abtin90 Posted May 14, 2013 Share Posted May 14, 2013 My NA-T has gone in for mapping but its leaning out ridiculously at 5000rpm. The car has gone through various stages and it continues to horribly lean out after 5k getting leaner and leaner as it approaches redline. The car is running lower compression with a boostlogic headgasket, and I'm using an AEM standalone. Any advise will he much appreciated as the garage have run out of ideas. Thanks in advance Quote Link to comment Share on other sites More sharing options...
abtin90 Posted May 14, 2013 Author Share Posted May 14, 2013 Also I can post more of the cars spec if it helps? Quote Link to comment Share on other sites More sharing options...
Wez Posted May 14, 2013 Share Posted May 14, 2013 What's the injector duty? Quote Link to comment Share on other sites More sharing options...
abtin90 Posted May 14, 2013 Author Share Posted May 14, 2013 What's the injector duty? I'll have to check with the mapper in the morning. It's running precision 550 injectors. Quote Link to comment Share on other sites More sharing options...
Marco79 Posted May 14, 2013 Share Posted May 14, 2013 I'll have to check with the mapper in the morning. It's running precision 550 injectors. What bhp you running and what fuel pump do you have mate? Quote Link to comment Share on other sites More sharing options...
abtin90 Posted May 14, 2013 Author Share Posted May 14, 2013 What bhp you running and what fuel pump do you have mate? Not too sure on the latest bhp result. When they first started mapping they called and said it had made around 370 at 0.6 bar (I think). Can check in the morning if needed. Was aiming for as close to 500 as possible. And it's got a walbro 255 fuel pump. Quote Link to comment Share on other sites More sharing options...
johnny g Posted May 14, 2013 Share Posted May 14, 2013 Does it have an adjustable fuel pressure regulator? Quote Link to comment Share on other sites More sharing options...
abtin90 Posted May 14, 2013 Author Share Posted May 14, 2013 Does it have an adjustable fuel pressure regulator? It does now. It didn't at first but fitted one thinking it would solve the issue but it hasn't Quote Link to comment Share on other sites More sharing options...
johnny g Posted May 14, 2013 Share Posted May 14, 2013 I'm guessing that it's either injector duty or the fuel lines/rail might be too small. Your pump is good for around 480-500 IIRC Quote Link to comment Share on other sites More sharing options...
abtin90 Posted May 14, 2013 Author Share Posted May 14, 2013 I'm guessing that it's either injector duty or the fuel lines/rail might be too small. Your pump is good for around 480-500 IIRC Cheers for the input. Any idea on what size fuel lines would be needed to run that sort of power? Quote Link to comment Share on other sites More sharing options...
Marco79 Posted May 14, 2013 Share Posted May 14, 2013 Are you still using the stock fuel pump ecu? If you are that might be faulty and not switching the pump from 9v to 12v giving you a lean mix? Quote Link to comment Share on other sites More sharing options...
abtin90 Posted May 14, 2013 Author Share Posted May 14, 2013 Are you still using the stock fuel pump ecu? If you are that might be faulty and not switching the pump from 9v to 12v giving you a lean mix? The garage had told me that they had done a fuel pump ecu bypass. Not exactly sure on how they achieved it and what effect it would have. Though they did say that the pump was running at 12v now Quote Link to comment Share on other sites More sharing options...
Noz Posted May 15, 2013 Share Posted May 15, 2013 The ECU bypass will give the pump less power when the pump is not required in the lower rpm range. It won't really affect the running of the car. They would of just used a relay to activate the fuel pump which would just switch to 12v and not have a 9v/12v variation. I know it's a ball ache, but is it worth looking at the spark plugs. It may show one cylinder is running lean instead of the whole tune. Perhaps the problem is with one cylinder only and not the map/setup you have. Maybe even a dodgy injector. Did you use resistors with the injectors, if so were they the correct value? Quote Link to comment Share on other sites More sharing options...
Ian C Posted May 15, 2013 Share Posted May 15, 2013 Whats the static fuel pressure, what duty cycle are you seeing when it goes lean, and how much boost is it running at this time? All that should help narrow this down quite quickly Quote Link to comment Share on other sites More sharing options...
abtin90 Posted May 15, 2013 Author Share Posted May 15, 2013 The ECU bypass will give the pump less power when the pump is not required in the lower rpm range. It won't really affect the running of the car. They would of just used a relay to activate the fuel pump which would just switch to 12v and not have a 9v/12v variation. I know it's a ball ache, but is it worth looking at the spark plugs. It may show one cylinder is running lean instead of the whole tune. Perhaps the problem is with one cylinder only and not the map/setup you have. Maybe even a dodgy injector. Did you use resistors with the injectors, if so were they the correct value? They said they've checked the plugs numerous times but couldn't find a fault. I just called them now and they said they've used resistors and they're the correct size. They've also tried swapping over the injectors to a different set and they're still having the same problem. Quote Link to comment Share on other sites More sharing options...
abtin90 Posted May 15, 2013 Author Share Posted May 15, 2013 Whats the static fuel pressure, what duty cycle are you seeing when it goes lean, and how much boost is it running at this time? All that should help narrow this down quite quickly Thanks for the reply. I just gave them a call and they said the following. They said that the static fuel pressure is around 3 bar and that active is 5 bar on boost. The cycle duty is around 50% when it goes lean. And that its only running 0.6 bar when going lean at 5000rpm. They said they've checked the fuel likes and that they all seem good. Quote Link to comment Share on other sites More sharing options...
