Natulv Posted September 10, 2010 Share Posted September 10, 2010 (edited) I bought a 1979 280zx a few weeks ago and cant figure out how to fix this problem. The engine seems to be "gasping" and backfiring a bit. I start the car and I have to rev it a little to get it to idle (even then idle seems reallly low). Also between 1000 and 2500 rpms it struggles, like it cant get fuel but theres abviously unburnt fuel due to the exhuast scent. I thought it would be an ignition issue so I replaced the plugs, wires, cap, rotor, and that doesnt seem to have done anything. odd thing is once it manages to hit 3000rpms it sounds and runs alot better. Any help appreciated Edited September 10, 2010 by Natulv Quote Link to comment Share on other sites More sharing options...
19762802+2 Posted September 10, 2010 Share Posted September 10, 2010 I bought a 1979 280zx a few weeks ago and cant figure out how to fix this problem. The engine seems to be "gasping" and backfiring a bit. I start the car and I have to rev it a little to get it to idle (even then idle seems reallly low). Also between 1000 and 2500 rpms it struggles, like it cant get fuel but theres abviously unburnt fuel due to the exhuast scent. I thought it would be an ignition issue so I replaced the plugs, wires, cap, rotor, and that doesnt seem to have done anything. Any help would be appreciated and thanks in advance Are you sure you put the wires back on in the right order? It sounds a lot like a problem my DD had when one of the wires came loose. Make sure you have all of the wires getting good connection on the distributor cap, sometimes the "connector" gets slid down inside the wire if that makes sense. Quote Link to comment Share on other sites More sharing options...
Natulv Posted September 10, 2010 Author Share Posted September 10, 2010 I checked the wires a few times, at first it ran really bad because I did reverse the 5 and 3 wires. I am completely baffled as to what could be the problem >.< Quote Link to comment Share on other sites More sharing options...
Natulv Posted September 10, 2010 Author Share Posted September 10, 2010 Update: I am going to go check the ignition coil at a suggestion from my friend, if that doesnt tell me whats up I will be back Quote Link to comment Share on other sites More sharing options...
19762802+2 Posted September 10, 2010 Share Posted September 10, 2010 I re-read your post and it seems like it may be a fuel injection problem, Try unplugging your Cold start injector it should be near the throttle body and see if that helps also do some research about the fuel injection it will help you out. Quote Link to comment Share on other sites More sharing options...
Natulv Posted September 10, 2010 Author Share Posted September 10, 2010 (edited) Well we got a new ignition coil and that seems to have helped alot. Took a meter to the old one and it was pretty shot. I will try the cold start idea definately. also I think the little exhaust problem may be an issue. The last owner of the car last decided for some reason or another to cut the exhaust off with a plasma cutter close to the wheel so it just heats the rubber. Do you think the back pressure not being there may be part of the problem? Edited September 10, 2010 by Natulv Quote Link to comment Share on other sites More sharing options...
ckolander Posted September 26, 2010 Share Posted September 26, 2010 You might also want to bypass the fuel damper, it's in between the fuel pump and the steel fuel line. That helped my Z a lot Quote Link to comment Share on other sites More sharing options...
gonzalezj1943 Posted September 26, 2010 Share Posted September 26, 2010 You might also want to bypass the fuel damper, it's in between the fuel pump and the steel fuel line. That helped my Z a lot by bypass the fuel damper do you mean take it off the car and just connect the hoses together? would it effect anything? Quote Link to comment Share on other sites More sharing options...
19762802+2 Posted September 26, 2010 Share Posted September 26, 2010 by bypass the fuel damper do you mean take it off the car and just connect the hoses together? would it effect anything? The fuel damper's original purpose was to smooth out the fluctations of pressure coming from the fuel pump for a smoother flow of gas. All you need to do is replace the hose and eliminate the fuel damper. Many people have run the car without it and its not a big issue not using it. Quote Link to comment Share on other sites More sharing options...
ckolander Posted September 26, 2010 Share Posted September 26, 2010 What he said Quote Link to comment Share on other sites More sharing options...
Natulv Posted October 1, 2010 Author Share Posted October 1, 2010 sorry bout lack of reply had a wicked few weeks at work . We put in some new injectors and mended the exhaust, which seems to have fixed the issue. Car fires up and sounds amazing, though it still backfires once in a while at 4500-6000 rpm. Disconnecting the cold start injector also helped. My new problem is the coolant on the passenger floorboard, apparently the heater core was bypassed poorly (a bolt in both hoses with a flimsy hose clamp). Quote Link to comment Share on other sites More sharing options...
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