STS fuel problem
07-28-2011, 07:44 PM
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STS fuel problem hey guys, its been a while, but i have yet another problem with car lol.
Car: 98' Z28 M6
Mods: Engine bone stock 94k miles with the excemption of some Comp chromoly push rods
STS turbo set up
10-13 PSI spring in wastegate, under boost it hold about 10.5
original STS Garrett turbo
walboro in-line fuel pump along with factory in-tank
48# injectors
so heres what going on, just recently started doing this, i just upped the boost to the spring listed above, and everything was peachy for about the first 2-3 weeks, but as of late when the wastegate starts to open i can watch my air/fuel gage start to back out into the stoich area, and it no longer burries its self as deep into the rich area as is used to, 1st gear still pulls hard but 2nd-4th just feels like ur cruisin down the hwy.
what could be the possible problem here? idk what my air/fuel ratios are right now as i do not have a wide band, any input would be great before i go and spend the money on a brand new in-tank and ditch the in-line and have it not be the souce of the problem.
plus the turno now puts out a decient amount of smoke, all this happened together, is the smoke a sign my oil seals r shot or could it something more serious?
any help you guys could offer would be great. Thanks
Car: 98' Z28 M6
Mods: Engine bone stock 94k miles with the excemption of some Comp chromoly push rods
STS turbo set up
10-13 PSI spring in wastegate, under boost it hold about 10.5
original STS Garrett turbo
walboro in-line fuel pump along with factory in-tank
48# injectors
so heres what going on, just recently started doing this, i just upped the boost to the spring listed above, and everything was peachy for about the first 2-3 weeks, but as of late when the wastegate starts to open i can watch my air/fuel gage start to back out into the stoich area, and it no longer burries its self as deep into the rich area as is used to, 1st gear still pulls hard but 2nd-4th just feels like ur cruisin down the hwy.
what could be the possible problem here? idk what my air/fuel ratios are right now as i do not have a wide band, any input would be great before i go and spend the money on a brand new in-tank and ditch the in-line and have it not be the souce of the problem.plus the turno now puts out a decient amount of smoke, all this happened together, is the smoke a sign my oil seals r shot or could it something more serious?
any help you guys could offer would be great. Thanks
07-29-2011, 01:28 AM
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lower the boost back down until you can get a wideband.
if it isnt tuned for that much boost that'll explain why its running lean, also you could be maxing out your current fuel setup and losing pressure.
if it isnt tuned for that much boost that'll explain why its running lean, also you could be maxing out your current fuel setup and losing pressure.
07-29-2011, 06:36 PM
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07-30-2011, 11:51 AM
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you've more then likely maxed out your fuel pump setup. If you put a fuel pressure gauge on the car, you'll more then likely see it decline as you get up there in boost. It's time to switch to twin in-tank walbros.
07-30-2011, 06:08 PM
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If your rings or a ringland is shot there are means to test that (leak down test for example)...but i'd focus on the rear driver piston (#7).
Otherwise you do seem to have fuel regulatory issues.
Otherwise you do seem to have fuel regulatory issues.