g686 Posted July 17, 2007 Share Posted July 17, 2007 My problem is when i drive the car as soon as it hits boost at 4000 rpm the car will fall on its face. The car is a 82 turbo motor with the z31 maf and ecu in it. I know this problem has been discussed before and i have done countless searches and cant find an answer that works. heres what i have done so far, I have cleaned all the connections with brake clean, i have checked the fuel pressure when i am driving and it doesn't loose pressure at all, i have bought a wide band o2 sensor and is telling me that my car is running lean on boost. NOW heres the interesting part, i diconnected my CHTS and the car ran fine an still went lean when i was driving it... like 20:1 AFR!!! I have also replaced the maf? Now i am wondering if there is something i am missing? what would cause the car to run lean all the time? the car is a 240z so it does'nt have a speed sensor, would this cause a problem like this? Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 18, 2007 Share Posted July 18, 2007 I know the ECU will swap to batch fire two injections over a certian point (I'm recalling 5000+) and if you have clogged injectors it shows up then by sinking the rings on five of six pistons and acting like the car hist a rev limiter of some sort. Don't know if this is your situation or not. Quote Link to comment Share on other sites More sharing options...
g686 Posted July 19, 2007 Author Share Posted July 19, 2007 i pulled out a few of the injectors and they looked good, they weren't clogged at all? is there some sensor the z31 ecu uses that i dont have hooked up? like a speed sensor or fuel temp sensor? Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 19, 2007 Share Posted July 19, 2007 Fuel Temp Sensor can be 'resistored' and that should do it. I think it gets tied high on the board when guys mod it. But a resistor in the connector for the sensor with the proper resistance equal to say middle range would remove that from the equation. I don't think the speed sensor does much. Quote Link to comment Share on other sites More sharing options...
lifegrddude Posted July 20, 2007 Share Posted July 20, 2007 How much boost are you running? Quote Link to comment Share on other sites More sharing options...
g686 Posted July 21, 2007 Author Share Posted July 21, 2007 im running the stock 6-7 psi Quote Link to comment Share on other sites More sharing options...
Bernardd Posted July 21, 2007 Share Posted July 21, 2007 The z31 manual states that at 3k it switches to simultaneous injection. I would guess that it's either the maf, ecu or a wiring/connection issue. Replacing the maf and ecu is straightforward, checking for continuity from sensor to ecu is a good idea as well. I recently had a connector issue with similar symptons. It was the maf connection that was bad in my case. Quote Link to comment Share on other sites More sharing options...
g686 Posted July 22, 2007 Author Share Posted July 22, 2007 ill test all of the connectors and see if they are all working properly. thanks Quote Link to comment Share on other sites More sharing options...
whitechocolatelove Posted December 25, 2008 Share Posted December 25, 2008 i have a 240z turbo swapped with stock everything and im having the same problem. did you happen to fix it? Quote Link to comment Share on other sites More sharing options...
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