Intermittent Starting Issue

Intermittent Starting Issue

Author
Discussion

mattgtd

Original Poster:

322 posts

137 months

Tuesday 22nd April 2014
quotequote all
Had an issue come to light over the Easter break, a couple of times the car was turning over fine but failing to start up. Now the car has had the imobiliser ripped out previously so it's not that, the fuel pump was primimg all fine and the starter motor was turning it over at a really good rate.
It did this a couple of times over the 4 day break, but started fine the other 20 odd times fine.
When it happened I just found that waiting a minute then trying again it seemed to start fine?
The car has had new plugs around 800 miles ago, although from looking through the history I think the leads are a couple of years older and the coil looks older too.
From what I have read online through searches etc I think it could be the igniton amp maybe?
Any ideas?

Rugbyfester

180 posts

135 months

Tuesday 22nd April 2014
quotequote all
Hi Matt - Certainly sounds like the module, Coil Leads, Distributor/Rotor area, I am sure someone will be along soon with how to check exactly which bit, is broken down.

I understand that if you run it in the dark with the bonnet up you may see sparks around the module etc that will indicate a break down (I haven't tried myself).

mattgtd

Original Poster:

322 posts

137 months

Wednesday 23rd April 2014
quotequote all
Rugbyfester said:
Hi Matt - Certainly sounds like the module, Coil Leads, Distributor/Rotor area, I am sure someone will be along soon with how to check exactly which bit, is broken down.

I understand that if you run it in the dark with the bonnet up you may see sparks around the module etc that will indicate a break down (I haven't tried myself).
Hi Paul, yes I agree, with my limited knowledge I do think it must be either 1 of the parts you have listed above, or a combination of 2 or more of them maybe?
Anyone else got any ideas / experience of this?
Cheers.

ukdj

1,004 posts

184 months

Wednesday 23rd April 2014
quotequote all
You need to work through the system to see where it has failed, difficult to do when it is working ok though!

Check all the HT Leads including the king lead with a multimeter for resistance are they all about the same or are there one or other leads that standout different?

Inspect dizzy cap/rotor arm for corrosion/build up & signs of arcing, also check with bonnet up in the dark for any signs of arcing from the ignition components whilst cranking/running

Inspect plug extenders for signs of wear/poor connections/arcing

Inspect wiring to coil/ignition amp for broken/corroded connections - it may just be an internal break in one of these wires causing the intermittent fault!

To work through I'd do :-

1) Remove fuel pump relay to prevent flooding while cranking

2) connect known good HT lead to coil directly to a spare/removed spark plug, leave plug on top of the plenum and crank it over, do you get a good fat blue spark ?

if yes problem is not coil/ignition amp, look at the dizzy cap/rotor arm

if you get a weak yellow spark, then the problem is either coil/ignition amp

To check coil :-

With the ignition on check you have +12v at the coil, remove connections to the coil, check resistance of low tension circuit -ve to +ve using 2k range and then check the resistance of low to high tension circuit -ve to king lead connector using 20k range if coil checks out ok then problem is ignition amp

hope this helps

Regards

UKDJ

mattgtd

Original Poster:

322 posts

137 months

Wednesday 23rd April 2014
quotequote all
ukdj, thanks for the reply, that has given me a good idea of how to check it over this weekend, hopefully it will be something simple hey!

ukdj

1,004 posts

184 months

Wednesday 23rd April 2014
quotequote all
Unfortunately intermittent faults usually aren't easy to find unless you can reproduce the issue!

Because of the intermittent nature everything may check out ok, the fault may only show whilst under load etc

Best of luck, if you need further help just ask.

Regards

UKDJ