Leaning out under WOT
Apr 20, 2009, 01:34 PM
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Leaning out under WOT
Need some help here. Im leaning out under wot and fuel cutting at 5500 rpms. Ive taken it to 2 different shops to get a custom Cobb ap tune and both cant get it to stop leaning out. I took off the Xtremeboost dp thinking it would help it stop leaning out so much because of the dump tube but it actually made it alot worse.
1st and 2nd gears redline fine but 3rd and 4th gear at wot I start seeing my afr hitting in the 15s and then fuel starts cutting out at 5500 rpms! Any suggestions on how to fix this? Im thinking its the fuel pump going bad but I dont wanna keep throwing money at stuff if it doesnt fix the problems.
1st and 2nd gears redline fine but 3rd and 4th gear at wot I start seeing my afr hitting in the 15s and then fuel starts cutting out at 5500 rpms! Any suggestions on how to fix this? Im thinking its the fuel pump going bad but I dont wanna keep throwing money at stuff if it doesnt fix the problems.
Apr 20, 2009, 01:38 PM
#2
Lot's of things could be off. A tuner should be able to figure that out quickly. What is your duty cycle? Are you running out of fuel, do you need bigger injectors? How much boost are you running? Is your boost controller working properly? Do you need to increase your fuel pressure? Is your fuel pump working properly, I'd start looking there for now.
Apr 20, 2009, 01:54 PM
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Lot's of things could be off. A tuner should be able to figure that out quickly. What is your duty cycle? Are you running out of fuel, do you need bigger injectors? How much boost are you running? Is your boost controller working properly? Do you need to increase your fuel pressure? Is your fuel pump working properly, I'd start looking there for now.
Not sure what the duty cycle was. Not sure on the bigger injectors, I'm pretty sure they can handle more then 350 whp. I'm running 25 psi and tapers down to 18-19 psi. Cobb Ap sets my boost at 25 psi so I'm not running a boost controller. I'm thinking it might be the fuel pump but before I throw more money I wanted to know if anyone else has had these same problems.
Apr 20, 2009, 01:56 PM
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Considering the mod list, it looks like a stock turbo so you shouldn't need upgraded injectors/fuel pump until after 400 crank HP at least. You best bet is to check/upgrade the fuel pump as it sounds like it is doing ok off boost but then when asked to flow in the higher gears it doesn't maintain the flow or pressure. I think I read somewhere that there is a fuel pump relay that can fail that triggers low and high flow mode. You may even be able to have the local dealership check into it assuming you haven't altered anything with the fuel system yet. Also try a forum search as I think this was posted about before.
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Apr 20, 2009, 02:02 PM
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Considering the mod list, it looks like a stock turbo so you shouldn't need upgraded injectors/fuel pump until after 400 crank HP at least. You best bet is to check/upgrade the fuel pump as it sounds like it is doing ok off boost but then when asked to flow in the higher gears it doesn't maintain the flow or pressure. I think I read somewhere that there is a fuel pump relay that can fail that triggers low and high flow mode. You may even be able to have the local dealership check into it assuming you haven't altered anything with the fuel system yet. Also try a forum search as I think this was posted about before.
Apr 20, 2009, 02:05 PM
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The last time I heard of an issue such as this, someone had a bad leak in his intake. (Post MAF sensor) Basically, one of the bungs wasn't connected properly and was letting in tons of unmetered air. It's worth a quick check to make sure this isn't you problem. Any leak after the compressor isn't a concern for your problem obviously because it's under pressure instead of vacuum like the intake.
Or like the guy above me said, it's quite possible that you're running out of fuel for some reason. If you can, get a cheapo gauge and check your fuel pressure.
Or like the guy above me said, it's quite possible that you're running out of fuel for some reason. If you can, get a cheapo gauge and check your fuel pressure.
Apr 20, 2009, 02:11 PM
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The last time I heard of an issue such as this, someone had a bad leak in his intake. (Post MAF sensor) Basically, one of the bungs wasn't connected properly and was letting in tons of unmetered air. It's worth a quick check to make sure this isn't you problem. Any leak after the compressor isn't a concern for your problem obviously because it's under pressure instead of vacuum like the intake.
Or like the guy above me said, it's quite possible that you're running out of fuel for some reason. If you can, get a cheapo gauge and check your fuel pressure.
Or like the guy above me said, it's quite possible that you're running out of fuel for some reason. If you can, get a cheapo gauge and check your fuel pressure.
Apr 20, 2009, 05:06 PM
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hmmm, this is troubling me a lil bit...im going to be running a similar setup as the OP and im wondering if neone wit a similar setup are all going to run into the same problem...
Apr 20, 2009, 05:58 PM
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Sounds like the pump isn't getting the voltage it needs. It would make sense that since the car is under alot less load in 1st and 2nd that WOT would be ok and having problems in 3rd/4th. Either way, try digging and finding the thread about the poor soul who's pump lost voltage.
Apr 20, 2009, 06:17 PM
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Sounds like the pump isn't getting the voltage it needs. It would make sense that since the car is under alot less load in 1st and 2nd that WOT would be ok and having problems in 3rd/4th. Either way, try digging and finding the thread about the poor soul who's pump lost voltage.
Last edited by turizmo01; Apr 20, 2009 at 09:32 PM.