View Full Version : Surprise surprise, 1.2 8v problems!
Please help as I have had to leave the car at home this morning!
I have recently put a 1.2 8v carb 12nv engine into my Nova. It has been tuned to pass emissions and has had new oil/filter and plugs. It passed MOT last thursday.
Ever since I put it in, it was always a little hesitant, chuggy at low revs/high gears (more so than labouring). It usually goes fine if you give it death up through the gears.
When I try to start it on the choke from cold, it doesn't rev up like it should, it goes off a cylinder and makes the famous "baw baw baw baw" sound, and just dies off altogether. Then I try start it using some throttle and without choke and it seems to flood itself as it doesn't start up straight away. If I do then get it started after churning with my foot on the throttle, it poos itself and won't rev up, sometimes a puff of smoke.
Has anyone got any suggestions before I go out spending money on leads etc?
Thanks
novaguy08
26-03-09, 09:34 AM
Had a similar problem with my inj one........ check leads, plugs, rotor arm and cap..
sounds like your getting a dodgy spark in there......
Did you change the distributor cap and rotor arm as well?
No rj but I think I may have two spare used distributors in the attic that I could try rotor arm and cap off. I will see when I get home.
It happened a little bit when starting last night too but not as bad. Once I finally got it going, it done a 40 mile trip, with just the regular hesitations and chugs. The fact that it goes a little better when warm would point to what you guys suggested would it?
Checked dizzy cap and rotor arm, seems ok, I sanded the points.
The car seems to give a lot of bother when starting from cold... but it goes a bit better when its warm. It won't cut out or anything when its warm but you do notice the odd miss/loss of power!
See if this is understandable: Ok, try the choke, then it cuts out. Then try starting it without choke, no luck. So start with no choke, but with throttle in full, it eventualy starts up but struggles and bogs down, and pops. Then after a few seconds it will rev up.
A mate has said that maybe its not getting enough petrol if it doesn't like the choke.
Another said maybe blocked jets, so try some redex or similar in the fuel.
Also suggested that it could even be timing.
It seems to soot up plugs quite easily.
With any luck we will have a look later if I go to my mates but we are pissing in the wind!?!
novaguy08
26-03-09, 09:30 PM
try redex, no harm, but i would change the leads......... could be a case that the silicone has got damaged somewhere and is either causing a short (lead to heatsheld to the head) or is a loose connection.
As i said i had similar problem with my inj nova 1200 and leads rotor and cap change later all gone, come back 6 months later changed the leads went away!
The plugs will soot up due to it being ran cold/on choke.
Although im presuming your cleaning the plugs now and then while diagnosing the problem(s)? My baby xe ran rubbish untill i cleaned the plugs lol
jimbob-mcgrew
27-03-09, 01:14 AM
if its sooting plugs it might be overfueling, check the choke butterfly is fully dis-engaged on the carb too, might need to lubricate the hinges or adjust the cable if not.
once its warm.. does it idle high ? might be carb settings if so ?
like most have said : rotor arm and dizzy cap too, and check the airbox hot air feed flap, might be stuck or sticking causing it to swallow hot or cold air constantly.
Normally they only run bad due to lack of service, the engines themselves are virtually indestructable. Mine recently had new plugs,leads rotor arm, dizzy cap and took it to the garage as the carb settings were miles off and they also adjusted the timing.
Since then it has run faultlessly, mine did have a loss of power on half throttle which was later traced to there being about a litre too much oil in the engine! lol lol lol
From cold mine doesnt like running too well initially but I give it a 1/4 choke turn the key and about 1/4 on the throttle for five to ten seconds and leave it to tick over till warm. All carb engines have their own way of starting from cold, you just have to figure it out! lol
novaguy08
27-03-09, 06:23 AM
oh and another thing, get a can of carb cleaner and give the carb a clean till its spotless, did this and it helped!
Some replies people:
AW06 - Yeah I am giving the ends of the plugs a sanding every now and again! Although I was told that once a set of plugs have been badly sooted up a few times they won't perform as well?
jimbob-mcgrew - Once its warm it idles at about 800 rpm, as it was set for emissions for mot a week ago. It has been tuned for emissions but always seems to have this little hesitation. My mates 1.2 carb Nova runs more smoothly, more like an injection car. Jimbob I've got a K&N on the carb, so no airbox. However, I can lay my hands on an airbox if you think this might help?
Steve - I've just changed oil/filter/timing belt/plugs, put 3 litres of oil in as haynes recmommend. Perhaps a set of leads wouldn't be a bad idea anyway? Leads would be about 20 quid? How much for new dizzy cap and rotor arm?
novaguy08 - I have already done this when I was putting the engine in. Sprayed it round carb and few blasts down the carb while holding some revs.
**I have noticed why the car hadn't been starting right. I think engaging the choke was what was causing it. I tried starting the car without choke, but with a little throttle, and then just driving off slowly straight away with about 1/4 or 1/3 choke. It started and warmed much better this way! Just got to sort the hesitations etc now.**
Jimbob I've got a K&N on the carb, so no airbox. However, I can lay my hands on an airbox if you think this might help?
Do it, K&N's on 1.2's are crap and often lead to running problems.
**I have noticed why the car hadn't been starting right. I think engaging the choke was what was causing it. I tried starting the car without choke, but with a little throttle, and then just driving off slowly straight away with about 1/4 or 1/3 choke. It started and warmed much better this way! Just got to sort the hesitations etc now.**
That would explain why the plugs were dirty and bad starting, if you're overfuelling on start. I used to find on both my old 1.2s (NV and ST) that you only need a very small amount of choke to start it.
Agreed. I know that the 5door will only start on about 1/4 choke, when somone came to look at it the other day he pulled it right out, and the car stalled lol
Ok so hopefully that is the cause of the plugs sooting up.
I am just wondering should I get a set of leads today aswell. Leads would be about 20 quid should they? Current ones are an unknown age. How much for dizzy cap and rotor arm? Just want an idea.
The car doesn't seem as sharp as when I first fitted the engine though? When I first fitted it, it was very sharp for a 1200, now its not so sharp. It wouldn't have sooted valves in this space of time or anything?
Razorjack I will get the airbox later.
Thanks
Rotor cap and rotor arm are about £13 iirc, Might have to search a few places.
Will probs look into it then. Will try ebay first.
If in doubt, change them. A full service is always a good place to start.
novaguy08
27-03-09, 04:18 PM
Full service and some redex through the engine, leads will be about £20+ I paid £15 from Vauxhall (not genuine tho! even though i thought they were buggers!!) got some a few days ago on a discount for £20 they were direct replacement silicone ones, apparently closest to genuine you can get so cheaper (and by assosiation inferior) parts will be out there, best bet is to try to get some from Vauxhall for it.
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