Jimlbrad
09-14-2010, 09:58 AM
Hello,
I have an '03 donzi with a 496 ho giving me some trouble. Idle rpms are fluctuating as the IAC sounds like it is contantly opening and closing. There is a pronounced hiss. When I give it a little gas to around 1800 rpms, the engine will surge to 1800 then it will drop to around 1400 and flucuate between 1400 and 1550 rpms. Engine will not hold a constant RPM under 2000 RPM. At WOT I've only been able to achieve 4400 rpm when I typically get around 4900. Any ideas? I have had two mechanics look at it. There are no alarms. Engine is not throwing any codes when hooked up to a scanner. Also, fuel pressure was tested and mechanic says it's within spec. Some say it could be the IAC valve, but would that necessarily cause a loss of RPM at WOT? I sprayed intake manifold, throttle body gaskets, and injectors with carb cleaner and didn't find any vacuum leaks. Anytime let off throttle to idle, there is a very loud hiss from the iac. I'm posting videos of problems below.
Any help would be appreciated.
Thanks
http://www.youtube.com/watch?v=43Q104u2EJw
http://www.youtube.com/watch?v=mlkpe9TzBko
http://www.youtube.com/watch?v=07NJ8JV3kmY
http://images.ibsrv.net/ibsrv/res/src:www.offshoreonly.com/get/forums/images/misc/progress.gif
I have an '03 donzi with a 496 ho giving me some trouble. Idle rpms are fluctuating as the IAC sounds like it is contantly opening and closing. There is a pronounced hiss. When I give it a little gas to around 1800 rpms, the engine will surge to 1800 then it will drop to around 1400 and flucuate between 1400 and 1550 rpms. Engine will not hold a constant RPM under 2000 RPM. At WOT I've only been able to achieve 4400 rpm when I typically get around 4900. Any ideas? I have had two mechanics look at it. There are no alarms. Engine is not throwing any codes when hooked up to a scanner. Also, fuel pressure was tested and mechanic says it's within spec. Some say it could be the IAC valve, but would that necessarily cause a loss of RPM at WOT? I sprayed intake manifold, throttle body gaskets, and injectors with carb cleaner and didn't find any vacuum leaks. Anytime let off throttle to idle, there is a very loud hiss from the iac. I'm posting videos of problems below.
Any help would be appreciated.
Thanks
http://www.youtube.com/watch?v=43Q104u2EJw
http://www.youtube.com/watch?v=mlkpe9TzBko
http://www.youtube.com/watch?v=07NJ8JV3kmY
http://images.ibsrv.net/ibsrv/res/src:www.offshoreonly.com/get/forums/images/misc/progress.gif