innerware Posted November 2, 2003 Share Posted November 2, 2003 Hey all, what would cause my stock 280z to not like to start up when it is cool? I think it is a fuel or air issue. It cranks just fine and when it finally takes it will loose rpms if I apply the gas. When I let it warm up for a couple of minutes it is fine. But if I don't let it warm up enough it will loose rpms and want to backfire. So I feel it can be a fuel or air issue. I have new plugs, airfilter, and just passed smog fine. My vacuum checked ok and this will only happen when it is below 65 degrees or so. I am in the Bay area of Northern Cali so it isn't too cold. Could my Air Flow meter be sticking when cool or my throttle body? I have all new ( year and a half old ) sensors. When I ran too rich it wasn't that bad but I just had the car adjusted to pass smog and now it is bad again. My injectors are all less than 2 years old too. It doesn't sound cold start valve issue since it chokes up on me right after start, plus it hasn't been that cold. Could it be a pressure regulator, or air regulator? I don't know where to look and how to test it if it is the problem. Any help is always appreciated as always. Thanks Quote Link to comment Share on other sites More sharing options...
Guest dpiatkin Posted November 29, 2003 Share Posted November 29, 2003 dont really hav any idea about your particular problem .....but I know where to get good step by step testing for these EFI components !! The HAYNES 280ZX manuals have fantastic step by step testing for almost every part in your EFI system !!! The Chiltons manual is a piece of sh#t !! and covers very very little that is helpful You will need a Ohmmeter with both low and high scale ranges and a voltmeter for DC...... with these your about set to go !! PS- check prices all over for these electronic parts as they are VERY expensive thru most places if even available. victoria british seems to have best prices that I've found for most items Quote Link to comment Share on other sites More sharing options...
Guest bushcutter6915 Posted January 18, 2004 Share Posted January 18, 2004 I was going over the archives and came across your post, I was looking in the same direction you were with the vacuum advance and plumping. Your car does or hopefullly did the exact same thing almost perbatum. Were you able to fix it or find out what was going on. I'm digging through every manual post, trying to problem solve. thanks will Quote Link to comment Share on other sites More sharing options...
datsunlover Posted January 18, 2004 Share Posted January 18, 2004 Ive got AFM checks in my album from a 1975 FSM. They might be of some help. Quote Link to comment Share on other sites More sharing options...
innerware Posted January 19, 2004 Author Share Posted January 19, 2004 Actually got the problem fixed. Hopefully it can help others. Kinda embarrassing though. Since I caused the problem a while back. After replacing my thermotime switch and temp sender and wires that attach to them about a year or so ago I plugged them into the wire harness backwards. So the engine was sending all kinds of wierd signals to the computer. I had the Z doctors find the problem. They say it is fairly common to see especially after an engine swap or head replacement. Didn't take them more than an hour to find. And can I say wow what a difference. It starts right up, everytime. I hope this helps a little. The sender and switch might be bad but are cheap and easy to replace if your wires aren't switched. Good luck, Kyle Quote Link to comment Share on other sites More sharing options...
Guest bushcutter6915 Posted January 20, 2004 Share Posted January 20, 2004 I switched the two yellow wires took me a few cranks and fired up, but It didn't die or studder it kept a consistent idle and when I pushed on the throttle it didn't die. The first time you fired it up after finding the problem did it start the first crank or did a take a couple. thanks for all your help If you have any problems I'll try and answer them will Quote Link to comment Share on other sites More sharing options...
innerware Posted January 20, 2004 Author Share Posted January 20, 2004 Well the shop did it. They said it fired right up and it was cold that day. Since then I have had no problems at all. It just fires right up and I can rev it good and strong. Hopefully this means that your problem is fixed. Good luck let me know if it is good to go. Quote Link to comment Share on other sites More sharing options...
Guest bushcutter6915 Posted January 21, 2004 Share Posted January 21, 2004 It started, but not after about 8 cranks or so once it caught and fired up it ran great idled and did not die so one part fixed still trying to get it to fire up on first crank. will Quote Link to comment Share on other sites More sharing options...
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