Definition of no start, no crank issues
Thread Starter
|
Moderator
Joined: Nov 2007
Posts: 2,185
From: Zurich
Definition of no start, no crank issues
Lately I have been reading a lot of threads where IMHO an explanation of a couple of things may help for a quicker troubleshooting.
This concerns non-start and non-crank issues
I would like to have a sticky post somewhere in the general tech help to point users to,to be able to give us a good description of their problem.
DEFINITIONS
================================================== ==============================
KEY-POSITIONS
--------------------------------------------------------------------------------
We do assume that an ignition key system has the following positions:
OFF =
key can be removed and will normally be inserted in this position.
This is the position where all electrical power which can be switched by the key is removed.
(There are exceptions as there are cars which you have to turn the key back for removal or push a button.)
SERV or AUX =
An intermediate position on some vehicles where you can use the radio, lift the windows but have no power to the engine controls and no check lights and no readings on gauges on the dash. (This is vehicle dependent.)
ON or RUN =
The position where you will definitively have check lights and gauges (ABS, SES, etc. some of which will switch off after self-tests are done) and this is also the position the key will return to after a successful engine start or simply when releasing the key. (Spring loaded)
In this position you will have power to all services, including ignition, fuel pump etc.
START or CRANK =
The position where you activate the starter motor via the starter relais. This is the position that can cause the clicking (relais), light clunk (starter magnet).
================================================== ==============================
NO-CRANK
--------------------------------------------------------------------------------
Is a situation where you have electrical current, the vehicle responds normally to turning the ignition key to "ON or RUN".
(showing check lights, gauges indicating proper values, etc.)
When turning the key to "START" it will NOT turn the engine over, with some or several of the symptoms below:
NO-START
--------------------------------------------------------------------------------
This assumes that turning the key to "START or CRANK" actually activates the starter motor and the engine is actually being turned over but refuses to start. Again there are several problems here that need a proper description. To name a few:
It simply turns but apart from being "cranked" or turned over by the starter absolutely nothing happens.
It is being turned over, starts as it would normally start then dies right away, as soon as the key is released to the "ON or RUN" position.
Any other of these symptoms, starting, idling for a while then stalling, etc.
A WORD OF CAUTION
--------------------------------------------------------------------------------
Starter motors are quite powerful electrical DC motors which pull an astonishing amperage to produce something around 2 - 3 hp (2kW) of electrical power and do this with only 12 Volts. They heat up quite a bit, especially when being stuck (no crank).
If a starter motor is not able to crank (turn over) the engine, release the key after a maximum of a couple of seconds.
If it is able to crank the engine do not use it for more than 15 - 20 seconds at a time (max.) and let it cool for at least a couple of minutes in between. After combined efforts of around 1 - 2 minutes (max.) let it cool for at least 30 minutes.
Please feel free to add your knowledge or tell me, i'll put it into the post.
This concerns non-start and non-crank issues
I would like to have a sticky post somewhere in the general tech help to point users to,to be able to give us a good description of their problem.
DEFINITIONS
================================================== ==============================
KEY-POSITIONS
--------------------------------------------------------------------------------
We do assume that an ignition key system has the following positions:
OFF =
key can be removed and will normally be inserted in this position.
This is the position where all electrical power which can be switched by the key is removed.
(There are exceptions as there are cars which you have to turn the key back for removal or push a button.)
SERV or AUX =
An intermediate position on some vehicles where you can use the radio, lift the windows but have no power to the engine controls and no check lights and no readings on gauges on the dash. (This is vehicle dependent.)
ON or RUN =
The position where you will definitively have check lights and gauges (ABS, SES, etc. some of which will switch off after self-tests are done) and this is also the position the key will return to after a successful engine start or simply when releasing the key. (Spring loaded)
In this position you will have power to all services, including ignition, fuel pump etc.
START or CRANK =
The position where you activate the starter motor via the starter relais. This is the position that can cause the clicking (relais), light clunk (starter magnet).
================================================== ==============================
NO-CRANK
--------------------------------------------------------------------------------
Is a situation where you have electrical current, the vehicle responds normally to turning the ignition key to "ON or RUN".
(showing check lights, gauges indicating proper values, etc.)
When turning the key to "START" it will NOT turn the engine over, with some or several of the symptoms below:
- Interior, exterior lights go dim
- Gauges and check lights go dim
- Clicking sound from somewhere up front but nothing else
- Mechanical "clunk" such as when the starter engages the flywheel but cannot turn the engine over.
- Nothing at all happens and everything (lights, gauges) stays as they were with the key in "ON" position.
NO-START
--------------------------------------------------------------------------------
This assumes that turning the key to "START or CRANK" actually activates the starter motor and the engine is actually being turned over but refuses to start. Again there are several problems here that need a proper description. To name a few:
It simply turns but apart from being "cranked" or turned over by the starter absolutely nothing happens.
It is being turned over, starts as it would normally start then dies right away, as soon as the key is released to the "ON or RUN" position.
Any other of these symptoms, starting, idling for a while then stalling, etc.
A WORD OF CAUTION
--------------------------------------------------------------------------------
Starter motors are quite powerful electrical DC motors which pull an astonishing amperage to produce something around 2 - 3 hp (2kW) of electrical power and do this with only 12 Volts. They heat up quite a bit, especially when being stuck (no crank).
If a starter motor is not able to crank (turn over) the engine, release the key after a maximum of a couple of seconds.
If it is able to crank the engine do not use it for more than 15 - 20 seconds at a time (max.) and let it cool for at least a couple of minutes in between. After combined efforts of around 1 - 2 minutes (max.) let it cool for at least 30 minutes.
Please feel free to add your knowledge or tell me, i'll put it into the post.
Thread
Thread Starter
Forum
Replies
Last Post
Unlimitedsp
Headers, Intake, & Exhaust
20
Jun 29, 2010 08:12 PM