herbiemercman Posted October 14, 2015 Share Posted October 14, 2015 Hi Everyone, I ask this question as i realise that running lean can cause expensive piston failures, so apart from the engine starting to run rough and it starts knocking, then what other symptoms, if any, are there ? Also if the engine has been professionally mapped the ECU software should not change, so the causes must be down to, low octane fuel, a faulty fuel pump, worn out injectors, or a partially blocked fuel filter. ? Can you think of anything else. ? Quote Link to comment Share on other sites More sharing options...
Scott Posted October 14, 2015 Share Posted October 14, 2015 Unfortunately there's not a lot that will show a lean condition, other than a gauge. When into the realms of BPU and onward, it's best to get yourself an AFR gauge IMO. Especially when you're into hybrid turbo's where the airflow can be more efficient. Your car will run hot, EGTs will show this but again a gauge will be required. Quote Link to comment Share on other sites More sharing options...
herbiemercman Posted October 15, 2015 Author Share Posted October 15, 2015 (edited) Hi Scott, This is the reply i got from my NA/T man when i asked the question about gauges required, i just settled for the boost and oil temp gauges due to his comments below: I can ask him how probable is it for the air flow to fuel mixture to go off ? especially if the car is mapped and locked in the correct setting with the ECU ? also what is the actual exhaust maximum temperature which has not to be exceeded ? Do most owners have a exh temp gauge ? or is this just the ones which race their cars, my NA/T man as you can see thinks i do not need to be bothered with this. I always go with his reccomendations but it is good to get other opinions and experiences. My NA/T's Comments Pre the Conversion: hi buddy. the ecu has a fcd built in a boost gauge is nice to have but not essential a afr again is good to have but not a must. the mapper will have a boost gauge band afr monitor to map the car after this you should not attempt to adjust the values set. any gauges are purely for monitering purposes only. Edited October 15, 2015 by herbiemercman (see edit history) Quote Link to comment Share on other sites More sharing options...
Scott Posted October 15, 2015 Share Posted October 15, 2015 I wouldn't be without a boost gauge, an EGT gauge and an AFR gauge. Boost gauge allows you to monitor for any spikes or changes in the transition time, etc. Without it, it's hard to diagnose boost issues. EGT gauge allows you to monitor the exhaust gas temp. As long as the sensor is in a decent area (runner 6 is best) you can monitor for unsafe temps that can be caused by restrictions etc. Maximum safe limit is seen as 950DegC but you shouldn't be anywhere near that most of the time. AFR gauge allows you to monitor the air/fuel mixture in the car. Stock ECU cars tend to run really rich but again it's great for making sure everything is in check. Given your current situation if you had all 3 gauges you would have been able to give us so much more information to diagnose your issue. You had a fuelling issue, if you had the AFR & EGT gauge you would be able to tell us that the EGTs were high and the AFR was far too lean. You would also be able to tell us what boost this was happening at and whether or not it was overboosting. When everything is working great these gauges are useless. The same can be said for the water temperature though, which is stock in almost every car made. Solid investments IMO. If you get these gauges and fit them, you will get to know how your car runs during certain operations and if there's any change, you'll notice it straight away. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted October 15, 2015 Share Posted October 15, 2015 I always go the belt and braces approach...so all relevant gauges, however having said that its really down to how much you trust your mapper. Other than that things can and do go out, or fail, but its usually a rarity, air leaks during vacuum will cause a lean mixture, but an air leak during boost after the airflow has been metered, will normally cause a rich mixture, the other ways to go lean are fuel system restriction, IE bad pump, blocked fuel filter, bad injector, then you have over boost, and failed MAP or MAF. But as already said you very unlikely to know unless you have the relevant gauges fitted, of course you may notice knock/pre ignition if you have a good ear, and you can sometimes get a mild misfire or a slight drop in power, but most will not notice, combustion temps will also rise but your average coolant temp gauge will not reflect this. Quote Link to comment Share on other sites More sharing options...
bignum Posted October 15, 2015 Share Posted October 15, 2015 Thats why i love my syvecs, i can just enjoy thrashing the car round a track all day without trying to listen for noises and worry about stuff, if the ecu doesn`t pick up a problem then ive got no chance. Quote Link to comment Share on other sites More sharing options...
herbiemercman Posted October 15, 2015 Author Share Posted October 15, 2015 Hi Guys, More info and well grateful for it, i am an engineer and inherently a "belt and brasses" person, i have a tuna fishing boat in Stranraer marina, it is 40 ft long and i have had it 32 years, and i have lots of kit which are for "Back up", spare fuel tanks, switch over batteries, floatation suits, all required when we steam to the Isle of Man for the anual TT races. I just have to relax a bit and see where my NA/T man sends me ?, as i stated earlier, i have 100% trust in his experience and knowledge, this does not mean i am any less appreciative for people like scott, tricky, chris and bignum, this is a great club. I am grateful to you all. herbiemercman. Quote Link to comment Share on other sites More sharing options...
Style Posted October 16, 2015 Share Posted October 16, 2015 The good thing us NA guys have going for us is that the engines are relatively cheap to replace. I've seen them given away for free on here before! But generally a couple hundred bucks and a small wedge of labour to the right garage will see you back on the road again. I've got the bells and whisltes approach on my NA-T with Oil Press. Oil Temp, Fuel Press, AFR and Boost with alarms set if they drop off their thresholds. It sure fills the cockpit a bit but I don't think I could go without seeing them to be honest. http://mkivsupra.net/vbb/attachment.php?attachmentid=189500&stc=1&d=1407506337 Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted October 16, 2015 Share Posted October 16, 2015 I thought that was a pic of Blackpool illuminations at first glance Quote Link to comment Share on other sites More sharing options...
Style Posted October 16, 2015 Share Posted October 16, 2015 AFR gauge wasn't even on at this stage, it's quite the spectacle Quote Link to comment Share on other sites More sharing options...
Nodalmighty Posted October 16, 2015 Share Posted October 16, 2015 I thought that was a pic of Blackpool illuminations at first glance My thoughts too. How do you see where you are going ? Quote Link to comment Share on other sites More sharing options...
Style Posted October 16, 2015 Share Posted October 16, 2015 I had the dimmer up at full, turn them down they're not so bad It's a Heckler LED conversion so they are hella bright on full setting as you can see Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted October 16, 2015 Share Posted October 16, 2015 Fit a proper wide band Lambda readout, then you can peer at that whilst running into a ditch. You seem to be worrying about a lot about things, just Google weak mixture. But basically very lean on a turbo engine will give remarkable fuel economy, high EGT's and combustion temps, high oil temps, possibly raised water temps, and in severe cases cause pinging or even detonation. Detonation can do immense damage in less than 5 seconds. You need a wide band, right up near the turbo, to read mixture. Plug and exhaust tail pipe colour are pretty much totally irrelevant with modern additive laden unleaded fuels. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted October 16, 2015 Share Posted October 16, 2015 My thoughts too. How do you see where you are going ? I don't think he does, look where he's ended up.... Quote Link to comment Share on other sites More sharing options...
Style Posted October 16, 2015 Share Posted October 16, 2015 I'm down in the Peak District next week Chris (against my will of course ) so keep your eyes on the horizon and you'll probably see the 'illuminations' Quote Link to comment Share on other sites More sharing options...
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