Engine Misfire

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Wodza
Posts: 12
Joined: Fri Sep 22, 2017 1:18 am
Your car is a: 1973 Fiat Spider

Engine Misfire

Postby Wodza » Mon Sep 25, 2017 9:56 am

Just bought a 1973 spider on the 17th. Ive been driving it around quite a bit since getting it and it has been running really well. Yesterday on my drive to the cottage I started to notice an occasional misfire (short and temporary loss of power no loud bang or knock) while driving at a constant highway speed. I opened the hood to make sure the spark plug wires were firmly attached to the plugs and although one seemed loose there was no change after making sure it was tightly snapped on. I made the drive home and still had the occasional misfire but then found the car having a hard time at idle as well which it was not having before. Once I got home I parked it, slept and took my other car to work where I am now typing this so I haven't had a chance to look at it further. I thought i would write up on here to see where I should start. I don't have much experience working on cars so I am looking for advice on what I should check first and which order I should move on. From what I've been able to look up it seems like checking the spark plugs is numbers one. The lady I bought the car off of said she had just had them replaced so they are probably pretty new. If the plugs seem to be fine what is the next thing I should check?

Also, as this may be pertinent information, what I think is the ground coming of the ignition coil seems to be loose. Is this something that would cause an occasional misfire?

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seabeelt
Patron 2019
Patron 2019
Posts: 1612
Joined: Tue Feb 19, 2008 4:22 pm
Your car is a: Fiat Spider - 1971 BS1
Location: Tiverton, RI

Re: Engine Misfire

Postby seabeelt » Mon Sep 25, 2017 12:39 pm

Plugs, wires, points, rotor, cap
Michael and Deborah Williamson
1971 Spider -Tropie’ - w screaming IDFs
1971 Spider - Vesper -scrapped
1979 Spider - Seraphina - our son's car now sold
1972 Spider - Tortellini- our son's current

Wodza
Posts: 12
Joined: Fri Sep 22, 2017 1:18 am
Your car is a: 1973 Fiat Spider

Re: Engine Misfire

Postby Wodza » Mon Sep 25, 2017 1:46 pm

Thanks

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kilrwail
Posts: 1099
Joined: Wed Mar 04, 2009 6:49 am
Your car is a: 1978 Fiat 124 Sport Spider
Location: Perth, Ontario

Re: Engine Misfire

Postby kilrwail » Mon Sep 25, 2017 2:29 pm

Always start with the free repair. That loose wire on the negative post of the coil is NOT a ground. It is the place where the points in the distributor signal the coil that it is time for a high voltage spark to be sent to the spark plugs. Clean it and tighten it before spending a nickel!
_____________________________________________________________
Peter Brownhill

1978 Fiat 124 Sport Spider - original owner
1977 Porsche 911S - track car
2022 Ram 4 x 4 - hauler
PCA National Instructor and Motorsport Safety Foundation Level 2 Instructor

Wodza
Posts: 12
Joined: Fri Sep 22, 2017 1:18 am
Your car is a: 1973 Fiat Spider

Re: Engine Misfire

Postby Wodza » Mon Sep 25, 2017 3:05 pm

Will do! thanks


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