14 replies to this topic

[KingCraig]

1. 1987
2. Park lane With an A+ MG Metro 1275 and Hif44 (not 100% on carb size)
3. Idles fine if not a tad high at about 1100 -1250tops the problem comes when adding acceleration in neutral its not so bad the misfire is slightly present but not too noticable but when a gear is engaged there is a distinct popping type misfire coming from the carb and a lack of power throughout the rev range. The effects are amplified the more acceleration you give it. Ive had the air filter (K&N Cone) off and when given acceleration in neutral it appears to spit a white mist out (fuel?) Ive checked and replaced all the spark plugs had the dizzy cap off and given that a clean and made sure its dry, the connections in there look a tad corroded(will this effect the spark?) Dashpot oil is fine and is 15/40 the fuel filter has been moved and sits right next to the carb, there is a small amount of sediment gathered in the bottom of it about a quarter the size of a 5p and im using electronic fuel pump and not so sure on the ignition ( how can i tell? )Other than that i cant think of anything else, when i drove back from Doncaster Sunday it ran like a dream, the same evening this problem developed.
4. Set my phone recording while testing after one of the above checks so you can hear the noise and timing yourself

(video currently uploading and due to finish at 23.30 latest)

 

Had a search through here and tried most the answers given any helps tips or a straight up guide would be so very appreciated

 

Craig

[KernowCooper]

Have you compression checked it to rule out a burnt valve/seat or head gasket problems, with it idling over and with insulated pliers pull the leads one by one and see if all 4 cylinders are the same rev drop and doing their bit?

Edited by KernowCooper, 20 May 2013 - 09:33 PM.

[KingCraig]

Yeah checked that, all did the same to the revs, the only reason i've got it idling high is when i had it set close to 1000RMP it would stall occasionally but only while this problem is present, prior the idle was low and no stall.

[Dan]

  Is the dizzy baseplate moving properly?  Nothing has come apart or seized up inside it?

[BenCoul]

Vaccume advance hose in good working order?

Exhaust leaking? or exhuast manifold gasket?

[iwatkins]

Sounds the same as ours. Needed a 1100rpm to avoid stalling and was running lean under load and backfiring through the carb.

Checked all vacuum hoses but that was ok and turned out to be the carb to manifold gaskets had gone. Replaced with new ones and could get a 850rpm idle and could even weaken the mixture and runs lovely now.

Cheers

Ian

[KingCraig]

More information descoved while fiddling at work, when I pull the ht lead from 2 and 3 there is virtually no change in revs at idle, which is new as this was the first thing I checked??
This implies something wrong within the engine then?

Edited by KingCraig, 21 May 2013 - 02:57 PM.

[tarris850]

I had the same problem, although it was on my 850. Turned out to be at least one of the HT leads had started to break down although fairly new , so I replaced the set and it's been fine since.

 

Could this be a possiblity?

[KingCraig]

I'd rather that than the valves, new ht leads tonight

[KingCraig]

Tried everything I could at home but my local mini guy simply said its the head gasket, having that changed today and hopefully there is no damage to the block, head will be re skimmed before going back together

This should fix the issue and will leave this hear for anyone else that has this problem

Craig

[Dan]

  Don't just assume it needs skimming, cast iron heads don't often warp.  Measure it properly first.

[KingCraig]

Righto, I trust the guys I've got it with that he will do so and skim only if needed

[Badboytunes]

I always skim a head , its not expensive and at least its done.

 

Just out of curiousity did you try an new dizzy canp ( i know you said you cleaned the one fitted ) and did you change the condensor , if fitted?

 

 

Cheers

[Captain Mainwaring]

Push the button on the handbrake when applying..........

You could compression test it....

Though it does sound like a blow between two pots.

I wouldn't skim a head that was straight. Pointless exercise.

[KingCraig]

No I kept the dizzy that was on there, compression test showed it was a blow between 2 and 3. The thinking is that the gasket has probably blown because of a warped head?
Like I said before he will most Likely only skim the head if it needs it
Cheers Guys!