car won't start??

Need technical Q/A then you're in the right place

Moderator: martauto

Post Reply
User avatar
k10
E30 Zone Newbie
E30 Zone Newbie
Posts: 157
Joined: Sun Oct 02, 2005 11:00 pm

Thu Jan 31, 2008 9:35 pm

We have a track slapper and have just changed the clutch. Went to start her up after the clutch change but she's not having it.

Battery is okay. Startor motor is turning over. Fuel in the tank and fuel is being delivered as we took off one of the fuel hoses to verify this.

We do NOT appear to be getting a spark at the plugs anymore.

Any ideas why? Could we have damaged something when changing the clutch? We did have to do a fair bit of prodding in the engine bay to remove the top bolts that mate the engine to the gearbox.

Perhaps we have knocked / split a wire?

Or perhaps the coil has decided to pack in at an inconvenient time?

Any ideas greatfully recieved?
User avatar
Brianmoooore
E30 Zone Team Member
E30 Zone Team Member
Posts: 49358
Joined: Mon Jan 10, 2005 11:00 pm

Thu Jan 31, 2008 11:12 pm

Always helps to know what engine we're talking about!
User avatar
k10
E30 Zone Newbie
E30 Zone Newbie
Posts: 157
Joined: Sun Oct 02, 2005 11:00 pm

Fri Feb 01, 2008 12:16 pm

325 M20
User avatar
Brianmoooore
E30 Zone Team Member
E30 Zone Team Member
Posts: 49358
Joined: Mon Jan 10, 2005 11:00 pm

Fri Feb 01, 2008 8:09 pm

Do the plugs get wet with unburnt fuel after cranking it?
Is there power at the ignition coil + terminal when the ignition is on?
User avatar
k10
E30 Zone Newbie
E30 Zone Newbie
Posts: 157
Joined: Sun Oct 02, 2005 11:00 pm

Fri Feb 01, 2008 8:45 pm

Yes plugs are wet with unburnt fuel after attempting to start her.

Not sure if power at the coil as not tested yet. I'm going to remove the coil off my convertible and try that tomorrow.

Cheers

K
ricointheuk
E30 Zone Newbie
E30 Zone Newbie
Posts: 24
Joined: Thu Jan 25, 2007 11:00 pm
Contact:

Sat Feb 02, 2008 1:15 pm

no power to the coil. Chsanged coils and no 12 v reading from coil terminal. Power at ignition swirch and startor motor? No power at wires leading to coil?
Anyone know if their is a sensor in the clutch / gearbox housing which would tell the engine not to turn if the clutch had been incorrectly fitted?

Cheers

K
User avatar
Brianmoooore
E30 Zone Team Member
E30 Zone Team Member
Posts: 49358
Joined: Mon Jan 10, 2005 11:00 pm

Sat Feb 02, 2008 1:38 pm

Who is ricointheuk? OP was from k10! Is this a further comment on the same car, or a different one with similar problems.
I know my way around E30s, but my powers do not extend to remote mind reading!!!
ricointheuk
E30 Zone Newbie
E30 Zone Newbie
Posts: 24
Joined: Thu Jan 25, 2007 11:00 pm
Contact:

Sat Feb 02, 2008 3:50 pm

hi brian
this is K10, Rico is my mate, we own the track car 50/50, so part of original post.

We have tested coil and we think it is okay. We tried direct connection of coil to battery to produce a spark at the plug but it didnt like this !

We have changed the clutch and are now wondering if the clutch / fly wheel position sensor is telling the car not to start as perhaps we have clutch internals in the wrong place so for the safty of the gearbox the sensor attached to the front of the gearbox has decided not to allow any power to the plugs?

