Coil Testing

[Wilky 5]

Could someone tell me how to test an ignition coil? My car is an 89 1.9GTi with a Bosch coil if it makes a difference.

 

I've read in the Haynes about testing continuity etc but I've no idea what to set the multimeter or where to put the probes

[DamirGTI 342]

Good illustrated coil testing/inspection read :

 

http://www.aa1car.com/library/ignition_coils.htm

 

Is it something wrong with the car , or you just want to know how to test the coils ?

 

D

[Wilky 5]

Cheers mate, the car is massively overfueling - like a trail of fuel vapour from the exhaust (I've put a video up in a post)

 

I want to check that it's sparking enough and working as it should

[DamirGTI 342]

Well , excessively lean and rich mixtures are hard on the system to ignite them , thus the combustion process is very unstable in both cases .. and cod be dangerous for the engine if not rectified in time .

 

Need to sort out the fuel issues first , possibilities - ECU temp. sensor (tells the ECU how much fuel to add based on coolant temperature reading , known as NTC sensor i.e. negative temp sensor) , AFM (air flow meter , tells the ECU how much air and at which temperature enters the induction system , transferring this data into voltage reading/output and also serves as a "brain" for the ECU for fueling) , fuel system/injection poorly adjusted ..

 

D

[2052NV 24]

Make sure you check for carbon/arcing between the dissy cap carbon tip and the rotor, this is a sign of a weak spark and before you change anything, swap your ignition module with a 100% known good unit or a new bosch one, do not get a cheap chinese one..... trust me i just spent 2 months (on and off) trying to diagnose a hesitation my MI16 had (brand new everything installed) Turned out to be the brand new cheapo ignition module i installed two months ago (time the fault started occuring) causing the problem. Install a bosch one and fixed

[Wilky 5]

Make sure you check for carbon/arcing between the dissy cap carbon tip and the rotor, this is a sign of a weak spark and before you change anything, swap your ignition module with a 100% known good unit or a new bosch one, do not get a cheap chinese one..... trust me i just spent 2 months (on and off) trying to diagnose a hesitation my MI16 had (brand new everything installed) Turned out to be the brand new cheapo ignition module i installed two months ago (time the fault started occuring) causing the problem. Install a bosch one and fixed

 

I've renewed the rotor arm and distributor cap. The fault started as a slight misfire and it had been running sweet. I've new HT leads, used Bosch IA to replace the Ducellier one in case it's that, plugs, coolant sensor changed and I want to test the coil as I've been told by a Peugeot mechanic they're prone to them along with the king lead - he also said about the carbon tip as well. My car doesn't hesitate exactly, see the link!!

 

http://forum.205gtidrivers.com/index.php?showtopic=150087&hl=

[Wilky 5]

I've tested the coil. The Haynes spec says the following figures:

 

Primary windings, 0.8ohms

Secondary windings 6.5k ohms

 

My Bosch coil gives readings of 1.3 ohms and 7.77k ohms, is this faulty??

[welshpug 1,657]

I would say given it runs and you have an overfuelling issue that you'd need to check the fuelling side, given that the CTS is new then its likely the AFM is dead.

 

 

looking at the video, that looks more like a dead headgaket or rings to me, both of which would hamper the combustion process and make it appear rich.

Edited July 16, 2013 by welshpug

[Wilky 5]

I would say given it runs and you have an overfuelling issue that you'd need to check the fuelling side, given that the CTS is new then its likely the AFM is dead.

 

I don't think it's the head gasket as its not using water.

 

What's a CTS?

 

 

looking at the video, that looks more like a dead headgaket or rings to me, both of which would hamper the combustion process and make it appear rich.

[TooMany2cvs 65]

I don't think it's the head gasket as its not using water.

Not all head gasket failures involve the water jacket. Do a compression test.

What's a CTS?

Coolant Temperature Sensor. If that's stuffed, then effectively the choke's pulled out all the time.

[DamirGTI 342]

That's really , a lot of smoke .. gray ish smoke

 

Does it smell on un-burnt fuel , antifreeze or oil ?

 

Anyhow , ditto id certainly recommend compression test , and a leak down test as well .. to see the engine health state .

 

D

[Wilky 5]

The smoke smells of fuel. I did a compression test and one cylinder was down a bit on the others although I have also been told that overfueling could wash the bore and cause less compression

 

I changed the coolant sensor, plugs, leads, dizzy cap, rotor arm, used ignition amp, cleaned up the coil connections and then tried three different AFMs and another ECU!!

 

The car won't start with the AFM plug on and after a while of turning it starts and ticks over nicely albeit with all the smoke from the exhaust. If I reconnect the AFM plug the engine speed lifts slightly and runs smoothly for a few seconds and them cuts out!! I'm confused!!

 

If the head gasket was gone, how could it cause what it's doing??

[welshpug 1,657]

Sounds like you have duff afm or wiring, or wrong plug on the cts, make sure its the blue one.

[Wilky 5]

Sounds like you have duff afm or wiring, or wrong plug on the cts, make sure its the blue one.

It's the blue one. Anyway of checking the wiring? I've tried 3 AFMs so I doubt they're all faulty as two were off running cars

[Wilky 5]

I've tested the coil. The Haynes spec says the following figures:

 

Primary windings, 0.8ohms

Secondary windings 6.5k ohms

 

My Bosch coil gives readings of 1.3 ohms and 7.77k ohms, is this faulty??

Are these values reasonable?

[AndyCrom 64]

whats the condition of the brown multiplug under the AFM, this is the multiplug that feeds amongst other things the 2 pin CTS

[Wilky 5]

whats the condition of the brown multiplug under the AFM, this is the multiplug that feeds amongst other things the 2 pin CTS

Not checked it, what's it's function?

[AndyCrom 64]

the multiplug is known for getting covered in muck etc and also deteriorating to a point where the pins inside the connector are either loose or corroded, the multiplug feeds a number of sensors on the engine

[Wilky 5]

the multiplug is known for getting covered in muck etc and also deteriorating to a point where the pins inside the connector are either loose or corroded, the multiplug feeds a number of sensors on the engine

Definitely worth having a look at it then. If it appears to be a bit iffy, what's the best way of repairing it?

[AndyCrom 64]

Theres several schools of thought to fixing the loom of doom, all from cleaning up the original to cutting out the connector and directly solder the wires together and heat wrap (I personally hate the thought of soldered wires in any car) or just to replace the connector completely

 

 

have a look below at what I did on mine

http://forum.205gtidrivers.com/index.php?showtopic=141314&p=1335958

 

granted tho that the multiplug is the cause of the issue, but its a good place to look either way

[jackherer 543]

The CTS isn't routed through the brown multiplug.

 

Checking the wiring for it is the right move though, unplug the ECU and check the continuity to the CTS plug. Sometimes its as simple as the pins in the blue plug getting pushed back in the housing.

[Wilky 5]

I removed the AFM to check the brown plug, this is what I found:

 

 

I'm getting some switch cleaner and refit and see if it makes any difference, there is oil on the connections

[Wilky 5]

What are these, cable retainers or earthing points?

[Anthony 1,003]

The poster on the previous page was incorrect - the brown multiplug pictured is just for dashboard gauge and warning lights, the reverse lights, and the starter solenoid. It in no way influences engine running or has any engine management related sensors running through it.

 

You could unplug it completely and - with a push start - the engine would run fine (although the atlernator wouldn't charge until you dialled in enough revs for it to self-excite)

 

Those things pictured are cable retainers/clips

[jackherer 543]

The CTS isn't routed through the brown multiplug.

 

Does anybody read my posts?