Knock sensor going off 502
05-26-2009, 05:28 AM
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Knock sensor going off 502
I have a 502 with a M1 Pro charger. I bought the boat about a month ago and launched in the last 10 days. Prior to launching I filled the boat (it was on empty) with 93 octane at my local Valero station. The boat ran great.
A few days later I mistakingly added 20 gallons of 89 at a local marina. I didn't read the pump label before adding. Within a short time the knock sensor began to go off. It's not a steady alarm, and goes off at different RPMS, including idle.
To try and stop the alarm from sounding I put in 3 bottles of octane boost, which for a very short time the alarm didn't go off. I then put 15 gallons of Sunoco 93 in and again the boat began to run fine with no alarm.
Yesterday I put 30 gallons of Valero 93 in and the alarm is going off again.
As I mentioned I just recently purchased the boat, and it hadn't ran in 2 years. I didn't change the plugs ---- should I?
What could be other causes? Have I damaged the engine with that little bit of 89 (I've never ran it over 3500 when the alarm sounds)? How can I fix it? Thanks for any suggestions.
A few days later I mistakingly added 20 gallons of 89 at a local marina. I didn't read the pump label before adding. Within a short time the knock sensor began to go off. It's not a steady alarm, and goes off at different RPMS, including idle.
To try and stop the alarm from sounding I put in 3 bottles of octane boost, which for a very short time the alarm didn't go off. I then put 15 gallons of Sunoco 93 in and again the boat began to run fine with no alarm.
Yesterday I put 30 gallons of Valero 93 in and the alarm is going off again.
As I mentioned I just recently purchased the boat, and it hadn't ran in 2 years. I didn't change the plugs ---- should I?
What could be other causes? Have I damaged the engine with that little bit of 89 (I've never ran it over 3500 when the alarm sounds)? How can I fix it? Thanks for any suggestions.
05-26-2009, 06:59 AM
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something else?
What else could it be? All of my gauges show normal operation: oil pressure is 60 -80, oil temp is 180-200, there is no thermostat so water tem is low, good water pressure, fuel pressure is up (I think it was 15-30). Could it be some other type of alarm?
I think the idle is set too low, when idling the boat will sometimes almost stall --- the alarm sounds for a second -- the boat goes back into full idle.
When running on open water the alarm will sound (1 or 2 quick beeps) at various RPM's. Otherwise it's running fine and there are no other sounds.
I think the idle is set too low, when idling the boat will sometimes almost stall --- the alarm sounds for a second -- the boat goes back into full idle.
When running on open water the alarm will sound (1 or 2 quick beeps) at various RPM's. Otherwise it's running fine and there are no other sounds.
05-26-2009, 08:13 AM
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Drive oil
Yes, I just serviced the drive and the resivoir is up to the full line.
Because of the alarm at idle and almost stall, I'm wondering if it could be the idle control valve? But, if that's bad would the alarm still sound when going 3000 rpm? I probably need to get someone out here to run a diagnostic
Because of the alarm at idle and almost stall, I'm wondering if it could be the idle control valve? But, if that's bad would the alarm still sound when going 3000 rpm? I probably need to get someone out here to run a diagnostic
