Magnum380Z Posted May 28, 2005 Share Posted May 28, 2005 Hello all, i have a 81zxt. that when i start it idles low and the oilpressure is low (according to the gauge anyway ) the car is all original and does not use oil and has less than 100k, I searched for vacuum leaks but i did not find any i asked the prvious owner about the oil pressure being low along with idle he does not know..when you are sitting at a stop light it feels like it wants to die so i have to feather the gas peddle when you take off its slow to pick up in speed.but you back off the throttle it pulls like a freight train, I do notwant to throw a lot of money into things that do not work.thanks in advance Quote Link to comment Share on other sites More sharing options...
datsunlover Posted May 28, 2005 Share Posted May 28, 2005 Could be your tps needs adjustmant/replacing... if it's on the fritz or worn, it'll 'confuse' the ECU and cause problems.. Also check all wiring conections in the engine bay, and the rubber boots and hoses for the AFM to to throttle body, turbo, ect. (cracks/leaks will cause major problems) Might wana get a manual so you can run the checks on the AFM as well.. Hope this helps. Quote Link to comment Share on other sites More sharing options...
VinhZXT Posted July 19, 2005 Share Posted July 19, 2005 Magnum, Your VCM (Vacuum Controll Module) is bad and it can't control your AAC valve. The AAC valve is what controls your idle. Just use the small screw underneath the TB to increase your throttle a bit. The oil pressure suppose to be low when you are idle. It should increase to about the middle of the gauge when you drive the car. Good luck Quote Link to comment Share on other sites More sharing options...
burnedbigas Posted July 20, 2005 Share Posted July 20, 2005 Magnum, I was wondering if you have resolved your current low idle problem. I do have the same problem on my 81 turbo motor and have been looking for any vacuum leak but havent really found any but considering my bad mileage(15-17 mpg on stock boost), i assumed I have a leak. Vinh, A friend of mine also suggested the same adjustment but have been procrastinating as schedule permits me from fixing the Z. Appreciate your help guys Quote Link to comment Share on other sites More sharing options...
VinhZXT Posted July 20, 2005 Share Posted July 20, 2005 Burn, I am running 12 PSI on my stock turbo ZXT and I get about the same gas milage as you. If you really want to get good gas milage you have to put in new injectors and replace all the sensors that controls the emission. I had the idle problem with my ZXT also and I tried to fix the VCM and AAC valves and it still not working. I guess the computer is not sending out the signals to control the VCM any more. So I removed all that stuffs and used the small screw under the TB and increase my idle a bit. Currently I am still not completely trouble free. When the car kicks into open loop mode the idle drops a little and I have to keep the idle higher for it not to stall. After it warms up the idle is perfect. My blue ZXT doesn't even kick into open loop at all so the idle doesn't drop. I don't know what your ECU will do but hope you find a good point to set the idle. Good luck Vinh Quote Link to comment Share on other sites More sharing options...
burnedbigas Posted July 21, 2005 Share Posted July 21, 2005 Will definitely try to fiddle with the screw under the TB and hope for the better. thanks! Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted July 22, 2005 Share Posted July 22, 2005 clean the throttle blade and throttle body insides.i never ran the aac valve on my car-it would idle about 1000 rpm but with a/c that was a good speed.now its got megasquirt. Quote Link to comment Share on other sites More sharing options...
burnedbigas Posted July 22, 2005 Share Posted July 22, 2005 I just drove the car tonight to take a friend for a spin. Initial problem was it would idle low and feels like it wants to stall during idle even when the car is hot(180 degrees). Haven't adjusted anything or replaced anything prior to this test run. Anyway, I basically ran the car hard from dead stop from 1st gear to 4th couple of times to show my friend what my car is all about, I have never ran my car so hard and oddly, it's boosting 8-9lbs but never really adjusted the boost since I dont have a boost controller yet(only 3" mandrel bend exhaust). So parking the car and letting it idle for a minute for a cool down, I noticed that the car is idling PERFECTLY at 20Hg on Vacuum(it was 9-10 before). So I waited for a minute and it just idled perfectly. I am excited. I'm thinking it was my injectors that was causing the poor idle and they cleared up when I drove the car really hard? Or the throttle blade/body? Any ideas and thoughts about this 'revelation'? Quote Link to comment Share on other sites More sharing options...
Magnum380Z Posted August 1, 2005 Author Share Posted August 1, 2005 I have not been driving the car lately but i ve been driving my 82 na zx it has an exhaust leak at the intake/exhaust manifold i have a gasket what is the easiest way to go about replacing it?? Also im going to get in to the Turbo car with all of everyones suggestions.. Thank you all very much I hope something works Quote Link to comment Share on other sites More sharing options...
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