Merc 496 GURU Question
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Merc 496 GURU Question
The intake manifold air temperature (IAT) via the PCM555 ECU I have observed seems to track engine temperature and to be almost non responsive to the intake air temperature to include the fact that the IAT continues to rise to its steady state soak temperature regardless if the engine is idleing or running at WOT. I am told that this is not the case with IAT from outer intake manifold systems which typically show a significant drop in IAT when running at WOT versus at idle because of the higher cooler air volume and velocity moving through the intake manifold at WOT versus at idle.
Is this typical of the 496 PCM555 IAT system?
Is this typical of the 496 PCM555 IAT system?
#2
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Re: Merc 496 GURU Question
Rage,
I suppose it will depend on the installation, but after looking at some recorded files for 496's, there seems to always be a drop in MAT as the engine is throttled up to WOT or even cruise. Typical drop seems to be about 10 degrees and somtimes more.
Dave
I suppose it will depend on the installation, but after looking at some recorded files for 496's, there seems to always be a drop in MAT as the engine is throttled up to WOT or even cruise. Typical drop seems to be about 10 degrees and somtimes more.
Dave
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Re: Merc 496 GURU Question
Originally Posted by Dave_N
Rage,
I suppose it will depend on the installation, but after looking at some recorded files for 496's, there seems to always be a drop in MAT as the engine is throttled up to WOT or even cruise. Typical drop seems to be about 10 degrees and somtimes more.
Dave
I suppose it will depend on the installation, but after looking at some recorded files for 496's, there seems to always be a drop in MAT as the engine is throttled up to WOT or even cruise. Typical drop seems to be about 10 degrees and somtimes more.
Dave
Also the MAT readings always appear to change in stair steps as your data displays and those temperture step valves seem to always be the same valve in a temperature range. I believe the other MAT systems show a uniform temperature curve change and not this stairstep. I do not know what that means , just an obsevation. Any information on this?
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Re: Merc 496 GURU Question
Originally Posted by Dave_N
Rage,
I suppose it will depend on the installation, but after looking at some recorded files for 496's, there seems to always be a drop in MAT as the engine is throttled up to WOT or even cruise. Typical drop seems to be about 10 degrees and somtimes more.
Dave
I suppose it will depend on the installation, but after looking at some recorded files for 496's, there seems to always be a drop in MAT as the engine is throttled up to WOT or even cruise. Typical drop seems to be about 10 degrees and somtimes more.
Dave
Bill
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Re: Merc 496 GURU Question
Bill,
I have a bunch of other files, most are kind of similar because I typically record them on a test run consisting of idle/cruise/wot, and some of them record some kind of failure. If you have Diacom I could email you some files to look at.
Dave
I have a bunch of other files, most are kind of similar because I typically record them on a test run consisting of idle/cruise/wot, and some of them record some kind of failure. If you have Diacom I could email you some files to look at.
Dave
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Re: Merc 496 GURU Question
Originally Posted by Dave_N
Bill,
I have a bunch of other files, most are kind of similar because I typically record them on a test run consisting of idle/cruise/wot, and some of them record some kind of failure. If you have Diacom I could email you some files to look at.
Dave
I have a bunch of other files, most are kind of similar because I typically record them on a test run consisting of idle/cruise/wot, and some of them record some kind of failure. If you have Diacom I could email you some files to look at.
Dave
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