No offense taken John!!!! I messed up for sure. Lowering the idle rpm completely slipped my mind, to much mind clutter.

I will be ordering the techmate pro first thing tomorrow morning.

Just a thought and please don't flame me too much, if I raised the idle back to where it was could the alarm stop going off if it in fact was the cause of setting the alarm? I'm not going to run it till I get the scanner,was just wondering.

forgot your app stock and all the fuel system and throttle body - I remem you have a drag car that runs on E 85. But forgot about how is 496 set up ??

next why did you have to lower your idle in the first place ? Did it raise by itself for whatever reason or did you raise it at some point in time and now had to lower it ?

What is your idle rpm now and what was it before ? I would rather know true rpm thru the scan tool than a dash tach - what gauges - do you have smartcrat gauges ???

Good memory John! E85 street car and bone stock 2002 496.

Just before i purchased boat in September 2012 the iac was changed. Don't remember idle rpm when I bought it but it seemed to raise itself a little over time. When I bought it it was very smooth going into gear. With the higher idle it was not as smooth. I know bravo's don't like to much rpm with shifting. With the recent lowering of idle it was smooth again. I think it was idling at 800 on stock Liviourse tach. From my reading a 496 should idle about 650.

Idle is about 700 on stock tach now, no smart craft gauges.

Idle has to be tested at fully warmed up 100 % reading the correct water temps within specs. it should be at 650 rpms using the scan tool and you can verify the engine temps with the scan tool as well to compare that against the dash gauge.

800 rpm too high for a stock app.

Possible throttle cable and or its adjustment

Vac leak

do you have stock flame arrestor and a very clean one at that ?

IAC muffler ??? a clean one installed and cavity clean and unrstricted and the long hose going back to the IAC ???

Also IAC gasket seal LEAK - hopefully new gasket was installed on very clean surfaces for the IAC itself the last time it was changed.
Also brand of IAC and its PWM readings at idle and start up

engine serial number ???

and this week killed me, first day off this whole month and people still bringing me boats this mourning. Jeez

Yes engine completely warmed up. Again going by factory tach as that's all that i have.

I checked throttle cable adjustment. The tb shaft was against the stop screw. I bought the shift cable adjustment tool as well. (I don't take short cuts. Try to do everything by the book)

No vacuum leaks.

Stock arrester that is cleaned several times a year. New iac filters always as part of my routine maintance. Hose is straight with no obstructions.

I'm pretty sure it is a Mercury iac (matching black] as the gentleman I purchased boat from was also very anal and took it to a merc tech. New gasket as well. I can always remove iac and replace gasket (after I get scanner). No iac readings on scanner YET. Will have by end of this week on my new scanner.

Serial # 0M084752

Hour meter has 420 hours now, purchased with 275ish hours. First problem that has come up for me. I have only done maintenance up to date. Very pleased with engine and boat. Before I purchased boat, Velocity went over it as they were going to broker boat. When I called Velocity to purchased tabs and steering I was told it was a solid boat.

John just a side question, does the diacom software do a lot more than the techmate pro? From what I can gather it will log and export unlike the scanner. This will only be used by me for the most part. I'm leaning toward the scanner. I know you have both.

Also over the years I know you were selling off your service manuals. I currently have number 30. Is there a better one to have?

Thanks so much for taking time out of your busy schedule to offer your help. It is greatly appreciated!!!!

I was giving you a hard time about the shift cable tool last time about making it instead of buying it but you took me wrong, totally unstandable and all water under the bridge after the fact. I remember that but will add I was talking about the throttle cable in above posts just saying.

Diacom techmate pro IMO is better for testing while lake running - I velcro it to my arm so I can drive and watch it. Also no laptop needed as it is just one simple plug and play. BUT the DIACOM SOFTWARE has a better diagnostic layout and can show more along with more capabilities, I have both to do what is needed for however. IMO the person who is not going to perform scans day in day out or even once a week - the techmate pro is a very good to have.

the 496 has 4 different engine side manuals thru out starting in late 2000 - IMO I would own that one and the next 1 or 2 after that - the NON catalyst ones if I was going to work on your own 496 app, The earlier 496 's some of the material does not apply in the later manuals but if you had to changed some parts that are NLA parts to current part offered - those manuals sure will come in handy.

John I totally forgot about making the shift cable tool. Like I said you have a good memory. Lol At the time I just bought a milling machine and wanted to use it. But reality set in and I just bought one. Sometimes I need to be shown the light. I didn't mean anything about buying the correct tools. Just stating I bought quite a few tools that will probably only get used once. They are building fast

Yes I knew you meant the throttle cable. I went over everything. All is good.

Thanks for the info on the scanner and manuals. I'll be purchasing the techmate pro first thing in the morning. I'll also keep an eye out for the other manuals.

Thanks again for the help.

I've had 2 boats both had same problem. It was the tube that brings the water into the boat clogs up after time and has to be replaced. you have to take off the lower unit follow the intake hose and there will be a plastic fitting that clogs up. a real pain to change.

Thanks big lock. I purchased scanner this morning and should be here Thursday. I'm going to scan it before I do anything else.

I received the Techmate Pro scanner today.

Had 5 fault codes in history: 94 pitot pressure, 75 fuel level, 118 steering, 131 trim and 191 fuel level which all should be BS codes.

In the freeze frame had 5 also

1) 9 Engine Gaurdian at 4254 rpms available power 89%

2) 19 Maximum RPM Execeeded at 4247 rpms with 89% power available

3) 77 Camshaft sensor fault at 214 rpm at 406.9hrs

4) 132 Crank Position engine speed 214 rpm at 406.9hrs

5) 152 IAC Output
809 rpm, throttle 0%, block pressure 2.1psi, battery 13.8, available power 20%, fault freq count 6#

With engine warmed up idled at 700rpm, available power 89%, guardian mode not specified, TPS .60volts, IAC duty 99.9, sensor power 5.0volts, operation mode-idle, guardian state 2#

While raising the idle with throttle handle the IAC duty will stay 99.9% up to about 925rpm with available power at 100%. At about 950rpm the IAC duty goes to 0%, TPS voltage is .82volts with 100% available power. with no change in rpm with IAC duty changing.

It looks like my IAC is bad.

The scanner said TPS voltage at idle should be .90-1.22volts. So it looks like I need to adjust TPS Sensor to get correct voltage?