Eugene Posted June 19, 2009 Share Posted June 19, 2009 My new Zetec is great, but has started popping and banging through the exhaust and carbs on low throttle settings/slow speeds. The idle revs can also be variable when coming off the throttle without warning, and often the revs don't drop immediately, and the engine has even stalled at a junction... I've not had a chance to have a fiddle as I'm just back from the railway stn., but thought I'd post this quick question to see if there are any ideas before I start pulling things to bits... It has to be an easy problem as all has been running well, but I'm only just into the running-in period, so no rolling road just jet! Leaking air around the carbs? Wrong jets? Any other ideas??? Thanks in advance, Steve Small Boy - with Loud Toy! See Eugene here and see what I do here Link to comment Share on other sites More sharing options...
rj Posted June 19, 2009 Share Posted June 19, 2009 When it's popping and banging it's usually running lean. If idle is erratic too I'd start by checking for air leaks... Link to comment Share on other sites More sharing options...
Eugene Posted June 20, 2009 Author Share Posted June 20, 2009 That's what I thought - just about to go out to the garage and have a play, so will report back later. Small Boy - with Loud Toy! See Eugene here and see what I do here Link to comment Share on other sites More sharing options...
millsn Posted June 20, 2009 Share Posted June 20, 2009 Long shot but check the exhaust manifold flanges where it meets the head. The weld here can fail making the car run poorly. esp if it was difficult getting the whole lot to line up, erhem Edited by - millsn on 20 Jun 2009 11:45:05 Link to comment Share on other sites More sharing options...
Eugene Posted June 20, 2009 Author Share Posted June 20, 2009 It seems to have been a combination of air leaking around the carbs and lean set idle jetting... Lots better now, with stable idle revs, and less popping and banging - although some. Good enough until I get to the rolling road session 😬 Boy, is it great to drive! Small Boy - with Loud Toy! See Eugene here and see what I do here Link to comment Share on other sites More sharing options...
JACK FLASH Posted July 14, 2009 Share Posted July 14, 2009 Guys, What is the definition of popping and banging? Other words I hear a lot are spitting and couching. Can anyone enlighten this terminology since I am also fiddling with the carbs of my Twin Cam and it is always nice to be able to describe the observations correctly? Jack Flash Link to comment Share on other sites More sharing options...
Normans_Ghost Posted July 14, 2009 Share Posted July 14, 2009 Popping and banging with flames (usualy only sen at night) is due to overfuelling from Weber carbs. The excess fuel collects in the silencer and then explodes making a loud bang and shooting a flame from the exhaust. In most cases there's nothing actually wrong. Doesn't happen on injected engines as the fuel is shut off on the overrun. be careful about overtightening the carbs. They're supposed to be flexible to stop fuel frothing at high revs. I've had people tell me the carbs are letting in air because when they move the carbs up and down the revs rise. I show them that they are opening the throttle as they yank upwards and this is why the revs rise. Norman Verona, 1989 BDR 220bhp, Reg: B16BDR, Mem No 2166, the full story here You and your seven toThe French Blatting Company Limited Link to comment Share on other sites More sharing options...
MADMALC Posted July 14, 2009 Share Posted July 14, 2009 Not convinced that my SLR fuel is cut off on the over run. Do it? or don't it? Look forward to the answer from those that wat know these things. S7MAD Link to comment Share on other sites More sharing options...
Racing Snake Posted July 14, 2009 Share Posted July 14, 2009 Lots of popping and banging with injection on over run ! Mad Hatter Racing - Feel The Duralight R Torque 😬 Carl Van Baars Link to comment Share on other sites More sharing options...
Martin J Posted July 14, 2009 Share Posted July 14, 2009 My Sigma 7 pops & bangs on the overrun & I love it 🥰 Link to comment Share on other sites More sharing options...
Ray Pearce Posted July 15, 2009 Share Posted July 15, 2009 On the Emerald ECU software there is a check box to turn overrun popping and banging on and off 😬 Link to comment Share on other sites More sharing options...
Doug Posted July 15, 2009 Share Posted July 15, 2009 Glad you love your Zetec so much, they really are fabulous engines and seem to work very well indeed in a Seven. I wouldn't change mine for anything 🥰 'Have you any idea what it's like to have the wind rushing through your hair!' (Quote:Sq Cdr the Lord Flashheart) Link to comment Share on other sites More sharing options...
JACK FLASH Posted July 16, 2009 Share Posted July 16, 2009 Guys, So the summarize it, some poppi g and banging in the exhaust of a Weber fuel fed car is normal but when it gets too much the idle setting is too lean. Correct ? Jack Flash Link to comment Share on other sites More sharing options...
Normans_Ghost Posted July 16, 2009 Share Posted July 16, 2009 I would say too rich. The popping and banging is fuel in the silencer exploding. If the fuel isn't shut off on the overrun of a 7 then its been disabled as it's normal on an ECU managed car to do this. Norman Verona, 1989 BDR 220bhp, Reg: B16BDR, Mem No 2166, the full story here You and your seven toThe French Blatting Company Limited Link to comment Share on other sites More sharing options...
Drumster Posted July 16, 2009 Share Posted July 16, 2009 Popping and banging with flames (usualy only seen at night) Ah, those were the days before Powerspeed sorted out the air leak between the primaries and the collector 😔 Chris Alston C7CAT 1800 Supersprint R248 ....and then I jumped in Link to comment Share on other sites More sharing options...
Area Representative RussG Posted July 17, 2009 Area Representative Share Posted July 17, 2009 My Sigma 150 used to pop and bang on the overun but the latest re-map has cured it. A shame really because it sounded great. Russ *wavey* Link to comment Share on other sites More sharing options...
P150NR Posted July 17, 2009 Share Posted July 17, 2009 My Sigma 150 used to pop and bang on the overun but the latest re-map has cured itMines going in next month so now Im sad ☹️ Mal Stubbs Link to comment Share on other sites More sharing options...
Area Representative RussG Posted July 17, 2009 Area Representative Share Posted July 17, 2009 Mal, Maybe you could ask the nice people at Caterham to do the re-map and leave the pops and bangs intact. Seriously though it is a big improvement. Russ Link to comment Share on other sites More sharing options...
Steve C Posted July 25, 2009 Share Posted July 25, 2009 Stopping the popping, banging and flames? 'Wet the Webers, light them and blat!' Link to comment Share on other sites More sharing options...
Normans_Ghost Posted July 25, 2009 Share Posted July 25, 2009 Steve, The weber's are at the other end! Norman Verona, 1989 BDR 220bhp, Reg: B16BDR, Mem No 2166, the full story here You and your seven toThe French Blatting Company Limited Link to comment Share on other sites More sharing options...
Drumster Posted July 26, 2009 Share Posted July 26, 2009 *arrowup* 😬 Chris Alston C7CAT 1800 Supersprint R248 ....and then I jumped in Link to comment Share on other sites More sharing options...
The Boy Posted July 26, 2009 Share Posted July 26, 2009 My 150 Sigma has just had the new map. Not had a propper blat yet just a drive back from Caterham - motorway driving is much improved 😬 Couldn't resist getting shift light fitted while it was in Learning new skills all the time, 10000 miles completed. Link to comment Share on other sites More sharing options...
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