Engine Overspeed?

[dingbat]

I am of the belief that you can't own a modern car without a specific scanner. I have 6 different brands now.

Why would you need 6 different brands of scanner?

I own four “modern” cars. Somehow manage to identify what little has needed to done with a $20 special off Amazon.

 

[Leardriver]

Some of my cars have brand-specific service functions built into the scanner, such as rear brake release mode for brake service for BMW's.
My Mercedes scanner told me that the passenger floorboard temp sensor was causing the HVAC system to display an error. Silly things, but I live 50 miles away from the dealer for those two vehicles, and their hourly labor rate is something like $240.

 

[Leardriver]

My shop is about as well equipped as the dealership, at least for the stuff that matters, and I do what I can myself.

 

[QBhoy]

This is a simple one. The engine hasn’t hit anything over its normal rpm limiter figure. The print out shows as much. States 5149 rpm. That’s exactly where these hit the limiter. Mine hits it at that precise number very often.
The latter details there stating the time spent in each rpm band isn’t actually saying that it ran at the figure of 5400 or what ever it is…it’s just that the maximum rpm achieved of 5149 rpm falls into that band range. All perfectly normal.

 

[QBhoy]

Your MPI engine is run by the ECU. The ECU has fuel mapping that stops at about 5400 RPM. The spark mapping stops there as well. So the motor will never be able to reach a higher RPM on its own as it stops fueling and spark.

Well explained there Scott. Can I just add that these definitely limit at 5150 rpm. Almost exactly. I can verify that for sure.

 

[Scott06]

Some of my cars have brand-specific service functions built into the scanner, such as rear brake release mode for brake service for BMW's.
My Mercedes scanner told me that the passenger floorboard temp sensor was causing the HVAC system to display an error. Silly things, but I live 50 miles away from the dealer for those two vehicles, and their hourly labor rate is something like $240.

Yeah MB and BMW do some stupid chit these days. Wife loves her Mini ( aka BMW) but my god what a maintenance hog vs our Toyotas. Have one window on the mini that gets fooled into thinking it’s closed by the controller, also the rear view mirror doesn’t stay up. Easy change out right…. No the anti theft system has a component in the mirror, so yes I can see how you may need another scanner that can program.

i Used to drive German cars then I bought my first camry and no more. Worst fail I had (on my highlander) was an abs module , which is a $1700 part, this was after the car had 230 k of easy on the wallet Miles.

 

[QBhoy]

Yeah MB and BMW do some stupid chit these days. Wife loves her Mini ( aka BMW) but my god what a maintenance hog vs our Toyotas. Have one window on the mini that gets fooled into thinking it’s closed by the controller, also the rear view mirror doesn’t stay up. Easy change out right…. No the anti theft system has a component in the mirror, so yes I can see how you may need another scanner that can program.

i Used to drive German cars then I bought my first camry and no more. Worst fail I had (on my highlander) was an abs module , which is a $1700 part, this was after the car had 230 k of easy on the wallet Miles.

Bmw is a swear word for me today. Trying to get my 5GT back on the road after a few years. First issue was realising I needed a dealer or software assistance…just because I put a new battery in the bloody thing !! Didn’t end there either !

 

[JCJC]

Well explained there Scott. Can I just add that these definitely limit at 5150 rpm. Almost exactly. I can verify that for sure.

I thought it would be more obvious when it hit the limiter. I didn't hear or feel a thing. From now on I'll back off the throttle at 5k.

 

[stresspoint]

back on track to the Op , the 5.0 will never make enough power to hurt itself with OEM mapping.

with that said , i have seen a 5.0 mapped to run a tad over 6 k rpm ,
it was still a slug IE: make no power above about 5800.
once the exhausts were changed to extractor type (biggest let down on a Mercruiser), then it lit up and actually started to sound like a motor , when it was allowed it went well over the 6000 k rpm till the limiter was set by the map to keep the owner from going into the unknown..
so Op dont be stressing you motor is safe .

 

[JCJC]

back on track to the Op , the 5.0 will never make enough power to hurt itself with OEM mapping.

with that said , i have seen a 5.0 mapped to run a tad over 6 k rpm ,
it was still a slug IE: make no power above about 5800.
once the exhausts were changed to extractor type (biggest let down on a Mercruiser), then it lit up and actually started to sound like a motor , when it was allowed it went well over the 6000 k rpm till the limiter was set by the map to keep the owner from going into the unknown..
so Op dont be stressing you motor is safe .

I could see where an occasional 6k shift point might be OK for a stock engine in a street situation, but running it at a constant speed of 6k as you might in a marine application is asking for trouble. Was that guy's engine blueprinted and modded to safely rev that high? Mine is totally stock so I think it's wise to keep it under ~5k.

 

[Scott Danforth]

Mine is totally stock so I think it's wise to keep it under ~5k.

You could run your motor banging against the fuel map and rev limiter all day long and not hurt it.

 

[stresspoint]

as posted the in stock form 5.0 will run all day on the limiter.

with some tuning to the map and a decent exhaust 6k rpm will also not hurt a stock motor .

no need for blueprinting or balancing as the vortec 5.0 has solid bones from the factory..

point being your motor is solid enough to go alot harder than the factory map will allow it,

 

[QBhoy]

back on track to the Op , the 5.0 will never make enough power to hurt itself with OEM mapping.

with that said , i have seen a 5.0 mapped to run a tad over 6 k rpm ,
it was still a slug IE: make no power above about 5800.
once the exhausts were changed to extractor type (biggest let down on a Mercruiser), then it lit up and actually started to sound like a motor , when it was allowed it went well over the 6000 k rpm till the limiter was set by the map to keep the owner from going into the unknown..
so Op dont be stressing you motor is safe .

What were the details of the mapping, if you might know. Would love to know who can do that. How did they map that ecu to have the fuelling suited to those rpm ? I thought it was only pro charger or whipple or someone like that, who could manage an adjustment to the fuelling on these.
Perhaps it was a stand alone system ? Love to hear more, if you don’t mind. Thanks.

 

[stresspoint]

What were the details of the mapping, if you might know. Would love to know who can do that. How did they map that ecu to have the fuelling suited to those rpm ? I thought it was only pro charger or whipple or someone like that, who could manage an adjustment to the fuelling on these.
Perhaps it was a stand alone system ? Love to hear more, if you don’t mind. Thanks.

some things are better left off the internet ,so i am told !.

the guys that i play with that do this stuff messing with tunes are professionals that make a living from changing perimeters on ECUs , changing out chips., etc.
i have watched the tunes being done many times and it still scares the hell out of me when i see stock motors screaming and a guy with a lap top making changes, """too much hocus pokus for my brain to handle""".

its only scary for me as i am a carb and a tunable dizzy guy myself , my 500 hp 5.7 in my ski boat works for me , no computer anywhere to make that sing.