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496 Mag hesitation issues...

Old 09-04-2015, 11:45 PM
  #11  
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got your PM your serial number tells a lot - one you have the cam sensor that is available not the NLA you have the better crank sensor installed already and I know what fuel system you have along with which ignition coils you have. You have the Gen II coils in which are better. I know YOU DO NOT HAVE A DTS 496 because you have a IAC. With that said do you have smartcraft gauges and do you have a Bravo I or a bravo III being a Crownline as Crownline used a lot of the bravo III apps. thanks

My email is [email protected] best to email me there - thanks

put a title on the email also so I know who its from to open it.
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Old 09-08-2015, 04:12 PM
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I've seen many issues such as you describe with the 496's. The first thing you need to do is get it to a good mechanic that understands high performance and tuning on the 496's. Most shops don't have a clue. If it doesn't throw a code they are left with throwing parts at it. I'm retired now so I can't help you with the repair. "BUP" is a great resource on these forums and would be my first choice to recommend to look at your issues. I've had several customers that just were not happy with the crappy throttle response and hesitations on the 496- (mags) in particular. We resolved it by getting the PCM retuned by Whipple.

Bob Lloyd
ex-owner
Full Throttle Marine
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Old 09-08-2015, 07:38 PM
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Bob thank you for chiming in and the plug. I have the boat in my hands. Worked on it yesterday and finally got around today to scan the engine. I really have not had a day off in 2 months straight. The heat is killing me so today kind of did the complete scanning and freeze frame looks.

the boat is pristine condition and is a very nice boat but has many issues and some lack maintenance. Gen III cool fuel and the bottom 10 micron filter was very bad with even gasket material in it and large chunks of it. Very contaminated but was NOT internal paint that many see peeling from the GEN III cool fuel cell..

I feel bad for the new owner because the boat had these issues before he bought it and he was trying to learn all of this to fix it..

The biggest thing is all 3 batteries located on the starboard engine side is one of the worst cob job wiring and battery cables installed I have every seen coming from 85 K boat especially how pristine 99 % the condition is. At the starter the positive battery cables and leads were just about to fall off as the nut was not even close being tight.

12 volt battery cables and wiring were tied wrap to all the fuel lines with very sharp tie wrap cuts to bundle all that together. Huge dangerous situations could have happen from this install. Also can pull some of the battery and grounds cables straight out their connections by hand plus exposed wiring past the crimps. Very bad and poor crimps. Very poor install of the batteries, cables and wiring set up but the boat has the over powering stereo and amp set up for the listening pleasure installed. A couple of the ground cables are way too small diameter plus very cheap in quality.

History faults from the scan

Low voltage ( not hard to guess that one) but hopefully did not hurt the PCM over the long term of this.
Crank sensor - not worried about that one and same with cam fault
Shift in gear switch - will have to check on that one at the lake as well running to make sure it shows in GWR while running down the lake
Many Overspeed faults N

next the scanning parameters that stood out

IAC 64 % PWM at 2100 rpms that stands out 4 sure
MAP key on 10.54
BARO key on 14. 26 that stand out for the MAP
MAT key on cold engine 42 well hell no way on that one.

Anyways will be back on it tomorrow along with fuel pressure readings.

Lower unit severly impacted but was resanded and repainted with phantom black make over. Props have been damage at least twice rebuilt and still not right plus have many small dings and chips on them. Skeg length has at least 3/4 to one inch shorten to get rid of the damage that has taken place over time

Boat has 161 hours and had 78 hours of that 161 is idle speeds. I am sure this app was not broken in properly when brand new. Half its engine life was idle speed running around.

next again its a HO MAG and has never hit 4500 rpms - 4999 rpms in run history. never - either prop set up from day one was off or the owner was afraid of running WOT or a problem from day one not to be able to reach WOT.

Posting this as a word of warning because not the new owners fault but people who install stereo equipment or their own should learn on how to do it properly and not cause fire and or explosion problems with the install. This app could have been a bomb. The owner is extremely lucky that he still has a boat in one piece and I am not BS ing about that one. Who in the world tie wrap bundles 12 v battery and wiring cables to fuel lines. .

