mis firing then cutting out

mis firing then cutting out

Author
Discussion

chris212

Original Poster:

133 posts

158 months

Sunday 14th June 2015
quotequote all
After around 20 minutes driving today and as soon as i put my foot down it mis fired, the rev counter needle bounced around and it cut out. I pulled the bonnet up and checked the dizzy cap( recently replaced rotor arm as it has developed a slight miss and i thought it may be that). After 5 mins it started up again ok. It dove ok if i took if easy, but repeated the initial symptoms if i gave it some. It seems ok while its warming up.
Its a 4.3 pre cat. Any help appreciated!


QBee

21,009 posts

145 months

Sunday 14th June 2015
quotequote all
So something is having a problem creating an organised explosion when the engine/engine bay is hot and under load.

Did you keep the old part? Tried putting it back on?
I tend to check the plug extenders when there's a slight misfire. Make sure they are really on tight. Especially the no 8 lead ( nearest the driver)

If tha doesn't sort it, this feels like coil or ignition amplifier to me.

Edited by QBee on Sunday 14th June 23:27

Toma500

1,221 posts

254 months

Monday 15th June 2015
quotequote all
Sounds like the ignition amp has gone to me had something similar a couple of years ago .

Barreti

6,680 posts

238 months

Tuesday 16th June 2015
quotequote all
The ignition amp is relatively cheap and simple to fit.
As Toma500 says, your symptoms point to this so I'd replace that as your starting point.
Be sure you get the one with the correct number of pins, yours should be a 2 pin.
And get some heatsink compound too - this stuff from Maplin linky

chris212

Original Poster:

133 posts

158 months

Tuesday 16th June 2015
quotequote all
Bought an amp today off ebay (powerspark). Its got the 3 pins but comes with the conversion wire . Hope this is right! Will let u know how i get on.

Hoover.

5,988 posts

243 months

Tuesday 16th June 2015
quotequote all
Chris, you can still get the two pin amps, they just need sourcing... Bespoke Performance in Ware got me one, I was the first person in a long time who wanted one, so they will remember it well.

chris212

Original Poster:

133 posts

158 months

Monday 22nd June 2015
quotequote all
Fitted new amp. Made a huge difference- even reduced shunting. I'm still getting a slight stutter when I really give it some! Don't know if it just needs a few miles to clear itself out? I want to check the coil next. Any tips on how to do that? Is it just a case of testing the primary and secondary on the coil. If so does anyone know what the readings should be? Thanks.

QBee

21,009 posts

145 months

Tuesday 23rd June 2015
quotequote all
chris212 said:
Fitted new amp. Made a huge difference- even reduced shunting. I'm still getting a slight stutter when I really give it some! Don't know if it just needs a few miles to clear itself out? I want to check the coil next. Any tips on how to do that? Is it just a case of testing the primary and secondary on the coil. If so does anyone know what the readings should be? Thanks.
Give it a good 50 mile blast at fairly high revs before you do anything else. There must be a fair amount of rubbish to clear

EGB

1,774 posts

158 months

Wednesday 24th June 2015
quotequote all
chris212 said:
Fitted new amp. Made a huge difference- even reduced shunting. I'm still getting a slight stutter when I really give it some! Don't know if it just needs a few miles to clear itself out? I want to check the coil next. Any tips on how to do that? Is it just a case of testing the primary and secondary on the coil. If so does anyone know what the readings should be? Thanks.
Steve Heath TVR Griff/Chim manual tells how to check coil, page 69. Primary resistance 1.2-1.4 0.5 horse shoe symbol.
Secondary resistance 7500-9500

Sardonicus

18,964 posts

222 months

Wednesday 24th June 2015
quotequote all
A duff coil will take down a healthy ign module so yeh check it out frown

Barreti

6,680 posts

238 months

Wednesday 24th June 2015
quotequote all
This is a bit numpty for Part 1 but Part 2 it is a very simple but useful explanation of what those numbers EGB just quoted are actually used for.
http://www.wikihow.com/Test-an-Ignition-Coil