hodge Posted June 5, 2012 Share Posted June 5, 2012 Hi guys What sort of symptoms will I experience if my plugs are goosed with a single turbo'd supra. My wideband sensor is in my midpipe so because the spark plug isnt sparking as it should, will this cause my AFRs to go lean and missfire on boost. Or am I way off the mark here. Cheers John Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted June 5, 2012 Share Posted June 5, 2012 If you werent sparking properly it would be indicating rich I would assume. When were they last changed, what grade are they? Quote Link to comment Share on other sites More sharing options...
hodge Posted June 5, 2012 Author Share Posted June 5, 2012 If you werent sparking properly it would be indicating rich I would assume. When were they last changed, what grade are they? There grade 8s. Still copper plugs I had the car dyno'd with. They've done about 2K. I've got a set of iridium plugs to go in but I don't want to chuck um in if I have a fueling issue cos I'll melt something. Think I've got a spare set of mapping plugs I'll chuck in n see what happens. Will post some pics up of the tips. Quote Link to comment Share on other sites More sharing options...
absz Posted June 5, 2012 Share Posted June 5, 2012 Have you checked for Vaccum leaks especially around the fuel pressure regulator. Quote Link to comment Share on other sites More sharing options...
mellonman Posted June 5, 2012 Share Posted June 5, 2012 maybe put up whats happening and someone might be able to tell you what it is,as swampy said i would expect the afrs to go rich with the unburnt fuel Quote Link to comment Share on other sites More sharing options...
Andy Blyth Posted June 5, 2012 Share Posted June 5, 2012 Hi guys What sort of symptoms will I experience if my plugs are goosed with a single turbo'd supra. My wideband sensor is in my midpipe so because the spark plug isnt sparking as it should, will this cause my AFRs to go lean and missfire on boost. Or am I way off the mark here. Cheers John If a cylinder misfires, there will be an excess of oxygen in the exhaust (as it has not been consumed by combustion with fuel). If there are enough misfires together, a wideband lambda (oxygen) sensor will tend to read towards the lean end of the scale. A lean reading could very well be the result of iffy spark plugs. Quote Link to comment Share on other sites More sharing options...
hodge Posted June 5, 2012 Author Share Posted June 5, 2012 I've just pulled the plugs and they dont look too bad if I'm honest. I'll upload a pic of the tip in a bit. The car runs perfect off boost, but as soon the turbo starts to spool 0.3 bar ish, it splutters and the AFRs go off the scale lean on my wideband. I've got a brand new set of NGK racing plugs there, I'll stick them in and see what happens. I didn't really want to use these until I'm back to the Dyno though incase I fowl them cos there 240 quid a set Quote Link to comment Share on other sites More sharing options...
mellonman Posted June 5, 2012 Share Posted June 5, 2012 could this be a a injector sticking, best to stick the plugs in and see but take it easy just to see if it stop the miss, but if its still lean then stop but to be fair 0.3 bar of boost would still be pritty lean on part throttle Quote Link to comment Share on other sites More sharing options...
hodge Posted June 5, 2012 Author Share Posted June 5, 2012 Here we go. Plug doesn't look too bad. Quote Link to comment Share on other sites More sharing options...
hodge Posted June 5, 2012 Author Share Posted June 5, 2012 could this be a a injector sticking, best to stick the plugs in and see but take it easy just to see if it stop the miss, but if its still lean then stop but to be fair 0.3 bar of boost would still be pritty lean on part throttle It drives perfectly off boost. I'll swap the plugs and inversigate a little more tonight. Can't test drive it today now cos the heavens have just opened Quote Link to comment Share on other sites More sharing options...
Wez Posted June 5, 2012 Share Posted June 5, 2012 I had similar issue, turned out to be dodgy coil pack connector. Could also be a dodgy coil pack, speak to Ryan as the Syvecs could tell you what cylinder is having issues Quote Link to comment Share on other sites More sharing options...
letmeshowyou Posted June 5, 2012 Share Posted June 5, 2012 Personally, I'd say don't put the other plugs in. Iridiums can't really be cleaned right? Get some cheapy copper ones for testing purposes if you think that's what it is. Quote Link to comment Share on other sites More sharing options...
hodge Posted June 5, 2012 Author Share Posted June 5, 2012 I'm now thinking its been an air leak in the fuel system. I've put my new plugs in cos I know theres no issues with them. I say an air leak because I noticed when the pumps prime without me starting the car, my fuel pressure goes upto 3 bar. When the pumps turn off, my pressure would drop rapidly to zero. Now I've got 2 check valves in there, 1 from each pump just outside the hanger so the lines should hold some sort of pressure. So I decided to strip down the front of the fuel system filter forwards and see what I could find. I did find the rear of the fuel filter was not very tight, enough to stop the fuel coming out under pressure but it maybe was sucking a little air too. I've cleaned the filter out and tightened everything up super tight. I also going the o-ring on the FPR feed from the rail was perished, again a possible pressure leak culprit. I decided to replace all the O-ring and check all the connections. It all went back together and after priming, my fuel pressure drops a lot slower now but holds are around 1 bar. I'll check the connections at the rear and give it a blast. Not sure if I'll get a chance tomorrow cos I'm going away with the wife for a few days, but if the weathers ok Friday/Saturday were good to go. If I had a fuel pressure issue could this be the cause of the car bogging at 0.3 bar. My peak pressure 3.7 bar of fuel pressure before it boggs. Quote Link to comment Share on other sites More sharing options...
mellonman Posted June 6, 2012 Share Posted June 6, 2012 my fpr drops very quickly to 0 too after engine is off, car does not have any problems and holds prerasure when running so didnt think i had a problem but now you got me thinking. Quote Link to comment Share on other sites More sharing options...
hodge Posted June 6, 2012 Author Share Posted June 6, 2012 my fpr drops very quickly to 0 too after engine is off, car does not have any problems and holds prerasure when running so didnt think i had a problem but now you got me thinking. What sort of fuel system do you have, do you have a check valve in place? Quote Link to comment Share on other sites More sharing options...
mellonman Posted June 6, 2012 Share Posted June 6, 2012 What sort of fuel system do you have, do you have a check valve in place? dont think so, i just have a dampener bypass,fpr and a 255 pump thats it, to be fair im not sure how they are ment to act Quote Link to comment Share on other sites More sharing options...
hodge Posted June 6, 2012 Author Share Posted June 6, 2012 dont think so, i just have a dampener bypass,fpr and a 255 pump thats it, to be fair im not sure how they are ment to act Your car won't have a check valve dude so your fuel pressure will drop straight off. Quote Link to comment Share on other sites More sharing options...
mellonman Posted June 6, 2012 Share Posted June 6, 2012 Your car won't have a check valve dude so your fuel pressure will drop straight off. thanks for clearing that up, a fpr just slows the flow back to the tank thus building pressure right? Quote Link to comment Share on other sites More sharing options...
hodge Posted June 6, 2012 Author Share Posted June 6, 2012 thanks for clearing that up, a fpr just slows the flow back to the tank thus building pressure right? That's right dude. It restricts the return to hold the pressure in the rail. It's just like a gate really that's partially open, if you know what I mean. Quote Link to comment Share on other sites More sharing options...
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