help with misfiring Metro

Post your technical queries / problems here!
Message
Author
PaulTugwell
Posts: 5
Joined: Tue Jul 07, 2015 9:30 am

help with misfiring Metro

#1 Post by PaulTugwell » Tue Jul 07, 2015 9:44 am

My friend owns an immaculate 1988 Metro City 1.0L.
The car has an annoying problem which I am struggling to resolve and I am wondering if anyone has any suggestions. The car runs fine for at least 30 minutes, sometimes longer, then it will start to misfire quite badly. Stopping and waiting for a while usually cures the fault. It can also be brought on by parking the car for around 5 minutes after a reasonable run. These symptoms lead me to believe it is a temperature related problem. I should also add that we do have a lot of spares from another Metro which was written off. Both cars have done less than 30000 miles.
To attempt to fix this I have fitted new plugs, points and condenser. I have also swapped the coil, distributor, carburettor and fuel pump from the other car which was running fine until its accident. I also re-routed the fuel pipe away from the exhaust system and fitted an inline filter.
I have also checked the engine compression and valve clearances and both are fine.
None of the above had any effect on the fault. One final thing having fitted the inline filter I do notice that there is the occasional bubble in the fuel line and this seems to increase with time.
I am now at a bit of a loss as to what to do next so would appreciate any suggestions.
Thanks
Paul

User avatar
Luxobarge
Posts: 1780
Joined: Wed Jan 05, 2011 3:12 pm
Location: Horne, Surreyshire

Re: help with misfiring Metro

#2 Post by Luxobarge » Tue Jul 07, 2015 10:06 am

Welcome to the forum!

Have you tried swapping HT leads?
Some people are like Slinkies - they serve no useful purpose, but they still bring a smile to your face when you push them downstairs.

PaulTugwell
Posts: 5
Joined: Tue Jul 07, 2015 9:30 am

Re: help with misfiring Metro

#3 Post by PaulTugwell » Tue Jul 07, 2015 10:21 am

Hi Yes I forgot to list those, the HT leads have also been changed

Fatbloke
Posts: 381
Joined: Mon Apr 14, 2014 3:50 pm
Location: Royal Wootton Bassett

Re: help with misfiring Metro

#4 Post by Fatbloke » Tue Jul 07, 2015 10:38 am

Could it be a fuel evapouration problem? is there the correct heat sheild around the carb?

(Just a thought and fully prepared to be shot down in flames as the incompetant bumbling fool that I am! :oops: )
Mike.

A Fatbloke in a Herald

suffolkpete
Posts: 1054
Joined: Sun Jan 23, 2011 11:54 am

Re: help with misfiring Metro

#5 Post by suffolkpete » Tue Jul 07, 2015 10:49 am

Have you changed the rotor arm? Black ones are often of questionable quality. Also, is the fuel tank venting correctly, there could be a vacuum building up as fuel is drawn off. Next time it stops, remove the filler cap and see if that cures the problem.
1974 Rover 2200 SC
1982 Matra Murena 1.6

PaulTugwell
Posts: 5
Joined: Tue Jul 07, 2015 9:30 am

Re: help with misfiring Metro

#6 Post by PaulTugwell » Tue Jul 07, 2015 11:44 am

Hi

The rotor arm has been changed, admittedly for another black one but it would be very unlucky if it had exactly the same problem.

I too thought it could be fuel evaporation, there is a heat shield fitted which shields the carb from the block but heat could still rise from under the carb (which is above the exhaust manifold)
However as the car appears to be totally standard if this was the problem then all the other remaining metro's should be suffering similarly, which as far as I am aware they don't (although if anyone knows differently I would be very interested to hear).

The non venting tank was also considered, however as removing the filler cap does not immediately resolve the issue I had discounted that.

Regards

Paul

Classic Microcars
Posts: 71
Joined: Sun Sep 14, 2014 7:06 pm

Re: help with misfiring Metro

#7 Post by Classic Microcars » Tue Jul 07, 2015 1:13 pm

Fuel tank breather blocked? Open the cap when it packs up and you might get a whoosh as the air rushes in.

User avatar
eddypeck
Posts: 50
Joined: Thu Jun 04, 2015 1:05 pm

Re: help with misfiring Metro

#8 Post by eddypeck » Tue Jul 07, 2015 2:07 pm

Hi,
Totally clutching at straws as I have no idea on the set up of these cars. But I'm wondering if it's an auto choke with some kind temp control such as a wax stat or bi-metallic strip to adjust the fueling once warm.

It certainly sounds like it's an issue as the temp rises and the car needs to cool again.

I hope you get it sorted soon enough. I've had ongoing fueling issues with my car, I know how frustrating it is.
1986 VW Golf GTi, 1988 VW Golf GTi, 1993 BMW e30 318i Touring Lux

User avatar
TerryG
Posts: 6750
Joined: Wed Jan 05, 2011 1:54 pm
Location: East Midlands

Re: help with misfiring Metro

#9 Post by TerryG » Tue Jul 07, 2015 3:38 pm

It could still be fuel evaporation. My Morris Minor used to do it until I installed a head shield which fixed the problem apart from on re-start after a long-ish run (eg stopping in motorway services then trying to drive off again), exhaust wrap on the manifold fixed that completely and very cheaply. You could also have a minor leak between the manifold and downpipe raising the temp for the carb even more.
Does your metro have the mechanical or electric fuel pump? I have had problems with mechanical pumps on 1275 minis that really don't like working when hot or at high load. Swapping to an electric one is a cheap and easy fix (don't leave the mechanical one in your engine or it will fly apart and break your diff (don't ask me how I know this)).
Understeer: when you hit the wall with the front of the car.
Oversteer: when you hit the wall with the back of the car.
Horsepower: how fast you hit the wall.
Torque: how far you take the wall with you.

User avatar
Luxobarge
Posts: 1780
Joined: Wed Jan 05, 2011 3:12 pm
Location: Horne, Surreyshire

Re: help with misfiring Metro

#10 Post by Luxobarge » Tue Jul 07, 2015 3:57 pm

Good thread this.

Moved into "Technical Queries", as that's what it is, and it'll get more appropriate views there.

Cheers! :D
Some people are like Slinkies - they serve no useful purpose, but they still bring a smile to your face when you push them downstairs.

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest