Backfiring! Could it be related to a recent alternator belt replacement?

jpjeep26uk

YJ Enthusiast
Joined
Nov 12, 2022
Messages
181
Location
UK
Hi, Newbie here so please let me know if Ive posted in the wrong place!
I've never had a peep from my Jeep - driven close to 2000 miles across the UK since getting it in July. Last week I took it to my local garage (not a Jeep specialist- they are hard to come by around here:oops:) to replace the Alternator Belt, the PAS belt and to replace a weeping Trans Output seal.
Drove about 4 miles and woah! BANG tastic!
Backfiring all over the place. Never done it at all before and not a peep from the engine in any other way.
Could it be related to the belt changes or just coincidence?
No loss of power, just sounds like its going to stall upon start up and then backfiring when i slow down from speed. Usually preceded by a sort of flapping/ whapping sound at the back then 3 secs later....... KABOOM!!

Any ideas before I take it back to the garage and ask them to sort it out?
Many thanks.
JPJeep26
 
Id guess the shop knocked a vac line or sensor wire off while doing the belt. I cant think of any other logical explanation.
Hi, I checked to see if anything had been nudged or knocked and couldn't see anything. Very odd. I had the tyres balanced straight after at a tyre place and I'm wondering now if they caught something whilst jacking it up. Fuel lines or something. Maybe crimped something. Really driving me nuts !
 
Hi sorry, it's a 2.5 from late 1988. I'm not sure how to check the firing but I have a manual so I'll give it a go. Thanks.

I forgot you said you got down the road a piece...If it was the firing order it would have reared it's ugly head at start up.....Check your fuel filter and flow...
Is it carbureted or fuel injection? A "Leaning" Out of the fuel feed could cause this very problem.....
 
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I forgot you said you got down the road a piece...If it was the firing order it would have reared it's ugly head at start up.....Check your fuel filter and flow...
Is it carbureted or fuel injection? A "Leaning" Out of the fuel feed could cause this very problem.....
I've ordered new fuel filter as I thought it might have been damaged during a tyre balancing session and it looked years old!

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Have you given it a basic tune up? Plugs, wires, etc.
hi, I'm in the process of buying the stuff needed for that today, tubing, fuel filter, plugs, dist cap, vent valves, etc. I may try to do that TDC / rotor thing as well. It's not a quick process to get all this stuff in the UK as it's simply too old and Canadian / American so a lot of it has to be imported. Gets expensive! Hopefully when all this had arrived and fitted and tweaked it'll run fine again. I may even drop the tank and see if it's cruddy and also check out the pump and tubes. I'm new to all of this so it's not my usual area of tech! Fender Stratocaster yes, Jeeps? Haha , no sir!
 
hi, I'm in the process of buying the stuff needed for that today, tubing, fuel filter, plugs, dist cap, vent valves, etc. I may try to do that TDC / rotor thing as well. It's not a quick process to get all this stuff in the UK as it's simply too old and Canadian / American so a lot of it has to be imported. Gets expensive! Hopefully when all this had arrived and fitted and tweaked it'll run fine again. I may even drop the tank and see if it's cruddy and also check out the pump and tubes. I'm new to all of this so it's not my usual area of tech! Fender Stratocaster yes, Jeeps? Haha , no sir!
Also, I've got the harness manual which us handy and another member kindly sent me the technical manual so I'm reading the heck out those haha but if you have tips on tuning then feel free to share as I'm not sure replacing all these bits constitutes a 'tune up'? More like a 'fix bits that look old and may be causing misfire'