Anyone have any experience of this?
User avatar
Brianmoooore
E30 Zone Team Member
E30 Zone Team Member
Posts: 49358
Joined: Mon Jan 10, 2005 11:00 pm

Sat Feb 02, 2008 5:13 pm

If there is no power to the + terminal of the ignition coil, it is not an engine problem.
The + terminal of the ignition coil is fed directly from the ignition switch, via a green wire. The only connectors in this wire are: a multi pin plug and socket clipped to the steering column about half way down, a two pin immobiliser socket (with a shorting loop fitted, if no immobiliser) above the middle of the glovebox, and the c101 engine loom connector.
There are no safety systems such as you suggest.
Is this the ancient management system with sensors on the bell housing?
ricointheuk
E30 Zone Newbie
E30 Zone Newbie
Posts: 24
Joined: Thu Jan 25, 2007 11:00 pm
Contact:

Sat Feb 02, 2008 6:18 pm

fixed it :)

Swapped the position and speed sensor cable connectors around! Not sure whether we have fixed the problem or bypassed it but she now works.

Yes it is the old system with sensors on the bell housing.

Let us know if we have not really fixed it ;)

Thanks
User avatar
Brianmoooore
E30 Zone Team Member
E30 Zone Team Member
Posts: 49358
Joined: Mon Jan 10, 2005 11:00 pm

Sat Feb 02, 2008 7:14 pm

It won't go with the sensors the wrong way around, and if it goes now that you've swapped it, that must have been the problem.
Doesn't explain about the lack of power to the ignition coil though.
CPS on the front of the engine is only connected to the diagnostic connector on this engine.
If this is a track car, you'd be well advised to ditch this primitive system in favour of a later one, so that you can do a little mild tuning.
User avatar
Brianmoooore
E30 Zone Team Member
E30 Zone Team Member
Posts: 49358
Joined: Mon Jan 10, 2005 11:00 pm

Sat Feb 02, 2008 8:20 pm

Brianmoooore wrote:Doesn't explain about the lack of power to the ignition coil though.
Sorry, Wrong thread!!
ricointheuk
E30 Zone Newbie
E30 Zone Newbie
Posts: 24
Joined: Thu Jan 25, 2007 11:00 pm
Contact:

Sat Feb 02, 2008 10:11 pm

Brianmoooore wrote:
Brianmoooore wrote:Doesn't explain about the lack of power to the ignition coil though.
Sorry, Wrong thread!!
Although you said it was the wrong thread we did think we had that problem. On the coil there are + and - signs buy the terminals, so we put a tester across them and received no reading. Later we discovered that both wires that attach to the coil had + going along them, hence no reading on the tester.
ricointheuk
E30 Zone Newbie
E30 Zone Newbie
Posts: 24
Joined: Thu Jan 25, 2007 11:00 pm
Contact:

Sat Feb 02, 2008 10:13 pm

Brianmoooore wrote: CPS on the front of the engine is only connected to the diagnostic connector on this engine.
If this is a track car, you'd be well advised to ditch this primitive system in favour of a later one, so that you can do a little mild tuning.
Can you expand on this for me, please cps? thanks
User avatar
k10
E30 Zone Newbie
E30 Zone Newbie
Posts: 157
Joined: Sun Oct 02, 2005 11:00 pm

Sat Feb 02, 2008 10:14 pm

Thanks for your help Brian from K10 and Rico
User avatar
Brianmoooore
E30 Zone Team Member
E30 Zone Team Member
Posts: 49358
Joined: Mon Jan 10, 2005 11:00 pm

Sat Feb 02, 2008 10:16 pm

Coil - terminal is earthed by the ECU momentarily when a spark is required, so all you were reading on the- terminal is the voltage on the + terminal through the coil primary.
An example of why you should fault find with a 12 volt bulb, not a meter, as I have posted many times before!
User avatar
Brianmoooore
E30 Zone Team Member
E30 Zone Team Member
Posts: 49358
Joined: Mon Jan 10, 2005 11:00 pm

Sat Feb 02, 2008 10:19 pm

CPS = crank position sensor. Your cat has a TDC (top dead centre) position sensor as well.
Post Reply