high idle/check engine light

[gride300]

everything on my boat is working fine. however, when i idle sometimes it goes up to like 1300rpms, i pull it to neutral and they slowly go down, then it will idle fine. it happens randomly. also, sometimes when i start the boat the check engine light will stay lit, but if i hit stop, then start it again it goes off. i noticed the key on the prop is slightly worn, but not spurring on each end. i was gonna replace it but the new key is shorter and does not have the little pole to hold it in place so i didnt know if i could use it. thanks for the help. i just had the throttle cable checked along w/ just about everything else.

[JUST-IN-TIME]

RE: high idle/check engine light

what motor and boat?

[AirTool]

Re: high idle/check engine light

i was gonna replace it but the new key is shorter and does not have the little pole to hold it in place so i didnt know if i could use it.

Fact - a shorter key is okay

Opinion - if you are using that stainless steel key with the index pin, switch it out for a soft brass key that might shear upon impact and reduce the chance of damaging your shaft. No guarantee.

AirTool

[gride300]

RE: Re: high idle/check engine light

im going to take the prop off next week when i get it on the trailer, check for hi spots on the shaft, then put the new brass key in, clean w/ scotch brite, etc. basically what it says to do on the correct craft fan thread. i'm sending my 1464 acme to them to get the dings out. its a great prop for me b/c w/ 2700lbs +/- it runs at about 3200rpms and gets out of the hole in 1 second, but w/ no weight in the boat it runs about the same rpms and tops out at around 32. i think going to leave the oem prop on for a while.

[j2nh]

Re: high idle/check engine light

everything on my boat is working fine. however, when i idle sometimes it goes up to like 1300rpms, i pull it to neutral and they slowly go down, then it will idle fine. it happens randomly. also, sometimes when i start the boat the check engine light will stay lit, but if i hit stop, then start it again it goes off. i noticed the key on the prop is slightly worn, but not spurring on each end. i was gonna replace it but the new key is shorter and does not have the little pole to hold it in place so i didnt know if i could use it. thanks for the help. i just had the throttle cable checked along w/ just about everything else.

What engine?

[gride300]

RE: Re: high idle/check engine light

ex330.

[DanielC]

RE: Re: high idle/check engine light

Idle speed in a modern fuel injection motor is not controlled by the throttle plate. There is a bypass passage controlled by a motor that controls the amount of opening in the bypass, and this motor is controlled by the engine computer.
You might want to check to see if any vacuum hoses have come off, or disconnected, that will also allow extra air into the manifold, and cause your idle to go high.
Sorry I cannot help more, I am more "in tune" with GT-40 motors.
The "check engine" light means there is a very good chance the engine has a diagnostic code set. Your dealer should be able to pull the code.

[gride300]

RE: Re: high idle/check engine light

no that sounds right b/c i had this issue once and my guy said it was a hose. if i remember this thread whenever i get it fixed i'll update ya'll on what the issue was.

[j2nh]

Our club 330 ex has a similar issue and we were told it was the Throttle Actuator Control (TAC) module. Ours will be going in to the shop in a month, when the ice is gone, and will pass along what they find.

[Quinner]

I have had an issue of high idle with my 05' Excal since day one, been to the dealer twice w/o resolution, gave up and fixed it myself.
Mine seems to be related to the throttle cable and the shroud. Tried messing with the cable routing, no change - shimmed the back side of the shroud to ensure it is not touching the throttle cable, no change - removed the shroud, problem solved.
Would be nice to have a "real" fix, just not sure what it is, been running without the shroud since new.

[CraigH]

I have had a similar problem and have somewhat narrowed it down to the idle control valve, which may well be the same as the TAC module. When I have the problem, you can just hear a ton of air being pulled through the housing. On my last run of the year I unplugged the module and the boat ran OK, and it temporarily fixed the problem (which makes me wonder what the specific purpose of the thing is). The dealer I bought it from said it wouldnt hurt anything to run it without the module connected for a while and said I could just go to any auto parts store and get an idle air control valve for a 1999 or older Vortec 5.7L engine. It is about a $65 part and I plan on changing it out to see if it fixes the problem when I pull the boat out for the spring.

[gride300]

i'll mention the TAC to my guy in a couple weeks and removal of the shroud and post back

[j2nh]

I have had an issue of high idle with my 05' Excal since day one, been to the dealer twice w/o resolution, gave up and fixed it myself.
Mine seems to be related to the throttle cable and the shroud. Tried messing with the cable routing, no change - shimmed the back side of the shroud to ensure it is not touching the throttle cable, no change - removed the shroud, problem solved.
Would be nice to have a "real" fix, just not sure what it is, been running without the shroud since new.

Weird. We did the same thing with our club boat in order to finish out the season. No interference so I figured it was an inadequate ventilation for the TAC module. Still happened with the shroud off, just not as frequently.

[DavidF]

Is the TAC and ICV the same thing? To me, the TAC is only on boats with "drive by wire" and the ICV is on boats with a conventional throttle cable. Both are computer controlled.

I am not too familiar with the TAC, but I think it serves two purposes: idle control and throttle control. The ICV' only purpose is to control idle by bypassing air around the throttle plate. The ICV is computer controlled via RPM signal input. So, the ICV can compensate for small vacuum leaks as the computer will keeping trying to adjust to a preset RPM. However, the adjustment capability is finite and if the vacuum leak is too large, the ICV cannot maintain RPM and goes out of range and throughs a check engine light and sets a code. I guess.

[j2nh]

gride300 did you ever find the cause of the problem?