300zx tt smokes on deceleration
03-16-2008, 12:22 PM
#1
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300zx tt smokes on deceleration
I have a 1990 tt that I just replaced the turbo's on . They were new according to the person I purchased them from. Car didn't smoke before I replaced them, but I did have a bad turbo. Car boost is about 8 psi now ,it was about 14 psi before bad turbo. Car idles fine with no smoke. Just smokes on deceleration.I did take the EGR system off, Not sure what I have done wrong . smokes from both sides.
new oem turbos
new oem turbos
03-16-2008, 07:09 PM
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Originally Posted by snwbrderphat540
what color smoke? and why 8 psi now compared to the 14 might just be rich
oh and what upgrades did you do to the car?
oh and what upgrades did you do to the car?
Upgrades are. Basic JWT chip, under drive pulley, down pipe, no cat, after market mid pipe and exhaust, not sure what brand they are, came with the car, Godspeed radiator and electric fan. I put the new turbos on because I had one that was whining . While the motor was out I pulled the intake off to put on value cover gaskets, I also pull the egr system off at the same time. Car ran great before I lost the passenger side turbo. Thanks for the help
03-16-2008, 07:13 PM
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Originally Posted by willkrom1990
arn't they known to let out a bit of steam after that job? but definately, the color of the smoke will help a lot
03-16-2008, 07:17 PM
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Originally Posted by ZLover4Life
What changes did you make that resulted in the change in boost?
03-16-2008, 07:24 PM
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Originally Posted by craftm
Hi thanks for looking. The smoke is "white" smell like oil not sure.
Upgrades are. Basic JWT chip, under drive pulley, down pipe, no cat, after market mid pipe and exhaust, not sure what brand they are, came with the car, Godspeed radiator and electric fan. I put the new turbos on because I had one that was whining . While the motor was out I pulled the intake off to put on value cover gaskets, I also pull the egr system off at the same time. Car ran great before I lost the passenger side turbo. Thanks for the help
Upgrades are. Basic JWT chip, under drive pulley, down pipe, no cat, after market mid pipe and exhaust, not sure what brand they are, came with the car, Godspeed radiator and electric fan. I put the new turbos on because I had one that was whining . While the motor was out I pulled the intake off to put on value cover gaskets, I also pull the egr system off at the same time. Car ran great before I lost the passenger side turbo. Thanks for the help
03-16-2008, 08:50 PM
#12
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exactly my words from zlover
however makes me wonder with the re-flashed ECU if it was done for the purpose of the 14 psi and now your running only 8 would cause a richer state and could cause more smoking, but it does burn black, under acceleration at least, when you coast down however could be different and its just burning off a little un spent fuel. however at idl once off the throttle it wouldnt continue to run rich. i doubt its anything unless its a pretty large amount of smoke but do a compression test. also, the turbos are liquid cooled so id imagine tis possible for them to leak into the exhaust turbine. but these were new right? so very unlikely. out of curiousity where did you get them?
and also whats the tempurature outside where your located
however makes me wonder with the re-flashed ECU if it was done for the purpose of the 14 psi and now your running only 8 would cause a richer state and could cause more smoking, but it does burn black, under acceleration at least, when you coast down however could be different and its just burning off a little un spent fuel. however at idl once off the throttle it wouldnt continue to run rich. i doubt its anything unless its a pretty large amount of smoke but do a compression test. also, the turbos are liquid cooled so id imagine tis possible for them to leak into the exhaust turbine. but these were new right? so very unlikely. out of curiousity where did you get them?
and also whats the tempurature outside where your located
03-16-2008, 09:05 PM
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Eric, it cannot be running rich because of an ECU that is "set for 14psi." That's not how ECU's work, they work off air flow readings from the MAS. Aftermarket ECU's are programmed to run more rich than stock so that they can handle the extra air and heat from additional boost pressures, but they are absolutely not programmed for a specific boost level. So if his MAS is showing that the turbos are drawing in airflow conducive to 8psi of boost, it's going to dump the fuel needed for 8psi of boost. If his turbos are sucking in 14psi, it will dump enough fuel for 14psi. As we both said though, it'd burn black if it were a rich condition.
I run 17-18psi on my engine, but I could easily back down to the 12psi wastegate preset and my car would not dump unnecessary fuel.
Yes, the turbos could leak coolant and thus burn white, but that's harder to test than the compression so we'll tackle that if compression comes back fine.
willkrom1990 - If he were to swap an oil and coolant line on the turbo (which I don't think it possible because the bolt threading and sizing is different IIRC, in addition to the feeds being hardlines and thus only lining up with the right connections), there'd be MUCH larger issues than a little bit of white smoke on deceleration. When has this ever happened before? Because I've never heard of it on a Z32. He'd have oil in his coolant and coolant in his oil... neither would necessarily cause white smoke out of the exhaust and both of which would cause major issues in the engine itself (coolant is not a good lubricant and oil is not good for heat exchange).
Thus, I highly doubt he has a coolant and oil line mixed up on his turbos... you'd have to purposely mix them up for that to happen.
I run 17-18psi on my engine, but I could easily back down to the 12psi wastegate preset and my car would not dump unnecessary fuel.
Yes, the turbos could leak coolant and thus burn white, but that's harder to test than the compression so we'll tackle that if compression comes back fine.
willkrom1990 - If he were to swap an oil and coolant line on the turbo (which I don't think it possible because the bolt threading and sizing is different IIRC, in addition to the feeds being hardlines and thus only lining up with the right connections), there'd be MUCH larger issues than a little bit of white smoke on deceleration. When has this ever happened before? Because I've never heard of it on a Z32. He'd have oil in his coolant and coolant in his oil... neither would necessarily cause white smoke out of the exhaust and both of which would cause major issues in the engine itself (coolant is not a good lubricant and oil is not good for heat exchange).
