powershotnt Posted November 29, 2009 Share Posted November 29, 2009 1981 280zx 217K miles Car is hard to start. When warmed up under no load it revs good and smooth. Slight blue smoke. When in gear driving it coughs and hesitates till over 3000rpm. When cold after a few seconds of idling it coughs and back fires thru air cleaner when rev'd and smokes more than when warm. My test results when using starter only removing 1 plug at a time. #1. 141# #2. 143# #3. 143# #4 141# #5. 135# #6. 137# I have searched this forum and googled and looked thru shop manual. What is a good compression for the L28E (non turbo)? Any Ideas on cold start and under 3000rpm issues? I have changed fuel filter,cap and rotor. Quote Link to comment Share on other sites More sharing options...
powershotnt Posted November 29, 2009 Author Share Posted November 29, 2009 I did find minimum and standard compression in manual. 171 standard and 128 minimum so my engine is towards the lower end. My question still stands on engine running problems that I have. Quote Link to comment Share on other sites More sharing options...
Spooler Posted November 30, 2009 Share Posted November 30, 2009 It could be the Air regulator, 7th injector (cold start injector), head temp sensor, fuel pressure regulator, or you may have a vaccum leak somewhere. Had this happen before but it has been a while. Pull the plugs, are they gas soaked or fouled? Quote Link to comment Share on other sites More sharing options...
powershotnt Posted November 30, 2009 Author Share Posted November 30, 2009 I pulled the plugs when I did the compression check. I have to redo the compression check because I did it on a cold engine.My buddy told me it should be warm to get accurate readings? The plugs looked really good. I did have to change 3 different vacuum lines because they were bad. I will go thru and check all of them. Thanks for the list of sensors to check. Quote Link to comment Share on other sites More sharing options...
Pyro Posted November 30, 2009 Share Posted November 30, 2009 numbers look OK. compression gages can be wrong but the numbers look consistent which is the important thing. low compression numbers typically means a stretched timing chain which retards the cam timing. popping out the intake means a lean mixture and/or retarded ignition timing. a bad TTS can make it hard to start when cold. balancers slip which cause the timing mark to move, which will make adjustments to the ignition timing wrong (retarded). check for true tdc to see if the balance has moved. change the valve stem seals to stop the smoke. Quote Link to comment Share on other sites More sharing options...
spork Posted December 1, 2009 Share Posted December 1, 2009 If you can source a friend with a cylinder leak down tester, you may find that all your cylinders aren't near as equal as the compression test shows. A bad piston oil ring may mask a cylinder that has bigger problems. A leak down test will find the problem with the lower numbers (if warming the engine up prior to the compression test doesn't help). Quote Link to comment Share on other sites More sharing options...
powershotnt Posted December 1, 2009 Author Share Posted December 1, 2009 Thank you gentlemen. Took it to my buddys late sunday afternoon and he took his stethascope and told me #3 and #4 valves were ticking..so I am going to adjust the vavles this weekend..o.k...I know a ton of abreviations but I have searched this forum for TTS and cannot find it.. Throttle position sensor? I have the worst luck..One day I find the full list of abreviations and the next day could spend 2 hrs and not find it!(on this forum) I realize this thing has got 217k miles on it but it is going to be years and trips back and forth to the body shop and various other places so before I do the V8 swap and complete the restoration I need to drive it. I will ask around for a leak down tester. This weekend find true TDC and check my balancer. These are easy tries and cost me nothing..Too bad I have to tell my wife "sorry dear..honey do list is gonna have to wait." Thank you for the ideas. Quote Link to comment Share on other sites More sharing options...
Pyro Posted December 1, 2009 Share Posted December 1, 2009 thermal time switch. it is right next to the water temp sensor in the T-stat housing. the TTS and water temp sensor both have a 2 prong injector looking plug. clean both the plugs (tts and wts) and don't mix them up. Quote Link to comment Share on other sites More sharing options...
powershotnt Posted December 2, 2009 Author Share Posted December 2, 2009 I washed my engine down heavily with degreaser when I first got the car. The boots on all the connections are rotted. I got water into the TPS plug and it went into limp home mode. I will disconnect each sensor 1 by 1 and clean them..thank you. I really like the non $$$ tries at fixing it. Quote Link to comment Share on other sites More sharing options...
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