cygnusx1 Posted June 21, 2004 Share Posted June 21, 2004 Can this be happening to me? With my new TO4B Hybrid turbo, I build to 14psi by about 2800rpm and it pulls hard through 3rd gear up to about 4700 rpms and then, with my foot still to the floor, the boost gauge goes to 22" vacuum!!!! and power disappears like someone turned off the key! I am using the stock rubber boot between the AFM and the Turbo but I removed the metal coil from the inside of it. I can't explain what else would cause this problem. The rest of the upstream intake tract is not collapsing because it is rigid. Once the problem occurs. I lift my foot for about 2 seconds and hammer it again and pulls hard and then repeats all over again. Also, what would cause half throttle, low boost (5psi), stutter, and black puffs of richness smoke? Once I get through the stuttering and smoke period I can go to full throttle. Boost builds and it rockets away. Stock fuel system and ignition all set to factory spec. AFM spring adjusted to get good running. Some tech details in my sig. (FMU Disconnected) Quote Link to comment Share on other sites More sharing options...
Roostmonkey Posted June 21, 2004 Share Posted June 21, 2004 Try removing the air filter. Quote Link to comment Share on other sites More sharing options...
lifegrddude Posted June 21, 2004 Share Posted June 21, 2004 Cygnusx1, you are right on target about the intake hose collapsing. When I did my turbo swap, I thought about removing the spring wire, but noticed the rubber became extremely flimsy without and put it back in. I believe your hose is squishing down when the turbo starts to pull a lot of air. John 82ZXT Quote Link to comment Share on other sites More sharing options...
Sean73 Posted June 21, 2004 Share Posted June 21, 2004 I doubt it's the intake collapsing. There is only a small amount of vacuum in the intake hose, even under high boost, not enough to collapse the hose. Your problem sounds like a faulty wastegate. Test the wastegate with compressed air and see what happens. I had this happen to me as well. Had identical symptoms as yours. I got a faulty wastegate acuator with my rebuilt t3/t04e. The half throttle richness sounds like a faulty TPS. I wouldn't rule out the AFM either. Sean 73 240Z, L28ET, T3/T04E, NPR IC, Z31 ECCS Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted June 22, 2004 Author Share Posted June 22, 2004 Update: I thought it was the wastegate as well but if the wastegate blows open, I would see 0psi at the lowest. I was seeing full vacuum with my foot buried in the floorpan. I had the duct spring laying there so I took out the hose and put the spring back in. Went for a spin and no more problem! Oh well I should never have doubted those Nissan Engineers and left the spring in there. This also indicates that my home-made cold air intake and Fram truck filter are causing restrictions. BTW Roostmonkey Thanks,It was a good idea to remove the air filter as a test. It still hesitates a bit at part throttle while boost is building and smokes a bit too at that transition but I think I need to go over all connections and test all components again. I am thinking that it is definately a mixture curve vs. boost curve issue. Quote Link to comment Share on other sites More sharing options...
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