new cam new programming?
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=43022
Printed Date: October-06-2024 at 2:29pm
Topic: new cam new programming?
Posted By: maxhighlife
Subject: new cam new programming?
Date Posted: June-23-2018 at 11:16pm
I have a higher lift cam on my stock rebuild and notice I have a lot of carbon buildup and bad idling sometimes is there programming changes needed for the fuel injection?
2004 ski nautique PCM 5.7 chevy 330hp
264/270 @.006
212/218 @.50
.488/.498
LSA 112
ICL 110
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Replies:
Posted By: KENO
Date Posted: June-24-2018 at 9:25am
The link below is to your post from almost 5 years ago with a question about this same cam
http://correctcraftfan.com/forum/forum_posts.asp?TID=30668&KW=&PID=398292&title=cam-up-grade-opions#398292" rel="nofollow - link
No answers back then
Have you been running this for a number of years with these symptoms or did they just start?
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Posted By: maxhighlife
Date Posted: June-24-2018 at 4:44pm
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yes no one provided any info, I finally decided to do the build this spring and used the comp cam hoping the pcm would detect the air flow change and make the adjustments but no luck. I bought the MerCruiser Scan Tool but I have not found it to be useful to make adjustments. I guess there are not many people experimenting with fuel injected boats? Thanks for the response
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Posted By: KENO
Date Posted: June-24-2018 at 4:54pm
Where's the carbon buildup and you also mention bad idling sometimes, must mean it idles good sometimes?
How about the easy stuff like a new distributor cap and rotor, coil wire and plug wires etc?
These engines (5.7 excalibur) seem to have an appetite for distributor caps.
It seems like it couldn't hurt to replace the stuff mentioned if it's been a while.
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Posted By: JoeinNY
Date Posted: June-24-2018 at 8:06pm
Keno is probably right on the money, but indeed there is no closed loop feedback from an o2 sensor or the like for your engine just hard coded tables controlling fuel and advance so yes if you really made a big enough change you might be continuously out of tune.
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http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001
1967 Mustang 302 "Decoy"
http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video
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Posted By: maxhighlife
Date Posted: June-24-2018 at 9:11pm
yes the idling issue seam to appear after a run back to the ramp when loading the boat or idling around the dock when just bumping back and forth between forward and reverse and reminds me of a carb loading up I can "blow it out" and its good for a short time but it does smell rich.
I have put new ngk plugs, cap and button, wires.
I have been thinking about the MAP sensor and pondering if the higher lift cam may be causing the disturbance in vacuum readings and if a different sensor from maybe a truck "possible a different orifice" would make a difference, or is the sensor truly just a reporting mechanism.
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Posted By: KENO
Date Posted: June-24-2018 at 9:35pm
Don't know about a different one making a difference, but the MAP sensor along with the TPS tells the computer what the load on the engine is.
So if the computer is seeing different vacuum numbers from the MAP sensor, it'll be adjusting things differently.
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Posted By: throttle out
Date Posted: June-25-2018 at 9:18am
I would venture a guess that with your bigger cam you are not pulling as much vacuum at idle. Given that you seem rich at idle I would think the fuel management system thinks your not quite idling given the lower vacuum the map sensor likely is seeing. When the motor is idling decently what rpm is it holding?
Also given no mention of it I assume the motor otherwise runs well?
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1989 Ski Nautique 2001 351 PCM w/ 1-1.23
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Posted By: maxhighlife
Date Posted: June-25-2018 at 8:45pm
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yes that is correct it runs fine otherwise, 800-1000 seems to run fine. I'll continue to experiment and report back if I find any good info Thanks
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