Last edited by BUP; 09-08-2015 at 07:45 PM.
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Old 09-08-2015, 10:11 PM
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I hear you on the heat! That's one of the main reasons I'm out of the business. It's really hard work. Sounds like you've got a handle on his problems.

Bob
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Old 09-16-2015, 08:30 PM
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Any more updates on this?
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Old 09-16-2015, 11:10 PM
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As was mentioned earlier in this thread, I took BUP(John) up on his offer to take an extensive look at the boat. I made the mistake of buying the boat over the winter without having it water tested or inspected. It was purchased from a guy on the Crownline forums that had a very good reputation. I can't say enough good things about John. I hauled the boat to him last Monday(Labor Day none the less) and he immediately began looking over the boat. What was great about John is that he wanted me to stay so that he could show me everything. We went over the boat for nearly 7 hours. John is meticulous and was very mythodical about evaluating the boat. He found a variety of issues. The boat is in wonderful shape but, the previous owner did neglect quite a bit of maintenance. John ended up keeping the boat another 5 days, including 2 water tests with me. In the end, there were quite a few issues found and here are what was done to remediate:
Bad IAC
IAC muffler pinched
Cool Fuel filters(upper & lower) replaced. **The lower was extremely dirty**
MAP sensor was misaligned
Water pressure sensor replaced
Numerous grounds were lose causing inconsistent voltage to sensors and PCM - All tightened now

I took the boat out today and it is night and day. When I took the boat to John, it had a horrible hesitation/stumble and the top speed was 45mph at 4050rpm. Clearly the boat had issues. As of this afternoon, the boat ran 54mph at 4800rpm. The hesitation is gone and it comes out of the hole much quicker and picked up 9mph and 750 rpm.

John is the only person that will touch my boat moving forward. Again, I can't say enough good things about John and would recommend him to anyone.

Todd
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Old 09-16-2015, 11:10 PM
  #17  
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As was mentioned earlier in this thread, I took BUP(John) up on his offer to take an extensive look at the boat. I made the mistake of buying the boat over the winter without having it water tested or inspected. It was purchased from a guy on the Crownline forums that had a very good reputation. I can't say enough good things about John. I hauled the boat to him last Monday(Labor Day none the less) and he immediately began looking over the boat. What was great about John is that he wanted me to stay so that he could show me everything. We went over the boat for nearly 7 hours. John is meticulous and was very mythodical about evaluating the boat. He found a variety of issues. The boat is in wonderful shape but, the previous owner did neglect quite a bit of maintenance. John ended up keeping the boat another 5 days, including 2 water tests with me. In the end, there were quite a few issues found and here are what was done to remediate:
Bad IAC
IAC muffler pinched
Cool Fuel filters(upper & lower) replaced. **The lower was extremely dirty**
MAP sensor was misaligned
Water pressure sensor replaced
Numerous grounds were lose causing inconsistent voltage to sensors and PCM - All tightened now

I took the boat out today and it is night and day. When I took the boat to John, it had a horrible hesitation/stumble and the top speed was 45mph at 4050rpm. Clearly the boat had issues. As of this afternoon, the boat ran 54mph at 4800rpm on bad props. The hesitation is gone and it comes out of the hole much quicker and picked up 9mph and 750 rpm.

John is the only person that will touch my boat moving forward. Again, I can't say enough good things about John and would recommend him to anyone. His attention to detail is second to none.

I'm working to get on John's schedule this winter to remove the (3) battery setup and awful cables in lieu of a dual battery setup(1 per side) with all HD marine cables.

Todd

Last edited by ToddEdge; 09-16-2015 at 11:17 PM.
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Old 09-17-2015, 09:49 PM
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Sounds like you had a lot going on. Glad it all got fixed up. I'm always interested in any problems and fixes for the 496's.
I have never met BUP but have read most if not every post he makes on the 496 and have no doubt he took care of you. After reading post #4 from him explaining why he didn't initially respond to this thread as to not step on any fellow local business toes really struck me. Talk about integrity!
Thanks for the update.
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