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Thumpin around...


AlexJames
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Hey guys,

 

Just gone BPU, the engine is running kinda wierd, there is only what I can describe as thumps from the exhaust when it runs idle. It runs fine when the auto choke is kickin in, but then it drops to about 500rpm on idle... it doesnt sound like a miss fire cause I had on accleration that when I took the cats out and didnt change the sparks... lol

 

I assumed it was down to the ECU having to re-compensate due to the lack of back pressure but after almost a week its still doing it...

 

Did I change to the wrong sparks? I have Bosche (or however u spell it) sparks with at least a 0.7 gap. I have them the product code for the NGK sparks and they matched them with these... bad idea?

 

Or is it the fact that I havent put the walbro fuel pump in yet? :search:

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If you now have a free flowing exhaust you are prob just hearing the normal idle, its been talked about on here in the past.

 

Is it like a little miss every few revolutions?

 

Homer might be able to describe it better than me as we talked about it before.

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If you now have a free flowing exhaust you are prob just hearing the normal idle, its been talked about on here in the past.

 

Is it like a little miss every few revolutions?

 

Homer might be able to describe it better than me as we talked about it before.

 

Yeah thats what it sounds like.. although sometimes the idle drops below 500 rpms and sounds like its about to stall, sometimes at a junction if I hammer the clutch down fast and break.. it does stall.. which is embarassing lol

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Yeah thats what it sounds like.. although sometimes the idle drops below 500 rpms and sounds like its about to stall, sometimes at a junction if I hammer the clutch down fast and break.. it does stall.. which is embarassing lol

 

That could be a sticky idle valve, but the thumping is normal.

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  • 1 year later...
Yeah thats what it sounds like.. although sometimes the idle drops below 500 rpms and sounds like its about to stall, sometimes at a junction if I hammer the clutch down fast and break.. it does stall.. which is embarassing lol

 

Classic overfuelling symptoms. What have you monkeyed with? :) It's a j-spec right? So a vent-to-atmo BOV won't be causing this. Mucky O2 sensor possibly - check the ox1 pin in the diagnostics port for voltage when the car is warm idling, should bounce around .5v

 

The occasional blap out the exhaust on idle is a feature of closed loop testing the limits. Relax, the mkIII used to do it too :)

 

-Ian

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