Club126UK

Fiat 126 Chat => Fiat 126 Mechanical Problem Solving => Topic started by: nathanfiddes on February 04, 2015, 10:03:59 PM

Title: Massive backfire when starting
Post by: nathanfiddes on February 04, 2015, 10:03:59 PM

Hi

My '97 126 can take a while to start. The engine will turn over and over and I can smell fuel at the engine. Then there will be a massive bang! (And I mean massive!!) and it will start fine then.

On acceleration it will back fire slightly here and there.

I also left it running early for about 10mins and it was trying to cut out.

Are all these linked? Is it a carb problem or valve gaps?

It's a later model so has a crank sensor and cool pack.

Thanks

Nath


Sent from my iPhone using Tapatalk

Title: Re: Massive backfire when starting
Post by: 1973/126 on February 04, 2015, 10:11:35 PM

  Sounds like the timing is out. I think there is some adjustment on the crank sensor, so I would start there.
 
 Is the wire attached properly to the carb for the solenoid?

 

Title: Re: Massive backfire when starting
Post by: nathanfiddes on February 05, 2015, 03:18:35 PM

Thanks for the reply. I've had a look at the timing and it seems fine, I can't find any adjustment for the sensor though.

I did fine a leak at the bast of the carb though when the engine is running so I'm guessing this is the issue? I can't tell if it's the gasket between the carb/engine or from somewhere else?

Would this cause popping and backfiring?

(http://tapatalk.imageshack.com/v2/15/02/05/9a8cd7c8a8735e2219bcb67525f49f1d.jpg)


Sent from my iPhone using Tapatalk

Title: Re: Massive backfire when starting
Post by: gammakeith on February 05, 2015, 05:39:43 PM

Backfiring can certainly be due to lean mixture so I think you have found your culprit!

Keith

Title: Re: Massive backfire when starting
Post by: Dibles on February 06, 2015, 03:38:52 PM

Carb related I reckon

Title: Re: Massive backfire when starting
Post by: nathanfiddes on February 06, 2015, 06:49:07 PM

Thanks all. I'll have a look at taking the carb off and cleaning it up.


Sent from my iPhone using Tapatalk

Title: Re: Massive backfire when starting
Post by: nathanfiddes on February 25, 2015, 09:09:35 PM

Well I fixed up the leak at the base of the carb and the backfire has gone now! No more scaring the hell out of everyone around me!

The only other problem is when I Rev the engine it tries to cut out on me and will only run if I push the throttle down more.

Is it running too rich? The cable running to the pedal looks interesting, I'll post a pic tomorrow.

Thanks


Sent from my iPhone using Tapatalk

Title: Re: Massive backfire when starting
Post by: poxxxy on February 26, 2015, 12:20:14 AM

Have you got it up to temperature before giving it throttle? Mine needs to warm up before it behaves anywhere close to normal when I blip the throttle...

Title: Re: Massive backfire when starting
Post by: nathanfiddes on February 26, 2015, 11:45:09 AM

Probably not as I have only driven on really short journeys around the car park at work, I sense it will still do the same when it's warm though but I'll give it a try warmed up.

Thanks


Sent from my iPhone using Tapatalk

Title: Re: Massive backfire when starting
Post by: poxxxy on February 26, 2015, 01:57:38 PM

Same with the choke on full?

Title: Re: Massive backfire when starting
Post by: nathanfiddes on February 28, 2015, 09:45:33 PM

Yeah it is, it sounds like it's running too rich to me, I guess I'll have a look at it next week.


Sent from my iPhone using Tapatalk