Small backfire on over-run

[dollydimple2]

My 1993 300ce has recently developed an annoying little backfire when I lift my foot off the accelerator.
It’s an almost imperceptible POP ! but it’s definitely there and I’m worried it will damage the exhaust or any thing else.
Someone said it could be the MAF going out allowing unburnt fuel to gather there but whilst I know it’s not an expensive place to start I’d much rather have some advice from someone who’s experienced this sort of problem before, thanks for any tips in advance. Dolly.

 

[whitenemesis]

And to think some would pay to have pop and crackle on the over-run!
Check for air leaks in the exhaust manifold and joints. Check ignition timing

 

[dollydimple2]

And to think some would pay to have pop and crackle on the over-run!
Check for air leaks in the exhaust manifold and joints. Check ignition timing

Thx for the advice. Dolly

 

[Bellow]

Exhaust leak is a possibility - as is slight overfuelling eg, a dribbling injector (if L-type).
My car did the same until I dialled back the amount of fuel on over-run.

 

[dollydimple2]

Exhaust leak is a possibility - as is slight overfuelling eg, a dribbling injector (if L-type).
My car did the same until I dialled back the amount of fuel on over-run.

Good Morning, I wonder what’s involved in
“ dialling back the fuel “ . I’ve read up on the Kjetronic system but would be dead-scared to touch it , maybe that’s not what was involved when you had the problem but thanks for the reply.Dolly

 

[Bellow]

Good Morning, I wonder what’s involved in
“ dialling back the fuel “ . I’ve read up on the Kjetronic system but would be dead-scared to touch it , maybe that’s not what was involved when you had the problem but thanks for the reply.Dolly

Me 'dialling back fuelling' was on an LPG system on a Chevrolet V8 - definitely not appropriate here. You have answered my question I didn't ask though ie which fuel system you have - K-Jetronic. It doesn't have a MAF sensor as we recognise them but its metering plate may possibly be a touch slow (sticking) in returning to its closed position when you release the throttle. That I'd guess would let it behave like my Chevy did and over-fuel slightly until it closed.
Any other symptoms? Any hesitancy on opening the throttle?

 

[BlackC55]

Its probably a mixture issue. They dont have a "MAF" as such. Do you run any fuel cleaner ever? Has the injection system ever been over hauled?

 

[dollydimple2]

Me 'dialling back fuelling' was on an LPG system on a Chevrolet V8 - definitely not appropriate here. You have answered my question I didn't ask though ie which fuel system you have - K-Jetronic. It doesn't have a MAF sensor as we recognise them but its metering plate may possibly be a touch slow (sticking) in returning to its closed position when you release the throttle. That I'd guess would let it behave like my Chevy did and over-fuel slightly until it closed.
Any other symptoms? Any hesitancy on opening the throttle?

Thx again for the response, I’m clearly confused about the MAF situation, I’ll check the movement of the metering plate.
The slight POP on over- run is the only problem ,starts first time hot or cold especially since changing the camshaft positioning sensor.

 

[dollydimple2]

Its probably a mixture issue. They dont have a "MAF" as such. Do you run any fuel cleaner ever? Has the injection system ever been over hauled?

Hi and thx for the advice, in answer, I don’t run fuel cleaner as such but do add a product to keep fuel stable , I keep the car in France so it doesn’t get much use and no the injection system hasn’t been overhauled in my ownership. The car is in rural Brittany and I’ve never found anyone able to take care of it, wish
I lived near Pompey. Would you recommend a fuel cleaner? would injector cleaner help?