Backfire on overrun

Discuss mechanical problems here.

Moderator: Moderators

James k
Minor Fan
Posts: 478
Joined: Tue Nov 11, 2014 3:59 pm
MMOC Member: No

Backfire on overrun

Postby James k » Sun Sep 08, 2019 3:12 pm

Hi,
I'm getting quite a lot of backfire on overrun, for example when going down a fairly steep hill in third gear. What could be the cause of this and is it typical? I am talking about popping and not the classic Morris Minor overrun noise or exhaust parp.

Thanks,
James

Myrtles Man
Minor Addict
Posts: 561
Joined: Wed May 16, 2018 10:49 pm
MMOC Member: Yes

Re: Backfire on overrun

Postby Myrtles Man » Sun Sep 08, 2019 4:54 pm

Leak in exhaust?

Online
mobylette
Minor Fan
Posts: 138
Joined: Sat Feb 13, 2010 5:02 pm
MMOC Member: Yes

Re: Backfire on overrun

Postby mobylette » Sun Sep 08, 2019 6:18 pm

0
Last edited by mobylette on Sun Sep 08, 2019 6:18 pm, edited 1 time in total.

Online
mobylette
Minor Fan
Posts: 138
Joined: Sat Feb 13, 2010 5:02 pm
MMOC Member: Yes

Re: Backfire on overrun

Postby mobylette » Sun Sep 08, 2019 6:18 pm

+1 for exhaust leak. Cast an eye over the entire exhaust system and see if you can spot any witness marks to show where exhaust gases are escaping , usually at a joint.

kennatt
Minor Legend
Posts: 2339
Joined: Fri Feb 02, 2007 9:11 pm
MMOC Member: No

Re: Backfire on overrun

Postby kennatt » Mon Sep 09, 2019 9:56 am

check the timing probably slightly retarded

myoldjalopy
Minor Legend
Posts: 1134
Joined: Tue Jan 29, 2013 10:32 pm
MMOC Member: Yes

Re: Backfire on overrun

Postby myoldjalopy » Mon Sep 09, 2019 11:23 am

It could be any number of things in addition to those mentioned above - faulty plugs, wrongly set points gap, failing condensor, weak fuel mixture, sticking valves......to mention just a few. Are all leads and connections on the ignition system secure? Have you altered/adjusted/changed anything recently - which might be a clue?

James k
Minor Fan
Posts: 478
Joined: Tue Nov 11, 2014 3:59 pm
MMOC Member: No

Re: Backfire on overrun

Postby James k » Tue Sep 10, 2019 1:06 pm

Hi,
Thanks for the replies. I did change the head gasket a few months ago so the exhaust has been disturbed. I'll check the joints. The ignition and fuel systems have been checked over recently and are all in order.

Thanks,
James


Who is online

Users browsing this forum: philthehill and 10 guests