Thus, I highly doubt he has a coolant and oil line mixed up on his turbos... you'd have to purposely mix them up for that to happen.
03-16-2008, 09:31 PM
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your right randy, ive been hanging out with these old cars to much 
damn S30's use AFM's so it all is preset even on the turbo S130's because if the AFM is fully opened, its fully opened it cant tell the velocity of air thats keeping the flapper open.
damn S30's use AFM's so it all is preset even on the turbo S130's because if the AFM is fully opened, its fully opened it cant tell the velocity of air thats keeping the flapper open.
03-17-2008, 09:01 PM
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[QUOTE=ZLover4Life]Eric, it cannot be running rich because of an ECU that is "set for 14psi." That's not how ECU's work, they work off air flow readings from the MAS. Aftermarket ECU's are programmed to run more rich than stock so that they can handle the extra air and heat from additional boost pressures, but they are absolutely not programmed for a specific boost level. So if his MAS is showing that the turbos are drawing in airflow conducive to 8psi of boost, it's going to dump the fuel needed for 8psi of boost. If his turbos are sucking in 14psi, it will dump enough fuel for 14psi. As we both said though, it'd burn black if it were a rich condition.
I run 17-18psi on my engine, but I could easily back down to the 12psi wastegate preset and my car would not dump unnecessary fuel.
Yes, the turbos could leak coolant and thus burn white, but that's harder to test than the compression so we'll tackle that if compression comes back fine.
willkrom1990 - If he were to swap an oil and coolant line on the turbo (which I don't think it possible because the bolt threading and sizing is different IIRC, in addition to the feeds being hardlines and thus only lining up with the right connections), there'd be MUCH larger issues than a little bit of white smoke on deceleration. When has this ever happened before? Because I've never heard of it on a Z32. He'd have oil in his coolant and coolant in his oil... neither would necessarily cause white smoke out of the exhaust and both of which would cause major issues in the engine itself (coolant is not a good lubricant and oil is not good for heat exchange).
Thus, I highly doubt he has a coolant and oil line mixed up on his turbos... you'd have to purposely mix them up for that to happen.[/QUOTE
I did a compression test today.The driver side is 115 psi on each one and the passenger side is 120 psi on each one. I drove the car longer today and the smoke color is blue sorry to mislead everyone. Thanks
I run 17-18psi on my engine, but I could easily back down to the 12psi wastegate preset and my car would not dump unnecessary fuel.
Yes, the turbos could leak coolant and thus burn white, but that's harder to test than the compression so we'll tackle that if compression comes back fine.
willkrom1990 - If he were to swap an oil and coolant line on the turbo (which I don't think it possible because the bolt threading and sizing is different IIRC, in addition to the feeds being hardlines and thus only lining up with the right connections), there'd be MUCH larger issues than a little bit of white smoke on deceleration. When has this ever happened before? Because I've never heard of it on a Z32. He'd have oil in his coolant and coolant in his oil... neither would necessarily cause white smoke out of the exhaust and both of which would cause major issues in the engine itself (coolant is not a good lubricant and oil is not good for heat exchange).
Thus, I highly doubt he has a coolant and oil line mixed up on his turbos... you'd have to purposely mix them up for that to happen.[/QUOTE
I did a compression test today.The driver side is 115 psi on each one and the passenger side is 120 psi on each one. I drove the car longer today and the smoke color is blue sorry to mislead everyone. Thanks
03-17-2008, 09:56 PM
#20
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Yep... that's low compression and burning oil. I consider 120 to be the lowest acceptable compression. But I don't think the worn rings (which are likely the cause of your poor compression) are the cause of your smoking.
I should've thought about this before, in the case that the smoke really was blue, but I think you need to do a leakdown test (sorry to make you do essentially another compression test). A leakdown test (if you don't know) is simple doing a compression test and letting the gauge sit for a while while monitoring the drop in pressure over time - it's the best way to diagnose bad valves which, for your sake, I hope to be the problem.
At this point, it's most likely either leaky valves letting oil into the combustion chamber or bad turbos, IMO.
Sorry if I don't feel like scanning through your posts right now (I'm busy), but when was the last time the headgasket was replaced? I'd recommend replacing it if it's been a while, and doing a 3-angle valve job while the heads are off.
I should've thought about this before, in the case that the smoke really was blue, but I think you need to do a leakdown test (sorry to make you do essentially another compression test). A leakdown test (if you don't know) is simple doing a compression test and letting the gauge sit for a while while monitoring the drop in pressure over time - it's the best way to diagnose bad valves which, for your sake, I hope to be the problem.
At this point, it's most likely either leaky valves letting oil into the combustion chamber or bad turbos, IMO.
Sorry if I don't feel like scanning through your posts right now (I'm busy), but when was the last time the headgasket was replaced? I'd recommend replacing it if it's been a while, and doing a 3-angle valve job while the heads are off.
04-15-2008, 05:21 PM
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hi i have the same problem with my 300zxtt and i had rebuilt my motor i have change oem valve seal,ring,oem full gasket kit,3 angle valve job,rebuilt my head, and more . my car still smoke blue when i decelereting i have another problem my oil pressure is low and he stall. i will try to block my egr valve and my pcv valve
04-16-2008, 06:01 PM
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... because your turbos are probably shot.
Where was the oil? The PCV's vent into the plenum itself (and when they go bad, they cause the dipstick to shoot out). If the oil was anywhere before the throttle bodies, it's not from the PCV's.
Where was the oil? The PCV's vent into the plenum itself (and when they go bad, they cause the dipstick to shoot out). If the oil was anywhere before the throttle bodies, it's not from the PCV's.
