fuel lines, linkages and wire connectors. Is it 5 minutes quick? Only Jody knows when he starts timing this job Myself, I'd start timing when the engine hatch gets lifted up to get the job started. From your old posts and issues with ProTec and gt40 engines, I'd figure you can do the manifold job with no real issues. If you do it and still have the code problem, it'll probably get kinda old doing it over and over again till you get it figured out as compared to having the external blocks for the sensors.. Do you have a manual to reference? Intake gaskets..........half of the world will say replace, half will say they can be reused |
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kylem428
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Posted: February-19-2023 at 5:18pm |
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Well now I am thinking maybe I’d try it once and do the harness and sensors with the intake off, then if for some reason that fix doesn’t solve it, see how much trouble I ran in to the first go around and go from there.
Sounds like as long as I am careful, there’s not too much trouble I can get myself in to. I think my other hesitation on this is that I had another issue where I was losing spark on the starboard side on occasion randomly and I traced it down to a bad connection in the coil harness plug where that side connects with the harness. I think it would lose ground and none of the coils on that side would drive any spark. If the boat was running and I wiggled the plug, they’d all start working again, so part of me doesnt want to mess with the harness over the intake more than I need to as a risk to causing some other gremlin to chase. The other side of this is to jump on without hesitation and any work on it will help me learn it better so I can keep fixing myself when issues pop up. Just have to talk myself in to it. Kyle |
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KENO
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Posted: February-19-2023 at 7:59pm |
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Not knowing if you have a manual or not, here's a link to SkiDim that gets you a free download of a 6.0 manual from GM not PCM
link
It's not really written for the marine 6.0 (just check out those exhaust manifolds), but it'll tell you how to get the intake manifold off and get to the knock sensors and it'll give you torque values for the sensors and the manifold bolts and anything else you might be looking for mechanically. You could get all those values from You Tube videos but it's good to back them up with a manual written by GM. The final torque for the intake manifold bolts is very low ......89 inch lbs or roughly 7.5 ft lbs since it's a composite plastic piece The knock sensors are 20 ft lbs Good luck and take your time whatever you end up doing |
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kylem428 wrote: