Then there must be a reason my 03 never primes the system when the fuel pressure regulator failed on it. I'd put the key in the on position for a few seconds in hopes it'd run the fuel pump so it wouldn't dry start until I fixed it, i wouldn't hear anything outside with the door open. Even with that it would still take the same 4-5 seconds while cranking to start as if I didn't. On my 2021 i can hear the fuel pump priming before starting. But can't on those old ones. Don't know if something isn't working right.
Pausing After Key On Before Cranking
- Thread starter George7941
- Start date
You looking at how your infotainment behaves and applying it to all “electronic crap” is the issue and I guess that’s how all of these worries start.
People probably looking at how long their laptop or some other electronic device starts up and thinking the ECU in their car is the same. Lumping it all into one basket.
There are probably ~50 give or take a few ,different computer systems in a modern vehicle.
It's not a "worry" if it's a genuine problem. And none of it really matters, because by delaying the process and giving it more time, it solves the problem. It thereby becomes a viable solution. Regardless of what type of system it is, or how fast or slow it operates.
gathermewool
Site Donor 2023
Exactly.
A quick Google search shows modern ECU processors can operate up into the megahertz range. Mega = million, so that’s millions of cycles per second. I don’t know how much ECUs can process in each cycle, but it gives you an idea that a lot can be processed.
Another Google search shows that the CANBUS is capable of very high bitrates.
There also is no spinning hard drive to spin up.
I would also assume that everything needed to get the car started is in non-volatile memory (basically lookup tables for fueling, timing, etc), so that leads me to believe that the actual starting of the vehicle might not take much actual processing.
I‘m far from a computer wiz, but all of that tells me that startup times are not likely the limiting factor here.
Note, I’ve data-logged maybe 10-15 parameters at once before and I believe the sample rate for that is 10 samples per second. I believe that is done using spare processor processing time each cycle, so pretty fast.
//
I turn the key to ON for a second before starting, because the fuel pump priming noise is obvious and I’ve been conditioned to wait for that cycle to end. It’s only a second, so the dash hasn’t even come to life and my radar detector hasn’t gone through it self-check yet. I have gotten in and started it right away and there is not difference that I can tell.
My wife’s vehicle has pb start, so no idea what it does with the fuel pump.
If you call everything with a microprocessor a “computer” then sure, cars have many “computers” technically.
What most of you don’t understand is that most of these “computers” handle simple logic tasks to control various signals and don’t do any actual computing. They don’t run any software, just basic firmware that handles input/output signals. Almost like relays.
Even your microwave, fridge, washing machine have that, but did you ever hear about letting the “computer” in your washer start up? Do you give your microwave extra time to start up its “computer”?
All this talk is silliness.
My guess - having not looked into your vehicle specifically - is the screen not booting is a function of the BCU - not the ECU. Why it does that is beyond me - possibly the BCU takes longer to boot or has to get a signal from the ECU over CAN or something else that is firing too soon? If I had to make a guess - I assume this happened later in its life? Maybe the relay that powers it is sticking for a very short period of time and it doesn't get power immediately? Is there a separate relay for it somewhere?
On turning the key several processors typically need to "wake" - ECU, BCU, TCU, usually a separate control module for the air bags, ABS, etc. and there all usually connected via a bus.
You have no idea what you are talking about! Firmware is software and logic is computing. Yes your fridge and toaster boot up. They just do it really fast.
This is also computing.
So you recognize that a chip in a microwave can boot up really fast, but somehow that cannot be the case in a vehicle? And firmware is not software. Without firmware the chip is a useless piece of silicone. It would be like saying that breathing is same as thinking.
My point was that calling everything in a car a “computer” only serves to make them look complicated and mystical. Hence we have a thread about letting the computers “wake up”, with nothing but superstitions behind such claims.
Last edited:
I never said a car computer couldn't boot up fast, in fact I said the opposite. I don't think there is any reason to wait when turning the key.
The fact is that there are a lot of computers in a car and they are a lot more complex than you think. A microcontroller is a small computer system on a chip, so I stand by what I said.
I'd like to hear your explanation on how firmware is not software? How is firmware created and what is the difference?
gathermewool
Site Donor 2023
Not silly. This is a web forum and we’re discussing the topic. Seems pretty interesting and, most importantly, civil.
Years ago I had a car (1995 Ford Contour) with a battery that was too weak to crank the engine. So I push-started it.
Then I decided to take it for a drive on the interstate to charge the battery, since I didn't have a battery charger back then.
Well, it started to rain, so I turned on the headlights. The moment I did so, the engine misfired, or lost power for a split second.
My guess as to what happened is that the battery was so weak that it couldn't keep the voltage from sagging during that time between when I turned on the headlights and when the voltage regulator in the alternator could respond. (They don't respond instantly--the battery needs to be there to act as a buffer).
Because the voltage sagged, the ECU crashed. And rebooted. And it booted VERY quickly because the engine lost power for only a split second.
My next stop was to Montgomery Wards for a new battery. That should give you some idea how long ago this happened.
Then I decided to take it for a drive on the interstate to charge the battery, since I didn't have a battery charger back then.
Well, it started to rain, so I turned on the headlights. The moment I did so, the engine misfired, or lost power for a split second.
My guess as to what happened is that the battery was so weak that it couldn't keep the voltage from sagging during that time between when I turned on the headlights and when the voltage regulator in the alternator could respond. (They don't respond instantly--the battery needs to be there to act as a buffer).
Because the voltage sagged, the ECU crashed. And rebooted. And it booted VERY quickly because the engine lost power for only a split second.
My next stop was to Montgomery Wards for a new battery. That should give you some idea how long ago this happened.
My high level understanding is that firmware is embedded directly onto the chip and it enables its function. Otherwise it’s useless. Software is an external set of instructions stored externally from the chip itself. The chip has to communicate with another devise to retrieve that code and run it.
On the topic of fuel pump priming - some cars prime the pump when you unlock them, preparing for a start. This is why if you misfuel you shouldn't even lock the car, let alone try and start it (especially if you have put gasoline into a diesel tank).
On a previous BMW of mine I would hear it prime as I unlocked it and then every few minutes after that if I didn't start it immediately (for example if the car was unlocked and I was cleaning it or doing some job on it or whatever.
On a previous BMW of mine I would hear it prime as I unlocked it and then every few minutes after that if I didn't start it immediately (for example if the car was unlocked and I was cleaning it or doing some job on it or whatever.
Originally, the term firmware probably applied to software stored in a read only memory, but now applies to software stored in any kind of chip, including those that can be reprogrammed to allow a firmware update.
Firmware is generally used to refer to software that is designed for a specific function on an embedded system, not a general-purpose OS. DD-WRT would be firmware; Windows 10 would not be.
if that was necessary don't you think the engineers would of programmed that in?
I’m not a programmer so I don’t know the exact details and how the terminology started. They’re both a set of programming code, but the different naming was given for a reason.
That would be like saying aluminum wheels are steel wheels. Technically true, because both are alloys. But how would that be useful in a discussion?
I guess the best way to think about firmware is software that is stored in a chip and rarely changed..it may not even be possible to change it. Firmware IS software; a specific category of software.
I think both are categories or “ware”
I think both are categories or “ware”
If you've been around long enough you know what "warez" are.
