tyson Posted June 18, 2002 Share Posted June 18, 2002 I have an 81 ZXT with an automatic transmission. Stock boost levels, all new injectors/plugs/wires, exhaust has muffler removed. Runs GREAT, except. My autometer lean/rich gauge is telling me I am running mid-rich at full power. Not way rich, and not lean. When I gun it, I have OK power under 4,000 RPMs, but the instant I hit 4,000 RPMS it is like someone turned on the "more power switch". It is a pretty big change in power. Here is the kicker, I reach full boost of 7.5 psi at around 3,000 RPMs in first gear, so I know it isnt lag. I do notice it in second gear also. Not quite sure about third, it is hard to notice, and I havent had much of a chance to play with it yet. I noticed this kindof after I cut off my muffler, but I am not sure if it was that, or if it happened before or after. I am just noticing it. Could this be an automatic transmission problem, like that it isnt grabbing very well? I have done a couple burnouts and brakestand launches, I have no idea how an automatic works. Any help? Thanks Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted June 18, 2002 Share Posted June 18, 2002 I know the bump you are talking about, I experienced it with my 240z turbo engine. I think it is an inherant problem with the efi set-up. I have talked to Clark at JWT about it, and there is not much you can do about it. Raising your boost will lower the rpm where this bump occurs. I can't remember the terminology used to describe what happens, but it sucks, and it is hardwired into the system. It is fuel related too. Kind of like the injectors will only do 45% duty cycle and then all at once they shift to 90%, or what ever the setting is. I don't have that problem with my JWT set-up, and any aftermarket EFI won't have it either. You may be able to do some tweeking with your set-up like reclocking the AFM, but some of the tinkering experts will have to help you with that. I would think loosening the spring a little would help. Quote Link to comment Share on other sites More sharing options...
turbobluestreak Posted October 31, 2002 Share Posted October 31, 2002 I had this problem in my zxt when I installed the z31 ecu and it turned out to be the Crank Angle Sensor you might want to look at it. tbs Quote Link to comment Share on other sites More sharing options...
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