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95 454 tbi high idle engine light

n36511

n36511

Regular Contributor
I have a 95 carver with twin 454 tbi's and the starboard engine idles high and the check engine light is on. This situation occurs 5 out of 6 times I crank the engine....cold or hot. I have verified that the butterfly's are fully closed and have replaced the iacv. No change. Any thoughts on next steps? I think there is water in the fuel but didn't think it would cause high idle. I change the fuel water sep every 10 hours or so.

Thanks for the help!!!!!!
scott
 
Ok I will give that a try. Thanks! One question.... can bad fuel cause the engine light to come on like that and cause high idle? I ask because I know I have some crappy fuel in the tank but not sure if it could actually cause these symptoms.

Thanks,
Scott
 
If the check engine light is on, it is best to get a scan tool and find out why. the computer turns the light on when something is not as expected and it usually isn't too hard to find the 'bad item'.

Bad fuel is best removed...given the simplicity of the ECUs in that vintage, i would say bad fuel isn't likely to be the cause of the the check engine light coming on but is high on the list if the engine's performance is suffering.

Did you check to ensure the TBI is fastened securely?
 
Thanks for the tip. I did not check the TBI but will do that next trip to the boat. I asked the marina to read the code and let me know what it is. I will post my findings.

Thanks again
 
That would be most helpful.

Factory data also suggests the TPS, its reference voltage supply, or its ground could also be contributors to a high idle .
 
Wanted to circle back and provide update for those who end up searching for fixes for same issue. Had mechanic come by with code reader. It immediatedly picked up on TPS (throttle position sensor) errors. Engine was not getting right reading back from TPS so it would advance throttle until it received the right voltage reading. TPS repaced and issue is now gone. Thanks guys for helping me out and pointing me in the right direction!!
 
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