Ford Escort RS Turbo This forum is for discussion of all things pertaining to the Ford Escort Rs Turbo Series 1 and 2.

both sides of my coil are +ve, is this right?

Thread Tools
 
Search this Thread
 
Old 01-02-2007, 08:19 PM
  #1  
fezzie2
Wahay!! I've lost my Virginity!!
Thread Starter
 
fezzie2's Avatar
 
Join Date: Aug 2005
Location: lincs
Posts: 82
Likes: 0
Received 0 Likes on 0 Posts
Default both sides of my coil are +ve, is this right?

the ignition live goes to one side of the coil but when i test the other side of the coil (the one with the green wire from the ecu) it also gives out an ignition live, even when i crank the engine. is this right or is my coil fooked?
Old 01-02-2007, 09:29 PM
  #2  
1.9 xr2 on 40's
st170 breaking
 
1.9 xr2 on 40's's Avatar
 
Join Date: May 2004
Location: norfolk
Posts: 5,298
Likes: 0
Received 1 Like on 1 Post
Default

it earths via the plugs (hence the spark)
Old 01-02-2007, 10:02 PM
  #3  
fezzie2
Wahay!! I've lost my Virginity!!
Thread Starter
 
fezzie2's Avatar
 
Join Date: Aug 2005
Location: lincs
Posts: 82
Likes: 0
Received 0 Likes on 0 Posts
Default

ahh right, so the coil is ok?
Old 01-02-2007, 10:06 PM
  #4  
DazC
10K+ Poster!!
iTrader: (1)
 
DazC's Avatar
 
Join Date: May 2003
Location: Lancashire
Posts: 12,748
Likes: 0
Received 0 Likes on 0 Posts
Default

Yes.

The side of the coil marked up -VE should flash with a test lamp attached to it (wire still connected to the coil) when you crank the engine over. If it doesn't, it's not being triggered and is more than likely to be distributor or wiring related.

When it flashes off, the coil has been earthed (for a breif second) causing a collapse of the field within the coil creating the spark.
Old 02-02-2007, 12:37 AM
  #5  
SafeChav
10K+ Poster!!
 
SafeChav's Avatar
 
Join Date: May 2005
Location: Cheltenham, Gloucestershire
Posts: 13,798
Likes: 0
Received 0 Likes on 0 Posts
Default

fezzie2 sorry i never answered this for ya i have a habit of reading PM's and not responding for a while
Old 03-02-2007, 07:46 AM
  #6  
tabetha
20K+ Super Poster.
 
tabetha's Avatar
 
Join Date: Jul 2006
Location: uk
Posts: 24,596
Likes: 0
Received 3 Likes on 3 Posts
Default

As daz c says.
The coil is just that a coil of wrapped around another coil of wire wire.
It will of course be positve until it receives the opposing current on other end negative, this then generates a strong magnetically induced current in seconday(inner windings HT), when the negative is taken away by ignition circuit the filed induced voltage seeks a path to earth through the leads/plugs, all happens very quickly.
The ration of turns of primary and secondary coils dictates the voltage output as input voltage fixed 12v.
tabetha
Old 03-02-2007, 09:18 PM
  #7  
JesseT
PassionFord Post Troll
 
JesseT's Avatar
 
Join Date: Jun 2003
Location: Finland
Posts: 2,866
Likes: 0
Received 0 Likes on 0 Posts
Default

Other end is the constant +12V (black wire) and the other is the ignition live (green wire). At crank speed (~200rpm) a spark is given each 300ms. When you compare this with a common coil dwell time of ~5ms, you would see that at average the ignition live is only a few tenths of a volt short of the battery voltage.

tabetha, the coil ratio is not that important as it first seems. Remember that several tens of kilovolts are easily acchieved even with common coil ratios of less than 100.
Old 03-02-2007, 10:33 PM
  #8  
Rick
15K+ Super Poster!!

 
Rick's Avatar
 
Join Date: May 2003
Location: Stockport, Cheshire
Posts: 15,885
Received 17 Likes on 17 Posts
Default

if u have enough primary voltage!
Old 04-02-2007, 09:04 AM
  #9  
JesseT
PassionFord Post Troll
 
JesseT's Avatar
 
Join Date: Jun 2003
Location: Finland
Posts: 2,866
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Rick
if u have enough primary voltage!
Remembe that the primary is always operated by only 12V. How much voltage can be seen momentarily when the 12V circuit is broken depends on the primary coil inductance and it's resistance as the primary winding will exhibit a voltage of U=L*di/dt.
Old 04-02-2007, 09:31 AM
  #10  
DazC
10K+ Poster!!
iTrader: (1)
 
DazC's Avatar
 
Join Date: May 2003
Location: Lancashire
Posts: 12,748
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by JesseT
Other end is the constant +12V (black wire) and the other is the ignition live (green wire). At crank speed (~200rpm) a spark is given each 300ms. When you compare this with a common coil dwell time of ~5ms, you would see that at average the ignition live is only a few tenths of a volt short of the battery voltage.

tabetha, the coil ratio is not that important as it first seems. Remember that several tens of kilovolts are easily acchieved even with common coil ratios of less than 100.
The green wire isn't ignition live. The black wire is ignition live. The reason why you will find voltage on the green wire is because it's not been earthed yet.
Old 04-02-2007, 07:18 PM
  #11  
JesseT
PassionFord Post Troll
 
JesseT's Avatar
 
Join Date: Jun 2003
Location: Finland
Posts: 2,866
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by DazC
Originally Posted by JesseT
Other end is the constant +12V (black wire) and the other is the ignition live (green wire). At crank speed (~200rpm) a spark is given each 300ms. When you compare this with a common coil dwell time of ~5ms, you would see that at average the ignition live is only a few tenths of a volt short of the battery voltage.

tabetha, the coil ratio is not that important as it first seems. Remember that several tens of kilovolts are easily acchieved even with common coil ratios of less than 100.
The green wire isn't ignition live. The black wire is ignition live. The reason why you will find voltage on the green wire is because it's not been earthed yet.
Pardon my english, live was a badly chosen word. I meant the green one anyhow whatever you call it. My point was that at cranking speed it's earthed for such a small amount of time each time that a multimeter won't read anything.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
abz474
Cars for Sale
9
01-11-2015 06:53 PM
A.t.p
Ford Escort RS Turbo
14
23-10-2015 07:54 PM
nicodinho
Ford Non RS / XR / ST parts for sale.
6
07-10-2015 12:56 PM
gcfcos
General Car Related Discussion.
59
06-10-2015 05:04 PM



Quick Reply: both sides of my coil are +ve, is this right?



All times are GMT. The time now is 12:25 AM.