Guest Anonymous Posted January 16, 2003 Share Posted January 16, 2003 hi there, this is my first time posting. I have a 1982 280zxTurbo with 121k miles. It is an auto and currently the only mod on it is a 3 inch downpipe back exhaust system with highflow cat and magnaflow muffler. The rest is stock For the past 7 months i have been having trouble passing smog and the car has been running rich. i have tried just about everything to diagnose and fix this problem. i have even taken it to mechanics but the people around here are dumb and all they want to do is change your spark plugs and charge you 300 dollars for it. i have replaced/checked just about everything ive heard about. i have been posting on zcar.com here are some posts http://www.zcar.com/forums/read.php?f=1&i=291234&t=291234 http://www.zcar.com/forums/read.php?f=1&i=295329&t=295329 http://www.zcar.com/forums/read.php?f=1&i=303696&t=303696 http://www.zcar.com/forums/read.php?f=1&i=301007&t=301007 http://www.zcar.com/forums/read.php?f=1&i=310633&t=310633 http://www.zcar.com/forums/read.php?f=1&i=325535&t=325535 I need to get my ZX to pass smog. It is a 82ZXT with Auto transmission. Mileage is around 121000. The car runs strong but shows rich in the smog tests. I have done just about anything i can. I have changed a lot of parts for new ones, including o2 sensor, whole exhaust system with new cat, new egr, checked my ecu, new injectors, new fpr, new aac valve, new afm, tps is okay. did a compression check and it came out okay. i have checked my valves, i have new spark plugs, whole new ignition system. The fuel lines are clear. There might be a couple other things that i have done that escapes my memory... Mechanics dont know what to do down here.. they are stupid and want to replace the parts ive already replaced. any tips or ideas on what may be wrong with my car? Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 16, 2003 Share Posted January 16, 2003 oh yeah and the gas mileage is 18mpg around town and about 22 freeway Quote Link to comment Share on other sites More sharing options...
fl327 Posted January 16, 2003 Share Posted January 16, 2003 lean out the idle in the afm? is it factory new or is it a good used unit? i would say lean it out in the afm, how bad is your car failing? i dont think its the headgasket, you have good compression readings across the board. Quote Link to comment Share on other sites More sharing options...
Clifton Posted January 17, 2003 Share Posted January 17, 2003 What's your timing set at? What gas is it failing and what are the numbers? 18 mpg city sounds pretty good. You must baby that thing . Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 17, 2003 Share Posted January 17, 2003 i dont think theres an idle screw on the 82 280zxt, unless the afm is open. this afm is closed. the car is failing REALLY bad so i dont think adjusting the afm would help, ive tried with the other open afm i have and it didnt help. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 17, 2003 Share Posted January 17, 2003 here are the results at 15mph the HC was 179.. the max is 138. gross polluter status is 328 the CO was 6.57 and the max is 0.98 with gp at 2.48 the NO was 108 max being 1227 and gp at 2253 for 25mph the hc was 174, max at 110, gp at 261. the co was 6.89, the max at 0.78 and gp at 2.28 the no was 31, max is 1087 and gp is 2053 Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted January 17, 2003 Share Posted January 17, 2003 Sure you've got the right injectors? If you were running the SVO injectors I would expect you to be this rich all the time... Quote Link to comment Share on other sites More sharing options...
Guest HIGHRPM Posted January 18, 2003 Share Posted January 18, 2003 Being that I don't know the 280 injection system I might be a little off base. All the FI cars that I've worked with over the yearshave basicaaly the same type of monitoring and metering systems. The Air mass meter measures the amount of air entering the motor and sends its readout to the ECU. Combined to this is the Throttle position sensor which tells the ECU the whereabouts of the throttle plate is in relation to its bore.Combined with that is the Temp sensor which tells the ECU how warm the motor is . These inputs are then calculated by the ECU and then the injectors are fired according to the info provided.The temp sensor is a major problem source!! If the reading is wrong going to the ECU, then the injectors will be fired either too long or to short causing richness or leanness.A shop manual would tell you what the resistance should be at a given temp, so check this out for sure. If your base timing is out, your injection pulses will be mistimed, again causing problems. If there is an air leak in the intake system "after" the Air mass meter, then the 02 sensor is reading a greater amount of oxygen and therefor the ECU will again richen the mixture. Excessive fuel pressure can also cause a rich mode, so pressure should be checked. ECU failure is RARE, as compared to the Input Sensors that it uses.A recap would be: 1. check timing 2. check fuel pressure 3. check resistance values of Temp sensor 4. check for air leaks after Air mass meter 5. check operation of Throttle position switch 6. check to see if the injectors are leaking by Hope this helps a bit. Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted January 18, 2003 Share Posted January 18, 2003 I'm not familiar either. But, does the L28E use a Idle Air control solinoid, or other such device? If it was malfunctioning(stuck, dirty, etc...), It would cause similar symtoms. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 21, 2003 Share Posted January 21, 2003 AAC valve controls the idle air control. i have replaced that, it was broken. but that didnt help. the injectors are brand new 280zxt browntops. i have a new cylinder head temperature sensor, the afm is also in good working condition and is unopened, the tps is working like it should.. the o2 sensor is new but it shows anything from .3 to .85 .. that is the range for it. is that too high? it keeps fluctuating around there. shouldnt it fluctuate from .4-.5 volts? Quote Link to comment Share on other sites More sharing options...
Guest GreenZ Posted January 24, 2003 Share Posted January 24, 2003 I am curious, what fuel pressure are you reading at idle on your car? I have the same rich running condition on my 83 ZXT, and my 81 ZXT liked to be rich also. It barely passed smog and I know I will have a hell of a time getting it by this year. With the vacuum hose on the regulator I get 30 psi. Disconnect the vacuum hose it goes up to 36 psi and the idle smooths out real nice with the hose plugged. I was thinking an adjustable fuel pressure regulator and some time on an exhaust gas analyzer could help to lean things out. If both the HC and CO levels were high I would think you had a leak at the intake manifold somewhere. Good luck, let us know what was wrong when you get this figured out. Quote Link to comment Share on other sites More sharing options...
Guest GreenZ Posted January 24, 2003 Share Posted January 24, 2003 One more thing, where did you get the injectors at? Are they new or rebuilt? I bought some injectors from Sherco Automotive, which are Napa brand injectors, and I don't think they are matched close to each other at all. One of them leaks the fuel pressure down and may be the cause of my rich condition. My email is SinCityZs@aol.com if you want to email me about your problem. Quote Link to comment Share on other sites More sharing options...
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