Noz Posted May 15, 2013 Share Posted May 15, 2013 if injector cycle is at 50% can't they increase the fueling Quote Link to comment Share on other sites More sharing options...
Wez Posted May 15, 2013 Share Posted May 15, 2013 What fuel pressure reg are you running? Quote Link to comment Share on other sites More sharing options...
abtin90 Posted May 15, 2013 Author Share Posted May 15, 2013 if injector cycle is at 50% can't they increase the fueling Doubt if would be that simple to be honest as surely they would have done that lol. But I'll mention it. Quote Link to comment Share on other sites More sharing options...
abtin90 Posted May 15, 2013 Author Share Posted May 15, 2013 What fuel pressure reg are you running? It's a sard fuel pressure regulator. Was brand new too. Quote Link to comment Share on other sites More sharing options...
Ian C Posted May 15, 2013 Share Posted May 15, 2013 If they really are seeing 50% duty cycle and it's going lean, then the obvious explanation is "increase the injector duty, duh". If what's really happening is "we've upped it to 50% already from say 35% and it's still just as lean" then that means not enough fuel is being delivered to the injectors. However I'd expect fuel pressure to significantly drop off as the pump couldn't maintain the pressure. So from what's been said so far, increase the duty cycle Could also be a weak pump or restriction in the fuel system pre-injectors, but again you'd need to see a big dropoff in fuel pressure for it to be that. Quote Link to comment Share on other sites More sharing options...
abtin90 Posted May 15, 2013 Author Share Posted May 15, 2013 If they really are seeing 50% duty cycle and it's going lean, then the obvious explanation is "increase the injector duty, duh". If what's really happening is "we've upped it to 50% already from say 35% and it's still just as lean" then that means not enough fuel is being delivered to the injectors. However I'd expect fuel pressure to significantly drop off as the pump couldn't maintain the pressure. So from what's been said so far, increase the duty cycle Could also be a weak pump or restriction in the fuel system pre-injectors, but again you'd need to see a big dropoff in fuel pressure for it to be that. Thanks for the reply again. I'll call them in morning again and let them know what you and other members have suggested. I'll update this as soon as I hear back. If anyone else has any other suggestions please let me know. Quote Link to comment Share on other sites More sharing options...
abtin90 Posted May 15, 2013 Author Share Posted May 15, 2013 If they really are seeing 50% duty cycle and it's going lean, then the obvious explanation is "increase the injector duty, duh". If what's really happening is "we've upped it to 50% already from say 35% and it's still just as lean" then that means not enough fuel is being delivered to the injectors. However I'd expect fuel pressure to significantly drop off as the pump couldn't maintain the pressure. So from what's been said so far, increase the duty cycle Could also be a weak pump or restriction in the fuel system pre-injectors, but again you'd need to see a big dropoff in fuel pressure for it to be that. So I just got off the phone with them. Apparently they were still at the garage working late trying to find the fault. They said they had already upped the cycle duty from 50% but the same thing happens and the fuel leans out ridiculously at 5200rpm. They've also tried swapping the pump for another walbro 255, they've checked the injectors and lines and the same problem keeps occurring. They said they did notice that for some strange reason the speedo was moving with the revs which they said they'd be looking into. Quote Link to comment Share on other sites More sharing options...
Ian C Posted May 15, 2013 Share Posted May 15, 2013 Does the fuel pressure drop off when it leans out? Might still be one dodgy injector out of the bunch. Sounds also like it might be an electrical issue of some sort. Can they scope the actual duty cycle/duration at an injector, as what the ECU says it's doing may not really be what the injector is being told to do. Quote Link to comment Share on other sites More sharing options...
abtin90 Posted May 15, 2013 Author Share Posted May 15, 2013 Does the fuel pressure drop off when it leans out? Might still be one dodgy injector out of the bunch. Sounds also like it might be an electrical issue of some sort. Can they scope the actual duty cycle/duration at an injector, as what the ECU says it's doing may not really be what the injector is being told to do. Yeah the fuel drops off. I was just speaker to them again and they're saying the injectors they fitted are low impedance and there's no resistor pack. However they're saying the AEM allows you to select whether the injectors are high or low impedance. Could the fact that the car has low impedance injectors without a resistor pack be the issue? Quote Link to comment Share on other sites More sharing options...
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