hello boys & girls, i have a random running fault with my saff cossie.

its been running spot on for ages & last sunday i gave it large it 1st & quickshifted it into 2nd & BANG!!!!!!!!!!!!!

car rolled to a stop & the result was a broken diff but....................

when the car rolled to a stop i noticed it was running rough asif it was on 3 cylinders

car was towed to lock up & new diff fitted today, started car uo for 1st time since & its running rough still.

i tried another set of plugs in it & no joy


heres what it does:

runs rough on idle but assoon as throttle touched its mint & to drive it you wouldnt know there was a fault till its back on idel again.

when car runing rough on idle if u gove it 2-3 large revs it will the idel fine
or
if driving it & give it large then pull up it will idel fine

i did notice the engine does have a noisey tappet now & was thinking it could be that collapsed on idel (not enough oil pressure for it) causeing the valve not to be fully open when when revved & oil prerssure rises its all good

any other idears??????????????????

whn u pull a ht lead off 1 at a time the all make a differnce & its getting fuel & spark to all 4 cylinders

cheers

 

I would check the CO, if too weak it will always "attack" the weakest cylinder first, might just need richening up a bit.
Other fave areas are did the revs go sky high enough to bend a valve ?
tabetha

 

when you gave it beans in first, did you bounce it off the limiter? if you did you may have over revved it and hit a piston on one of the valves - its possible!

 

nah never valve bounced it

my 1st option was valve but if it was a valve it would allways idle rough

2day- get in car idleing rough, drive 2 mines perfect but everytime i stop idle rough, stop turnn it off.

start up 2 min later idel perfect & runs perfect

off-on, runs perfect

off-on runs perfect doe this 3/4 times

drove to dinner runing perfect, on way back stop at traffic lights & its running rough again

5/6 hrs later i go home & alls perfect again

valve cant be intermitant fault



my thoughts now are are:

may its a dodgy plug????
or
maybe lifter not opening vave on idle????? & when revved oil pressure rises & its ok???
& every now & then its ok??????

more inspection tomorrow

want 2 get it sorted so can take it classic ford sunday & run it up strip

 

It could be a lazy tappet, but you'd normally hear it, as one being distinctly noisy compared with the rest, they can be taken apart and cleaned out easy though, I did on mine(just rebuilt engine after 200K), mine even when left 2 weeks is 100% silent on start up, not even the faintest hint of rattle, the tappets have done around 100K.
tabetha

 

after your recent test, when you say running rough, do you mean 3 cyclinders?

if so, it could be a wiring fault to injectors, notorious common problem, especially on old looms

 

How do you take them apart?

 

tried dizzy cap, rota arm, leads & plugs & still no joy

tried another fpr as had this problem before & was that but still no joy

looks like the heads cimeing off when i get back from offshore for further inspection!

does seem like a valve problem when its running rough but dont get how it can be when the next minute its running mint??

runs on 4 cylinders but badly on idel (sounds like its on 3)